Article

Post-Paleocene evolution of regional groundwater flow systems and their relation to petroleum accumulations, Taber area, Southern Alberta, Canada

Authors:
To read the full-text of this research, you can request a copy directly from the authors.

No full-text available

Request Full-text Paper PDF

To read the full-text of this research,
you can request a copy directly from the authors.

... In the interest of knowing, in which countries, the hydrogeochemical process of water is studied and analysed from the perspective of the theory of the Tóthian groundwater flow systems (TGFS), which is the approach proposed in this chapter. The TGFS also explains how the study of groundwater based on this theory assist in proposing a natural mitigation procedure for fluoride content in groundwater (Chebotarev 1955;Tóth , 1978Tóth , 1986Tóth , 1988Carrillo-Rivera et al. 2008). ...
... Based on the above, the groundwater recharge, throughflow, and discharge areas may be located at different elevations and different lithological relief. Discharge areas occur in the topographically lower sector; implying the presence of a groundwater flow system; that is, even if the lithology has a small hydraulic conductivity value suggesting that groundwater might not flow; however, discharge is always attesting; such movement is supported by its chemical evolution of the flowing water which according to Chebotarev (1955), , Tóth and Corbet (1986) the chemical composition of groundwater evolves from the recharging site to the discharge site. For this reason the water extracted in plains and valleys may have high content of Total Dissolved Solids and some trace elements. ...
... That is, considering from the recharge to the discharge zone, under the perspective of the groundwater flow systems in its geological context which reflects that the ions are incorporated and increasing their concentration in the flow system without reaching saturation, since during the longitudinal and vertical travel of the water the process of water-rock interaction results in the geochemical reactions that determine the sub-saturation in respect of that water mineral. However, they lead to increase in total dissolved solids concentration among these also some trace elements are included (Chevotarev 1955;Tóth , 1986Carrillo-Rivera et al. 1996;Ortega-Guerrero 2009;Huizar-Alvarez et al. 2016a;Cardona et al. , 2018. ...
Chapter
Full-text available
Análisis del funcionamiento Hidrológico de la Región de los Bajos Submeridionales de la Provincias de Santa Fe, Chaco y Santiago del Estero. Argentina.
... In the interest of knowing, in which countries, the hydrogeochemical process of water is studied and analysed from the perspective of the theory of the Tóthian groundwater flow systems (TGFS), which is the approach proposed in this chapter. The TGFS also explains how the study of groundwater based on this theory assist in proposing a natural mitigation procedure for fluoride content in groundwater (Chebotarev 1955;Tóth , 1978Tóth , 1986Tóth , 1988Carrillo-Rivera et al. 2008). ...
... Based on the above, the groundwater recharge, throughflow, and discharge areas may be located at different elevations and different lithological relief. Discharge areas occur in the topographically lower sector; implying the presence of a groundwater flow system; that is, even if the lithology has a small hydraulic conductivity value suggesting that groundwater might not flow; however, discharge is always attesting; such movement is supported by its chemical evolution of the flowing water which according to Chebotarev (1955), , Tóth and Corbet (1986) the chemical composition of groundwater evolves from the recharging site to the discharge site. For this reason the water extracted in plains and valleys may have high content of Total Dissolved Solids and some trace elements. ...
... That is, considering from the recharge to the discharge zone, under the perspective of the groundwater flow systems in its geological context which reflects that the ions are incorporated and increasing their concentration in the flow system without reaching saturation, since during the longitudinal and vertical travel of the water the process of water-rock interaction results in the geochemical reactions that determine the sub-saturation in respect of that water mineral. However, they lead to increase in total dissolved solids concentration among these also some trace elements are included (Chevotarev 1955;Tóth , 1986Carrillo-Rivera et al. 1996;Ortega-Guerrero 2009;Huizar-Alvarez et al. 2016a;Cardona et al. , 2018. ...
Chapter
The “Transboundary Aquifer” concept envisaged in the United Nations Resolution 63/124 “The Law of Transboundary Aquifers” has had a significant impact on the evaluation of transboundary aquifers around the world. In the Mexico–U.S.A. case, it has not been possible to officially determine the total number of shared aquifers, therefore, the evaluation of the systemic functioning of “Transboundary Groundwater” is to be settled; it represents an absent concept in the international transboundary water enactments. This work carries out an analysis based on scientific evidence and legal documents to determine the nature of the current conceptual discrepancies between the scientific definitions of “Transboundary Aquifer” and “Transboundary Groundwater.” Results support the need to incorporate a systemic vision of the functioning of groundwater, as well as the scientific homologation of concepts and methodologies applied by those states interested in jointly assessing groundwater as to avoid water conflicts in the context of its incipient integrated management.
... In the interest of knowing, in which countries, the hydrogeochemical process of water is studied and analysed from the perspective of the theory of the Tóthian groundwater flow systems (TGFS), which is the approach proposed in this chapter. The TGFS also explains how the study of groundwater based on this theory assist in proposing a natural mitigation procedure for fluoride content in groundwater (Chebotarev 1955;Tóth , 1978Tóth , 1986Tóth , 1988Carrillo-Rivera et al. 2008). ...
... Based on the above, the groundwater recharge, throughflow, and discharge areas may be located at different elevations and different lithological relief. Discharge areas occur in the topographically lower sector; implying the presence of a groundwater flow system; that is, even if the lithology has a small hydraulic conductivity value suggesting that groundwater might not flow; however, discharge is always attesting; such movement is supported by its chemical evolution of the flowing water which according to Chebotarev (1955), , Tóth and Corbet (1986) the chemical composition of groundwater evolves from the recharging site to the discharge site. For this reason the water extracted in plains and valleys may have high content of Total Dissolved Solids and some trace elements. ...
... That is, considering from the recharge to the discharge zone, under the perspective of the groundwater flow systems in its geological context which reflects that the ions are incorporated and increasing their concentration in the flow system without reaching saturation, since during the longitudinal and vertical travel of the water the process of water-rock interaction results in the geochemical reactions that determine the sub-saturation in respect of that water mineral. However, they lead to increase in total dissolved solids concentration among these also some trace elements are included (Chevotarev 1955;Tóth , 1986Carrillo-Rivera et al. 1996;Ortega-Guerrero 2009;Huizar-Alvarez et al. 2016a;Cardona et al. , 2018. ...
Chapter
The water debate seems to be summarized in two fully opposite positions: (i) the Dublin Conference of 1992 perspective favors movements that defend against the introduction of market economies in the management of water, arguing the production of “water scarcity”; and (ii) the groups calling for water as a “common good,” recognizing that there is enough fresh water access but an unequal appropriation. However, both lack to propose the required scientific research to guarantee a hidden basic concept: water insecurity. Countries such as China, Japan, Australia, and Canada, have implemented methodologies as the Tóthian groundwater flow system (Tóth 1962, 1999, 2016), concept that provides with solid interdisciplinary analyses of the related ambient components. In Mexico the situation is different, various political-administrative factors have prevailed over the scientific understanding of the functioning of groundwater. Through three case studies: Querétaro State, and the Northern, and Southern international boundaries of Mexico (transboundary groundwater) that reflect challenges in water management; such as the characterization and evaluation of groundwater flow systems shared. This chapter seeks to contribute to reveal the political and scientific elements that characterize groundwater management in Mexico, and its relation to Water Security.
... Groundwater flow directions in the MRA, recharge and discharge areas can be inferred from the potentiometric surface of the aquifer. Parts of the potentiometric surface of the MRA were mapped by Meyboom (1960); Borneuf (1974); Toth and Corbet (1986) and AGRA Earth and Environmental (1998) in southern Alberta and by Zimmerman (1967); Levings (1982a), and Tuck (1993) in northern Montana. ...
... High piezometric heads were also measured in the area east of Manyberries and in the southeast corner of the study area, indicating a component of groundwater flow laterally from other geological units. This water originates in the Cypress Hills (Toth and Corbet 1986) and the Bears Paw Mountains (Levings 1 9 8 2 a ) . P i e z o m e t r i c l o w s a r e l o c a t e d i n t h e Pakowki Lake area and in the northern part of the study area in Alberta and along Cut Bank Creek and Big Sandy Creek in Montana. ...
... As depicted in the schematic diagram of Fig. 8c, the high topographic area of the Cypress Hills is also presumed to be a regional recharge area for surficial sediments whose large hydraulic heads induce downward flow through the aquitard overlying the MRA, thus explaining the high potentiometric heads observed east of Manyberries (Fig. 7). This cross-formational flow process was also inferred by Toth and Corbet (1986). ...
Article
Full-text available
A conceptual model of the transboundary Milk River Aquifer (MRA), extending across the Canada–USA border, was developed based on literature, focused fieldwork and a three-dimensional geological model. The MRA corresponds to the Virgelle Member of the Milk River Formation (Eagle Formation in Montana, USA) and it is an important groundwater resource over a large area (25,000 km2). The Virgelle outcrops near the international border and along the Sweet Grass Arch in Montana. The down-gradient limit of the MRA is the unconformity separating the Virgelle from the gas-bearing sandy shale of the Alderson Member. The MRA is confined above by the Pakowki/Claggett Formations aquitards and below by the Colorado Group aquitard. The MRA contains higher transmissivity areas resulting in preferential flowpaths, confirmed by natural geochemical tracers. Tritium and 14C delineate restricted recharge areas along the outcrops on both sides of the international border. Drastic decreases in horizontal hydraulic gradients indicate that the Milk River intercepts a large proportion of groundwater flowing to the north from the recharge area. Downgradient of the Milk River, groundwater movement is slow, as shown by 36Cl residence times exceeding 1 Ma. These slow velocities imply that groundwater discharge downgradient of the Milk River is via vertical leakage through the Colorado Group and upward along buried valleys, which act as drains and correspond to artesian areas. When confined, the MRA contains a fossil groundwater resource, not significantly renewed by modern recharge. Groundwater exploitation thus far exceeds recharge, a situation requiring properly managed MRA groundwater depletion.
... These data suggest that the coproduced water in this study is a mixture of paleometeoric water and connate water. Several mixing events may have occurred including meteoric flushing as a result of regression near the end of the Campanian, regional fluid recharge from Late Cretaceous to Eocene orogenic events (Laramide) west of the study area, or recharge associated with local uplift since the late Miocene (Toth and Corbet, 1986). The ages of four water samples in this study based on 129 I/I ratios (35.6, 51.0, 53.6 and 65.6 Ma) and the δ 18 O and δD water data are consistent with Cretaceous to Paleogene mixing or migration events. ...
... Rice et al. (1990) proposed that gas in the Bowdoin dome exsolved from formation water from uplift and erosion during Late Cretaceous and (or) early Tertiary time. Toth and Corbet (1986) proposed that gas in southeast Alberta came out of solution in response to about 700 meters of erosional unloading beginning about 5 Ma. Thus the critical moment of the Colorado and Montana gas systems may be a combination of geologic events including the lowering of sea level in the Late Cretaceous, and subsequent uplift and erosion events (Fig. 11). ...
Article
Full-text available
Cenomanian to Campanian rocks of north-central Montana contain shallow economic accumulations of dry natural gas derived from microbial methanogenesis. The methanogens utilized carbon dioxide derived from organic matter in the marginal marine sediments and hydrogen from in situ pore water to generate methane. The most recent USGS assessment of the shallow gas resources of eastern Montana used a petroleum systems approach, identifying the critical components of a petroleum system (source rock, reservoir rock, seal rock, and trap) and their temporal relationships. As a part of this effort, geo-chemical data from natural gas wells and associated formation waters were used to identify two microbial gas systems and the timing of methanogenesis. Two microbial gas families are identified in north-central Montana based on stable carbon isotope and gas composition. The Montana Group gas family has heavier δ 13 C methane values, slightly lighter δD methane values, and a lower carbon dioxide and nitrogen content than the Colorado Group gas family. The two gas families may reflect, in part, the source rock depositional environments, with the Colorado Group rocks representing a more offshore marine depositional environment and the Montana Group rocks representing proximal marine, deltaic and nonmarine depositional environments. Assuming the gas families reflect only source rock characteristics, two microbial petroleum systems can be defined. The first petroleum system, called the Colorado Group microbial gas system, consists of Colorado Group rocks with the shales in the Belle Fourche Formation, Greenhorn Formation, and the Carlile Shale as the pre-sumed source rocks and the interbedded Phillips and Bowdoin sandstones and the Greenhorn Formation limestones as reservoirs. The second petroleum system, called the Montana Group microbial gas system, consists of the Montana Group rocks that include the Gammon Shale and possibly the Claggett Shale as source rocks and the Eagle Sandstone and the Judith River Formation as reservoirs. The Niobrara Formation is tentatively placed in the former system. The geographic extent of the two microbial systems is much larger than the study area and includes an area at least from the Alberta basin to the northwest to the Powder River basin to the southeast. Upper Cretaceous microbial gas accumulations have been recog-nized along these basin margins at burial depths less than 3000 ft, but have not been recognized within the deeper parts of the basins because subsequent charge of thermogenic oil and gas masks the preexisting microbial gas accumulations. Methanogenesis began soon after the deposition (early-stage methanogenesis) of the Cenomanian to Campanian source sediments, and was either sustained or rejuvenated by episodic meteoric water influx until sometime in the Paleogene. Methanogenesis probably continued until CO 2 and hydrogen were depleted or the pore size was compacted to below tolerance levels of the methanogens. The composition of the Montana and Colorado Group gases and coproduced formation water precludes a scenario of late-stage methanogenesis like the Antrim gas system in the Michigan basin. Some portion of the methane charge was originally dissolved in the pore waters, and subsequent reduction in hydrostatic pressure caused the methane to exsolve and migrate into local stratigraphic and structural traps.
... Produced water represents the largest by-product 34 of oil and gas production, and in 2017 the total volume of produced water in the US exceeded 3.8 35 billion m 3 (Veil 2020). Volumes of produced water have increased over the past two decades 36 (Lutz et have used the cumulative interference index developed by Toth and Corbet (1986) to account for 68 the radial proximity of a drillstem test to a production or injection well and remove tests affected 69 by production or injection wells. Other approaches to removing pressure measurements affected 70 by production and injection, including visual inspection (Bair et al. 1985;LeFever 1998) net gain in water (Ferguson 2015). ...
Article
Full-text available
Large volumes of saline formation water are both produced from and injected into sedimentary basins as a by‐product of oil and gas production. Despite this, the location of production and injection wells has not been studied in detail at the regional scale and the effects on deep groundwater flow patterns (i.e. below the base of groundwater protection) possibly driving fluid flow towards shallow aquifers remain uncertain. Even where injection and production volumes are equal at the basin scale, local changes in hydraulic head can occur due to the distribution of production and injection wells. In the Canadian portion of the Williston Basin, over 4.6 x 109 m3 of water has been co‐produced with 5.4 x 108 m3 of oil, and over 5.5 x 109 m3 of water has been injected into the subsurface for saltwater disposal or enhanced oil recovery (EOR). Despite approximately equal values of produced and injected fluids at the sedimentary basin scale over the history of development, cumulative fluid deficits and surpluses per unit area in excess of a few 100 mm are present at scales of a few 100 km2. Fluid fluxes associated with oil and gas activities since 1950 likely exceed background groundwater fluxes in these areas. Modelled pressures capable of creating upward hydraulic gradients are predicted for the Midale Member and Mannville Group, two of the strata with the highest amounts of injection in the study area. This could lead to upward leakage of fluids if permeable pathways, such as leaky wells, are present.
... A similar low along the Coronach Trough separates the Wood Mountain and Roncott highs. It is not as pervasive throughout the Paleozoic section or as pronounced as that in the Hummingbird Trough, and is probably due to a fractured permeable lens that has acted as a preferred zone of conver Toth and Corbet (1986) and by Parks (1989). ...
Article
Formation water flow patterns and chemistry have been a controlling influence on the migration, accumulation and preservation of hydrocarbons of the Williston Basin in south-central Saskatche­ wan. Two major competing flow regimes are active in the Paleozoic aquifers of the region. A dominant, gravity driven, meteoric flow system with a potentiometric surface that resembles the topographic surface, is entering the region from the southwest. A second flow system of deep basin brines from the center of the Williston Basin enters the region from the southeast. It is part of a sluggish basin-wide flow system, apparently unrelated to local topography. The brines are important agents of transport and preservation of petroleum in the region. The distribution of the region's hydrocarbon accumulations may be explained in terms of the hydraulic theory of petroleum migration. Oil was transported from mature source beds with the formation waters toward traps in potentiometric lows. Cross-formational migration of hydrocarbons has occurred upwards through a linear zone of salt removal known as the Hummingbird trough. Future oil discoveries in Paleozoic aquifers of south-central Saskatchewan will likely be made in potentiometric lows east of the Hummingbird Trough and along the Coronach Trough.
... According to the hierarchy of GFS, basin scale groundwater systems can be divided into local (LFS), intermediate (IFS), and regional (RFS) flow systems (Han et al. 2009). Many researchers (Stuyfzand 1999;Winter 1999;Tóth and Corbet 1986) have used the groundwater flow system theory to solving problems in hydrogeology. In order to effectively develop and manage groundwater resources, a better understanding is required of the hydrochemical and isotopic characteristics of groundwater, as well as the origin and the age (Su et al. 2009). ...
Article
Full-text available
The Yinchuan plain is located in the arid climate zone of NW China. The western margin of the plain is the Helan mountain connecting a series of normal slip faults. The eastern margin of the plain connects with the Yellow River and adjacents with the Ordos platform. The south of the plain is bordered by the EN fault of the Niushou mountain. The bottom of the plain is the Carboniferous, Permian, or Ordovician rocks. Based on the analysis of groundwater hydrochemical and isotopic indicators, this study aims to identify the groundwater recharge and discharge in the Yinchuan plain, China. The hydrochemical types of the groundwater are HCO3–SO4 in the west, HCO3–Cl in the middle, and Cl–SO4 in the east. The hydrochemical types are HCO3–SO4 in the south, HCO3–Cl and SO4–HCO3 in the middle. The hydrochemical types are complex in the north, mainly SO4–HCO3 and Cl–SO4. Deuterium, 18O, and tritium values of groundwater indicate that groundwater recharge sources include precipitation, bedrock fissure water, and irrigation return water. Groundwater discharges include evaporation, abstraction, and discharge to surface water. According to the EW isotopic profile, the groundwater flow system (GFS) in the Yinchuan plain can be divided into local flow systems (LFS) and regional flow systems (RFS). Groundwater has lower TDS and higher tritium in the southern Yellow River alluvial plain and groundwater age ranges from 6 to 25 years. The range of groundwater renewal rates is from 11 to 15 % a−1. The depth of the water cycle is small, and groundwater circulates fast and has high renewal rates. Groundwater has higher TDS and lower tritium in the northern Yellow River alluvial plain. The range of groundwater age is from 45 to 57 years, and renewal rate is from 6 to 0.1 % a−1. The depth of the water cycle is larger. Groundwater circulates slowly and has low renewal rates.
... Besides the need for information that most often is not available, the ''Theis method'' can be applied only manually, thus becoming absolutely impractical for large databases. Based on the logarithmic ''Theis solution'' to the drawdown problem, and by analogy to water testing, Tóth and Corbet (1987) assumed that, all other factors being equal, the effect of production is directly proportional to an interference index I defined as: ...
Article
Analysis of hydraulic heads and chemical compositions of Devonian formation waters in the west central part of the Alberta Basin, Canada, characterizes the origin of formation waters and migration of brines. The Devonian succession in the study area lies 2000–5000 m below the ground surface, and has an approximate total thickness of 1000 m and an average slope of 15 m/km. Four Devonian aquifers are present in the study area, which form two aquifer systems [i.e., a Middle–Upper Devonian aquifer system (MUDAS) consisting of the Elk Point and Woodbend–Beaverhill Lake aquifers, and an Upper Devonian aquifer system (UDAS) consisting of the Winterburn and Wabamun aquifers]. The Ireton is an effective aquitard between these two systems in the eastern parts of the study area. The entire Devonian succession is confined below by efficient aquitards of the underlying Cambrian shales and/or the Precambrian basement, and above by overlying Carboniferous shales of the Exshaw and Lower Banff Formations.The formation water chemistry shows that the Devonian succession contains two distinct brine types: a ‘heavy brine,’ located updip, defined approximately by TDS >200 g/l, and a ‘light brine’ with TDS
... The Theis formula takes the form of a logarithmic dependence on t=r 2 : Besides the need for information that most often is not available, the Theis method can be applied only manually, thus becoming absolutely impractical for large databases. Based on the logarithmic Theis solution to the drawdown problem, and by analogy to water-testing, Toth and Corbet (1986) assumed that, all other factors being equal, the effect of production is directly proportional to an interference index, I, de®ned as I logt=r 2 Table 2 Culling criteria for formation water analyses used in the automatic culling procedure (from Hitchon and Brulotte (1994) For ease of use, t is measured in years and r in miles or kilometers. Tests with a high interference index from the nearest producing well were identi®ed, individually examined and in most cases eliminated from the data set. ...
Article
The flow and chemistry of formation waters was analyzed in the Mississippian–Jurassic succession in the west-central part of the Alberta Basin, using publicly available standard chemical analyses of formation waters and drillstem test data collected by the petroleum industry in Alberta. The interpretation of the thoroughly culled hydrogeological data show that a transition between a southern and a northern basin-scale flow system takes place in the study area. In the southeastern half of the study area, the Mississippian–Jurassic hydrostratigraphic group represents a single continuous carbonate–sandstone aquifer system, consisting of the Lower Jurassic Nordegg Member, the Triassic Montney Formation, the Permian Belloy Formation and the Mississippian Stoddart and Rundle groups. The confining units are the competent Fernie and Exshaw–Banff aquitards at the top and base, respectively. The salinity of formation waters increases northwestwards from ∼50 to ∼150 g/l, while the bicarbonate content decreases in similar fashion from >3 to ∼0.5 g/l. The flow pattern, based on hydraulic heads, and chemical composition of formation waters indicate decreasing mixing of meteoric water, carried northward in the southern basin-scale long-range system, with heavier connate water present in the northern part of the study area. In the center and in the northeast, the Permian and Mississippian carbonates, and the Triassic Montney and Charlie Lake–Halfway sandstones form individual aquifers separated by the intervening Doig–Montney aquitard. The flow in the Charlie Lake–Halfway and the Permo-Mississippian aquifers is directed east–northeastward from the deformation front into the overlying aquitards, or discharging into the southern basin-scale flow system, respectively. Only in the Montney aquifer, the flow is directed inward, south–southwestward, drawn into a local hydrocarbon-saturated sink, which is created by a higher rate of gas escape than of gas generation through a low-permeability and capillary-seal region. The high salinity, in the 130–150 g/l range, and low bicarbonate content (∼0.5 g/l) of formation waters in the northern part of the study area indicate a connate origin. The relation of Na–Ca–Cl–Br concentrations in the formation waters suggest that these waters initially originated as seawater that was altered to some degree by subaerial evaporation and dolomitization, but halite dissolution probably is the main source of salinity. The driving mechanism for the flow of these waters could be either tectonic expulsion from deep strata in the deformed part of the basin, as suggested by the high salinity of these waters, or topography-driven meteoric recharge in the Rocky Mountains through a tortuous path, unidentified as yet. The integrated interpretation of flow and chemistry of formation water shows that Mississippian–Jurassic formation waters in the deep, west-central parts of the Alberta Basin have been influenced less by mixing with meteoric water than was identified previously in the central, southern and northern parts of the basin. The main reasons for the isolation of ‘relict’ Mississippian–Jurassic formation waters in the deep Alberta Basin are effective confining aquitards and the fact that this area is influenced only marginally by mixing with meteoric water carried by a gravity-driven flow system.
... These studies have revealed or confirmed (1) the hydraulically continuous nature of the rock framework, which facilitates large-scale crossformational flow systems; (2) time lags in the adjustments of flow patterns to changing boundary conditions, ranging on the time spectrum from the human to the geological scales; and (3) the multiplicity of possible flow-inducing energy sources. It has also become obvious that, although in many respects different from their small-basin counterparts, a wide variety of geologic phenomena is associated with the large-scale flow systems (Bethke 1985;Bredehoeft and Hanshaw 1968;Erdélyi 1976;Goff and Williams 1987;Neuman and Witherspoon 1971;Neuzil and Pollock 1983;Neuzil et al. 1984;Parnell 1994;Tóth 1978;Tóth and Corbet 1986;Tóth and Millar 1983). ...
Article
Full-text available
The objective of the present paper is to show that groundwater is a general geologic agent. This perception could not, and did not, evolve until the system nature of basinal groundwater flow and its properties, geometries, and controlling factors became recognized and understood through the 1960s and 1970s. The two fundamental causes for groundwater's active role in nature are its ability to interact with the ambient environment and the systematized spatial distribution of its flow. Interaction and flow occur simultaneously at all scales of space and time, although at correspondingly varying rates and intensities. Thus, effects of groundwater flow are created from the land surface to the greatest depths of the porous parts of the Earth's crust, and from a day's length through geologic times. Three main types of interaction between groundwater and environment are identified in this paper, with several special processes for each one, namely: (1) Chemical interaction, with processes of dissolution, hydration, hydrolysis, oxidation-reduction, attack by acids, chemical precipitation, base exchange, sulfate reduction, concentration, and ultrafiltration or osmosis; (2) Physical interaction, with processes of lubrication and pore-pressure modification; and (3) Kinetic interaction, with the transport processes of water, aqueous and nonaqueous matter, and heat. Owing to the transporting ability and spatial patterns of basinal flow, the effects of interaction are cumulative and distributed according to the geometries of the flow systems. The number and diversity of natural phenomena that are generated by groundwater flow are almost unlimited, due to the fact that the relatively few basic types are modified by some or all of the three components of the hydrogeologic environment: topography, geology, and climate. The six basic groups into which manifestations of groundwater flow have been divided are: (1) Hydrology and hydraulics; (2) Chemistry and mineralogy; (3) Vegetation; (4) Soil and rock mechanics; (5) Geomorphology; and (6) Transport and accumulation. Based on such a diversity of effects and manifestations, it is concluded that groundwater is a general geologic agent.
Chapter
Personal health and that of animals are often associated with the chemical composition of the groundwater they ingest. This primary source of water supply may affect the health status when significant changes in the concentration of some trace elements dissolved in drinking water are present. Indeed, adverse health effects occur due to chronic exposure to a high level of trace elements in drinking water. For example, groundwater consumption rich in arsenic or fluoride is causing severe and harmful health effects in broad sectors of the population in several countries. In Mexico, the quality of the drinking water supply is at risk due to water of an undesirable composition that rises to the extraction level of wells. This water inflow is with natural mineralization rich in certain trace elements that have been increasing with extraction time as well as with the obtained quantity; in other cases, there is a pollution effect by local inhabitants. The interest of this chapter is twofold: firstly, is to present different regions of Mexico with environmental and health responses related to groundwater consumption. The second is to emphasize the need to study the chemical evolution of groundwater based on the dynamic concept of the Tóthian groundwater flow systems.
Article
Based on analysis of groundwater hydrochemical and isotopic indicators, this article aims to identify the groundwater flow systems in the Yangwu River alluvial fan, in the Xinzhou Basin, China. Groundwater δ2H and δ18O values indicate that the origin of groundwater is mainly from precipitation, with local evaporative influence. d-excess values lower than 10% in most groundwaters suggest a cold climate during recharge in the area. Major ion chemistry, including rCa/rMg and rNa/rCl ratios, show that groundwater salinization is probably dominated by water–rock interaction (e.g., silicate mineral weathering, dissolution of calcite and dolomite and cation exchange) in the Yangwu River alluvial fan, and locally by intensive evapotranspiration in the Hutuo River valley. Cl and Sr concentrations follow an increasing trend in shallow groundwater affected by evaporation, and a decreasing trend in deep groundwater. 87Sr/86Sr ratios reflect the variety of lithologies encountered during throughflow. The groundwater flow systems (GFS) of the Yangwu River alluvial fan include local and intermediate flow systems. Hydrogeochemical modeling results, simulated using PHREEQC, reveal water–rock interaction processes along different flow paths. This modeling method is more effective for characterizing flow paths in the intermediate system than in the local system. Artificial exploitation on groundwater in the alluvial fan enhances mixing between different groundwater flow systems.
Thesis
Full-text available
Dès le début du 20ème siècle, les eaux souterraines de l’aquifère transfrontalier Milk River (MRA) ont constitué une importante ressource dans le sud de l’Alberta (Canada) et le nord du Montana (USA). L’utilisation intensive de cette ressource sous un climat semi-aride a provoqué une baisse importante des niveaux d’eau localement, si bien que des inquiétudes concernant la pérennité du MRA sont apparues dès les années 60. Les études précédentes du MRA étaient limitées par les frontières nationales, empêchant ainsi une compréhension complète de la dynamique de l’aquifère. L’objectif de cette thèse était de réaliser une étude transfrontalière du MRA afin de caractériser cette ressource régionale d’eau souterraine selon ses limites naturelles. À cette fin, trois modèles transfrontaliers ont été réalisés: un modèle géologique, un modèle conceptuel hydrogéologique et un modèle numérique d’écoulement souterrain. Des travaux de terrain de part et d’autre de la frontière Canada/USA et une revue de littérature exhaustive des études précédentes ont supporté la réalisation de ces modèles. De plus, une première évaluation des niveaux d’exploitation historiques du MRA a été réalisée en Alberta.Le modèle géologique 3D (50 000 km2) représente le MRA (Membre Virgelle de la Formation Milk River/Eagle) et ses unités confinantes continûment à travers la frontière internationale. Le développement de ce modèle a requis une harmonisation des nombreuses nomenclatures stratigraphiques de la région et la délimitation transfrontalière du MRA.Le modèle conceptuel hydrogéologique du MRA a montré deux flux d’écoulement souterrains transfrontaliers, dirigés du Montana vers l’Alberta. La Milk River intercepte la majeure partie du flux souterrain venant du sud, si bien que l’écoulement au nord de la rivière est très faible. Les analyses isotopiques confirment que les eaux du MRA sont principalement fossiles à l’exception de la zone de recharge située le long de la zone d’affleurement du MRA. Les zones du MRA avec une forte conductivité hydraulique et de faibles concentrations en chlorures correspondent à des voies d’écoulement préférentielles. L’émergence des eaux du MRA a lieu via la drainance à travers les unités confinantes notamment le long des vallées enfouies.Le modèle numérique (26 000 km2) d’écoulement souterrain du MRA en régime permanent est une transposition des modèles géologique et conceptuel. Il montre que le modèle conceptuel précédemment développé est hydrauliquement plausible. Le modèle d’écoulement donne une meilleure compréhension du système aquifère en représentant la dynamique de l’écoulement souterrain dans la situation pré-exploitation. Le traçage de particules indique des temps de résidence advectifs de près de 750 000 ans à la limite nord du MRA, ce qui est inférieur aux âges obtenus par les analyses isotopiques (2 Ma).Les bilans en eau des modèles conceptuels et numériques montrent tous les deux que l'extraction de l'eau souterraine dépasse de loin la recharge au nord de la Milk River.Un modèle d'écoulement transitoire serait requis pour définir le volume d'eau provenant de l'emmagasinement dans le MRA et préciser le rôle des aquitards durant le pompage. Par ailleurs, en tant que ressource internationale partagée, une gestion transfrontalière des eaux du MRA serait justifiée dans la région comprise entre la zone de recharge au Montana et le sud de la Milk River en Alberta. Ainsi, ces trois modèles transfrontaliers du MRA forment une base commune internationale de connaissances scientifiques à l'échelle de l'aquifère et pourraient supporter l'évaluation future du meilleur usage possible de cette ressource partagée et limitée. De futurs travaux peuvent inclure l'effet des champs de gaz localisés aux limites du MRA et les conditions paléo-hydrogéologiques liées à l'évolution géochimiqie de l'au souterraine.
Article
The stratum pressure characteristics of Mesozoic reservoirs in the Ordos Basin were first studied. It was found that the Mesozoic reservoirs were mainly ultra-underpressured reservoirs with an average stratum pressure coefficient of 0.63–0.86 and the differences in the abnormal underpressure between the different regions and layers were distinct. The results showed that with increases in the eroded stratum thickness and temperature decrease in the reservoirs, the stratum pressure coefficients showed a decreasing trend. The pore water volume contraction in the Yanchang Formation was from 0.82% to 1.94% after tectonic uplift and stratum temperature reduction. It was proposed that because of the strong uplift of the basin for a long time at the end of the Cretaceous, the function of stratum erosion and paleotemperature reduction resulted in the formation of underpressured reservoirs. It is considered that this underpressured closed system of the Mesozoic in the Ordos Basin was advantageous for reservoir preservation and might have played an important role in adjustment, re-enrichment of hydrocarbons by migration, and oil and water distribution in reservoirs. The formation of underpressured anhydrous sand lens reservoirs in the Chang 7 subsection could be related to the distribution of such an underpressured closed system.
Article
Groundwater capture and storage loss play a major role in the sustainable exploitation of a regional aquifer. This study aimed to identify the impact of major and long-term groundwater exploitation on a regional aquifer system to understand the processes controlling the sustainable exploitation of the transboundary Milk River Aquifer (MRA). The MRA extends over 26,300 km², being a major water resource across southern Alberta (Canada) and northern Montana (USA). Concerns about the sustainability of the MRA were raised as the century-old exploitation has led to important drawdowns and the local loss of historical artesian conditions. A steady-state numerical model of the regional flow system was developed and calibrated against hydraulic heads, groundwater fluxes, and the area with flowing artesian wells. Four groundwater abstraction scenarios were simulated: 1) natural flow conditions without exploitation; 2) the mean abstraction rate over the last 108 years; 3) the historical maximum global abstraction rate of the MRA; and 4) a theoretical high abstraction rate based on the maximum rate estimated for each MRA exploitation zone. The numerical model agrees with the previously formulated conceptual model and supports its hydraulic plausibility. Results show that MRA exploitation has led to a major change in flow patterns to sustain groundwater abstraction. The MRA water balance under exploitation indicates that more recharge and reduced seepage to bedrock valleys compensate groundwater withdrawals. Based on its impact on regional discharge and the reduction in MRA storage, the mean historical level of exploitation of the MRA appears sustainable. Larger exploitation rates would significantly reduce groundwater discharge to surface seepage locations and lead to a larger reduction in groundwater storage in the MRA. Modeling also illustrates that the MRA is an internationally shared resource. This situation would justify a joint management of the aquifer system between Canada and USA; especially in the area comprised between the recharge area in Montana and the Canadian reach of the Milk River.
Article
Sandstone reservoirs of the Mannville Group in southern Alberta host petroleum and natural gas deposits with abnormally high amounts of CO2 and H2S. Produced water and gas chemistry and isotopic composition suggests that bacterial sulphate reduction has taken place. Limited isotopic data for gas samples indicate that CO2 is organic, with calcite dissolution accounting for intermediate δ13C values for bicarbonate. CO2 and H2S are thought to be formed by bacterial sulphate reduction (BSR), the rate of which is dependent on the rate of supply of sulphate. H2S has been precipitated as pyrite and removed from the system. CO2, from both bacterial sulphate reduction and resulting water–rock reactions, has accumulated in quartz-rich sandstone reservoir rocks causing the amount of CO2 in the gas to be much higher than H2S. Anomalously high CO2 and H2S concentrations are coincident with the Jurassic subcrop edge and are related to cross formational fluid flow. Sulphate-rich waters from Mississippian aquifer units that underlie the Jurassic aquitard mix with waters in Mannville sandstone at the subcrop edge. Organic acids ratios in Mannville waters suggest that coaly material, not petroleum hydrocarbons, may provide the organic food source required for sulphate reducing bacteria.
Article
The Sudanese rift structures form intracontinental basins, bordered on all sides by anorogenic terrain. These basins are seen as the result of a multistructural system of rifts which appear to have been activated several times since the Palaeozoic. Improved methods of dating and extensive geophysical surveys have led to a better understanding of the mobile belts and the Basement rocks in the general environs of the basins, and of the elevated blocks and highs surrounding the sedimentary basins. Detailed mapping and extensive drilling in the sedimentary basins led to a better understanding of the Phanerozoic. The rapid rate of uplift and subsidence have assisted in the rapid accumulation and filling of the basins with unconsolidated sediments, ranging from a few hundred metres to some thousand metres. The rift structures contain sediments of several age groups, origin and mode of deposition. Some of them are as old as the Palaeozoic passing through to Mesozoic, Tertiary and Quaternary (Bahr El Arab rift and Blue Nile rift). The thickness of the Tertiary sediments exceeds 15 km in Bahr El Arab rift.
Article
The Milk River artesian aquifer underlies 15 000 km2 of southern Alberta, Canada. It consists of thin (30-75 m thick) sandstone and is confined above by the Pakowki shale (typically 120 m thick) and below by the Colorado shale. The aquifer subcrops in southern Alberta and northern Montana. Groundwater movement is to the north, west and east from the outcrop area (dominant recharge area). Cl- and I- concentrations increase in the direction of flow from less than 0.05 and 0.001 mmol/L, respectively, near the recharge area to more than 140 and 0.15 mmol/L at the northern edge of the aquifer. Similarly, waters become more enriched in oxygen 18 and deuterium from less than -21.0 and -167‰ near the recharge area to values approaching -8.0 and -70.0‰ in the north. Isotope values in the recharge area plot on the global meteoric water line indicate that the the recharge waters are isotopically unaltered meteoric waters. Downgradient from the recharge area the data deviate from the meteoric water line (slope of 6.3 instead of 8.0). Three mechanisms have been advanced to explain the origin of the chemical and isotopic patterns: the introduction of connate formation water through the Colorado shale and subsequent mixing with infiltrating meteoric water; a finite source of meteoric recharge mixing with more saline water in the aquifer; and chemical and isotopic enrichment due to ion filtration. -from Authors
Article
Full-text available
Naturally transient flow (NTF) occurs when a groundwater regime fails to accommodate geologic changes. This paper describes a conspicuous NTF signature entirely within a low-permeability shale in an eroded basin. Flow in the shale appears to be a lagging hydrodynamic response to mechanical rebound and cooling from erosion; careful, long-term pressure measurements revealed a consistent pattern of low hydraulic head with the minimum within the shale. Available data are sufficient to rule out alternate causes of the pressure regime, and to construct a meaningful quantitative model of the effects of erosion. The shale behaves as a Kelvin substance in tests, but theoretical considerations suggest that its deformation during erosion mimics elastic behavior, permitting the model to be based on poroelasticity. Pressure patterns similar to that observed can be produced by incorporating into the model independent estimates of the shale's hydraulic, mechanical, and thermal properties and a reconstruction of the area's erosion history. The results confirm that local permeability is between 10-21 and 10-20 m2 (hydraulic conductivity between 10-14 and 10-13 m/s), in contrast to the higher regional permeability of 2×10-16 m2 (hydraulic conductivity of 2× 0-9 m/s) determined in an earlier study. Exploration techniques employed in this study could reveal similar NTF regimes in the future.
Article
Fluid pressures too low to be in equilibrium with the topography of the land surface occur in Cretaceous sediments over much of the western Canada sedimentary basin. We used a numerical model to study the origin of low pressure in southern Alberta and its effects on patterns of regional groundwater flow over the past 5 million years. The model accounts for changes in basin topography, conduction and advection of heat, cooling of pore fluid, and rebound of pore volume during erosion. Results show that the ˜3 MPa of underpressuring observed in this region could have formed because the pore volume of sediments expanded slightly as Pliocene-Pleistocene erosion removed some of the confining load. Our calculations provide an estimate for the upper limit for the permeability of Cretaceous shales on a regional scale because results match observed pressures only if we assign vertical permeabilities less than 3 × 10-20 m2 to these sediments. Pore fluid cooled and contracted as erosion reduced the burial depth of the sediments, but this effect could not have played a significant role in generating low pressure unless Cretaceous shales in southern Alberta are extremely stiff (pore compressibilities of the order of 6 × 10-10 Pa-1) and have regional permeabilities of about 10-22 m2. In our simulations, erosion generates potential gradients that drive groundwater along deep aquifers toward regions of lowest pressure in adjacent aquitards. Groundwater, however, moves too slowly to transport a significant amount of heat. The observed west-to-east increase in the geothermal gradient across the study area most likely occurs because sediments that were deeply buried in the west are more compacted and hence more thermally conductive than those in the east.
Article
Poroelasticity theory coupled with regional groundwater flow form the basic elements of the mathematical model. It is used to predict deformation and pressure dissipation in the unfaulted and nonfolded part of a foreland basin in front of a thrust belt as it is subjected to an instantaneous loading event. Sets of numerical experiments show that overpressure zones develop along the leading edge of the thrust belt near the loading front. Stress-induced flow rates of the order of centimeters to meters per year are possible soon after compression of the foreland, and transient flow fields dissipate in about 103 and 104 years. Longer transients can exist in very low permeability strata. Large overpressues may be unable to buildup under conditions of gradual thrusting, as fluid pressures may dissipate too quickly. The general features of tectonically driven flow are also explored through a sensitivity study to consider effects of permeability, fault and stratigraphic heterogeneity, loading magnitude, and variations in rock compressibility. -from Authors
Article
The transfer of heat from the crystalline basement of sedimentary basins to the atmosphere can be influenced to different degrees by the movement of formation waters within the complex structure of aquifers and aquitards in the basin. Past studies of the geothermal regime in the Western Canada Sedimentary Basin have shown the existence of a low geothermal gradient (low heat flux area) in the foothills region of southwestern Alberta, and of a high geothermal gradient (high heat flux area) in the lowlands in northeastern Alberta, close to the Precambrian Shield. These distributions of geothermal gradients and heat fluxes were attributed to the effects of basin wide groundwater flow. Hydrogeological studies in selected parts of the basin, and dimensional analysis applied to heat transfer processes show that the permeability of the sediments, and indeed the fluid velocities, are too low to play a significant role in the transport of terrestrial heat in the Alberta part of the Western Canada Sedimentary Basin. On a regional scale, the actual distributions of the heat flux and geothermal gradients are probably due to crustal thickening and/or increased radiogenic heat generation in the basement. Thermal anomalies, which may be due to granitic intrusions, are superimposed over this trend. At an intermediate scale, the geothermal field is controlled by topography, stratigraphy, and lithology of the sediments. Only on a local scale is the convection of heat important.
Article
Zusammenfassung Grundwasserbewegungen in sedimentären Becken, die von dem topographischen Relief, konvektionsbedingtem Auftrieb, Sedimentkompaktion, isostatischen Ausgleichsbewegungen in Folge von Erosion und von Kombinationen dieser Kräfte gesteuert werden, können mit Hilfe quantitativ modellierender Techniken beschrieben werden. In diesen Modellen kann man die Auswirkungen des Transports von Wärme und gelösten Stoffen, Petroleum-Migration und die chemische Interaktion zwischen Wasser und dem grundwasserleitenden Gestein berücksichtigen.Die Genauigkeit der Modell-Voraussagen ist allerdings begrenzt wegen der Schwierigkeit, hydrologische Eigenschaften von Sedimenten in einem regionalen Rahmen vorauszusagen, dem Schätzen vergangener Bedingungen und dem Problem der Abschätzung von Wechselwirkungen physikalischer und chemischer Prozesse in geologischen Zeiträumen. Fortschritte für das Modellieren von Becken werden mit der Integration hydrologischer Forschungsanstrengungen in benachbarte Fachebiete wie Sedimentologie, Gesteinsmechanik und Geochemie zunehmen.
Article
Characterization of the spatial distribution of hydrogeologic parameters in an aquifer is important to understanding the hydrodynamics of a groundwater flow system. The operational procedure presented in this paper uses core permeability and porosity data and geophysical logs to characterize hydrogeologic parameters, especially hydraulic conductivity (K). The procedure is illustrated with a geostatistical analysis of the permeability distribution along a 120 km cross section of the Milk River aquifer in Alberta, Canada. Geologic and hydrogeologic data from aquifers come in a variety of forms. In deep, regional aquifers, the most ubiquitous form usually is geophysical logs that are used to determine spatial variations in the thickness, porosity, and permeability as well as other rock properties of hydrostratigraphic units. Several methods of deriving hydraulic conductivity values from geophysical logs are evaluated with respect to the Milk River aquifer. Based on a statistical evaluation, a direct relation between porosity and permeability was selected. Once the hydrogeologic data were analyzed and evaluated, a stochastic approach using Bayesian updating with Cholesky decomposition is used to describe the spatial heterogeneity of hydraulic conductivity. This approach produces random-correlated fields of hydraulic conductivity that are conditioned at specific locations by the geophysically derived hydraulic conductivity values. The conditioned, random-correlated fields of hydraulic conductivity are a description of relatively small-scale heterogeneity in the hydraulic conductivity field that can be used in a numerical transport model as a detailed, spatial description of hydraulic conductivity.
Article
Topographic elevation and sediment consolidation are principal components that determine pressure distribution and flow of fluids in a sedimentary basin. Although fluid flow as a result of topographic elevation can be easily simulated, porewater movement as a result of consolidation of sediment requires a physically more complex approach, as it involves sediment deformation, moving boundaries and changing sediment properties. This paper describes a mathematical model based on Terzaghi's theory of the consolidation process that calculates fluid flow as a result of consolidation, and additionally incorporates fluid flow from topographic elevation. Porosity changes are calculated as a function of fluid pressure changes, using the equation of state for porosity, thereby avoiding empirical porosity/depth formulations such as Athy's equation. It is assumed that hydraulic conductivity and sediment compressibility are reduced during consolidation, and hydraulic diffusivity remains approximately constant during the consolidation process. The permeability/porosity relation is described by the Kozeny-Carman function. The capabilities of the program are illustrated by two simple experiments.
Article
The paleohydrology of mature sedimentary basins undergoing uplift and tilting, deposition, and erosion is studied by numerically modeling the flow of variable-density ground water. In regional flow systems consisting of both shallow freshwater aquifers and deep saline aquifers, complex ground-water flow patterns can exist, when buoyancy forces dominate the hydraulic head gradients arising from topographic relief. The relative magnitude of the two driving forces, hydraulic gradient and buoyancy, changes during the hydrodynamic development of a sedimentary basin that is undergoing topographic changes. The relationship between the two driving forces and their effect on flow and transport is studied through coupled flow and solute transport simulations using an idealized model scenario. Modeling shows that increases in recharge rates can rapidly change hydrodynamic conditions from buoyancy-dominated flow governed by variable density to gravity-driven flow governed by topography. Because the dissolved mass responds much slower to changes in hydrologic boundary condition than does fluid pressure, transient conditions occur whereby the solute distribution may not correspond to the simulated ground-water flow pattern.
Article
Due to concern over the potential for widespread groundwater contamination in the sedimentary rock underlying the Niagara Falls area, this study was done to investigate the hydrogeology of the Silurian and Ordovician stratigraphy underlying the Upper Niagara River and the Eastern Niagara Peninsula. Seven boreholes (up to 150 m deep) were drilled, instrumented with multiple packer casing, tested for permeability, sampled for inorganic and organic solutes and monitored for hydraulic head to provide data for a conceptual model of regional groundwater flow. Results show that there are at least three distinct groundwater flow regimes in the bedrock. The uppermost regime consists of fracture zones in the Guelph and Lockport Formations, within which hydraulic conductivity, hydraulic head measurements and geochemical analyses indicate active groundwater circulation primarily discharging towards the Niagara Gorge and Escarpment. Underlying the Lockport Formation are an overpressured (high hydraulic head) regime in the Clinton-Upper Cataract-Lower Queenston Formation and an underpressured (low hydraulic head) regime in the Lower Cataract-Upper Queenston Formation. In both regimes, geochemical analyses and permeability measurements indicate very old and saline groundwater which probably has undergone minimal migration since pre-Pleistocene time. The implication based on the study so far, is that potential groundwater contamination below the bottom of the Lockport Formation is probably not significant in the Niagara Falls area except adjacent to the Niagara Gorge where vertical permeability in the lower flow regimes may be enhanced.
Article
Analytical data are presented for Cl, Br and I on a regional scale for the Milk River aquifer. The three halides show strikingly similar spatial distributions and are highly correlated. Concentrations are low in the freshwater portions of the aquifer but increase by as much as two orders of magnitude along the margins. However, halide ratios reach nearly constant values moving down-gradient, suggesting the dominance of a common subsurface source for these ions. Ratios of Cl/I and Cl/Br are less than those of seawater and fit an origin derived from the diagenesis of organic matter in the sediments. Halide ratios rule out leakage and/or diffusion from the underlying Colorado Group as a major influence on the chemistry; the favored hypothesis is altered connate seawater diffusing from low-permeability units within the Milk River Formation as the primary source of salts. This hypothesis of an internal source has important implications for solute sources in other aquifers affected by saline waters because it does not require the importation of a distant fluid.The129I/I ratio has a meteoric value in groundwater collected near the recharge area, but ratios for downflow waters are only 8–70% of this value. Due to the 16 Ma half-life of129I, these data indicate that most of the increase in dissolved I cannot derive from concentration of a meteoric source by ion filtration, but must have a subsurface origin. Concentrations of129I producedin situ by spontaneous fission of238U attain measurable levels only in the oldest waters sampled (ages≥ 105a), in which it may account for nearly 90% of the total dissolved129I concentration.Water ages based upon36Cl/Cl data range up to 2 Ma if uncorrected for any dilution by subsurface sources of dead Cl. If one assumes that the subsurface contributions of Cl contribute at least 90% of total Cl in the distal portion, then the36Cl-based ages are reduced to ∼ 1Ma, somewhat greater than those estimated by hydrodynamic modeling.
Article
The Milk River aquifer system consists of 30–60 m of Cretaceous sandstone located within the Milk River Formation, southern Alberta, Canada. The Milk River Formation is confined below by > 500m of shale of the Colorado Group and above by up to 120 m of shale the Pakowki Formation. The dominant recharge area for the aquifer is the Sweetgrass Hills, Montana, where the aquifer crops out. From the recharge area, the groundwater flows to the north, east and west. Calculated groundwater residence times at the north end of the aquifer (about 100 km north of the recharge area) range from 250 to 510 ka. Limited hydrological data from the confining shales suggest that cross-formational flow does not occur. Systematic patterns are observed in major ions (Na, Cl, HCO3 + CO3, and SO4), stable isotopes (18O and deuterium), and field pH on a regional scale. Several mechanisms have been proposed to explain the geochemical evolution of the groundwaters.
Article
In this study, we show how physical models describing hydrocarbon/groundwater interaction can be developed by the noble gases in the hydrocarbon phase and, based on these models, initial crustal radiogenic 4He concentrations in the associated groundwater can be calculated. Considering both in situ 4He production and 4He from an external crustal flux, this allows the 4He age of the groundwater associated with each hydrocarbon reservoir to be derived. We illustrate the strengths and weaknesses of this approach using data from case studies from the San Juan Basin coalbed methane gas field in New Mexico, USA, the Magnus oilfield in the UK North Sea and the Hugoton-Panhandle giant gas field that spans Kansas, Texas and Oklahoma, USA.
Article
The geological setup in the Powder River Basin is challenging, because of the presence of overpressured, under-pressured and normally-pressured zones with many of them saturated with oil and gas. Whereas zones of normal and abnormally-high pressure have been investigated in detail in the basin, little attention has been paid to zones of abnormally low pressure. The objective of this particular project was to test the validity of the idea that underpressured chambers have formed as a result of certain hydrothermal processes. Significant erosion or aggradation has real influence on the hydrodynamic regime, especially in the case of compacted (isolated) rocks. For estimating the thickness of eroded deposits, the authors used the method of compression curves ∗, that indicate abnormal pressure values, the presence of unconformities, and the thickness of eroded deposits near the surface and deep in the geologic section. The calculation of the influence of erosion on pore pressure in the Powder River Basin indicate the possibility of existence of underpressured zones, which are caused by significant overburden removal and temperature decrease. It is important to thoroughly investigate underpressured zones in well-studied areas of the] Powder River Basin, where newly identified types of underpressured hydrocarbon accumulations have been found. Exploration strategies can be significantly more effective if the mechanism of their formation is better understood.
Article
Full-text available
Based on analysis of groundwater hydrochemical and isotopic indicators, this article aims to identify the groundwater flow systems in the Yangwu River alluvial fan, in the Xinzhou Basin, China. Groundwater delta(2)H and delta(18)O values indicate that the origin of groundwater is mainly from precipitation, with local evaporative influence. d-excess values lower than 10% in most groundwaters suggest a cold climate during recharge in the area. Major ion chemistry, including rCa/rMg and rNa/rCl ratios, show that groundwater salinization is probably dominated by water-rock interaction (e.g., silicate mineral weathering, dissolution of calcite and dolomite and cation exchange) in the Yangwu River alluvial fan, and locally by intensive evapotranspiration in the Hutuo River valley. Cl and Sr concentrations follow an increasing trend in shallow groundwater affected by evaporation, and a decreasing trend in deep groundwater. (87)Sr/(86)Sr ratios reflect the variety of lithologies encountered during throughflow. The groundwater flow systems (GFS) of the Yangwu River alluvial fan include local and intermediate flow systems. Hydrogeochemical modeling results, simulated using PHREEQC, reveal water-rock interaction processes along different flow paths. This modeling method is more effective for characterizing flow paths in the intermediate system than in the local system. Artificial exploitation on groundwater in the alluvial fan enhances mixing between different groundwater flow systems.
Article
Formation fluid pressures are said to be anomalous or abnormal if they differ from hydrostatic for the depth considered. Explanations of the origin and maintenance of anomalies seldom include the possibility of delayed adjustment of subsurface pore pressures to erosional modifications of the topographic relief. Yet the present paper shows that it is entirely possible for subaerial erosion to generate pore pressure changes at great depths by cross-formational energy transfer in realistic field conditions. Conversely , pressures may survive changes in the topography and be in a transient state for hundreds to millions of years, thus appearing anomalous at the time of observation. According to calculations for the Red Earth region in Alberta, Canada, present pore pressures in the Devonian immediately above the Precambrian basement at a depth of approximately 1400 meters may have been induced originally by erosionally shaped topography during Pliocene times 12 to 1 m.y.B.P. but be adjusting now to new boundary conditions created by the erosional exposure of the sub-Cretaceous unconformity. A 12% adjustment may already have taken place during the last 300 thousand years, leaving nearly 90% of Pliocene age pressures to survive to date as slowly decaying transient pressure relicts of the geologic past. In view of the possible erosional effects on pore pressures demonstrated in this paper, the question of anachronous formation pressures may deserve consideration in problems related to deep basin hydrolo-gy, including regional groundwater resource development, migration and accumulation of hydrocarbons, radioactive waste isolation, dating of various geologic events, and so on.
Article
A new numerical method allows calculations of compaction-driven groundwater flow and associated heat transfer in evolving sedimentary basins. The model is formulated in Lagrangian coordinates and considers 2-D flow in the heterogeneous, anisotropic, and accreting domains. Both the continuity of the deforming medium nnd aquathermal pressuring are explicitly taken into account. The results cast doubt on roles of compaction-driven flow within intracratonic basins in processes of secondary petroleum migration, osmotic concentration of sedimentary brines, and formation of Mississippi Valley-type ore deposits. Results might also be combined with chemical models to investigate the relationship of compaction flow to cementation in sediments.-after Author
Article
Methane-rich gas is a product of low-temperature diagenesis of organic material in sedimentary rocks. The gas is generated by the degradation of organic matter in rapidly accumulating sediments by anaerobic microorganisms. The gas is referred to as biogenic gas to emphasize that biologic processes are directly responsible for its formation. Biogenic gas is generated in immature sediments and can accumulate in large quantities, and as such, it should be considered in future exploration efforts for hydrocarbons. Accumulations of biogenic gas have been discovered in Canada, Germany, Italy, Japan, Trinidad, the United States, and USSR in cretaceous and younger rocks, at less than 3350 m of burial, and in marine and nonmarine rocks. Other gas accumulations of biogenic origin have undoubtedly been discovered; however data that permit their recognition are not available. (JMT)
Article
Using coal rank data and the demonstrated genetic link between the present hydrodynamic regime and geothermal gradient pattern, it is possible to reconstruct the geothermal history of Alberta over the past 60 m.y. Palinspastic adjustment for tectonic compression caused by the major Laramide thrusting shows that the predeformation isoreflectance lines increased logarithmically with depth. In the late Paleocene, the geothermal gradient was about 23°C/km (1.25°F/100 ft) in the eastern Alberta Plains, compared to about 30°C/km (1.65°F/100 ft) in the western Alberta Plains, a regional trend opposite to the postLaramide trends. Reconstruction of the early Eocene surface indicates western uplands with geothermal gradients as low as 21°C/km (1.15°F/100 ft) and eastern lowlands with geothermal gradients of 27°C/km (1.5°F/100 ft). Compared to the present situation, this represents an enhanced topographic surface and a subdued geothermal gradient pattern. (The genetic relations of topography (water-table elevation), hydrodynamic regime, and geothermal gradient pattern in both the early Eocene and the present conform to a model developed for any compacted sedimentary basin with subaerial relief.) In this model, (On a regional scale, high topographic areas have high water-table elevations with correspondingly high potentiometric surfaces; these areas control the regional recharge of cold meteoric water and hence have low geothermal gradients. Areas of medium elevation exhibit regional lateral flow and intermediate geothermal gradients. Regional topographic lows correspond with low potentiometric surfaces,) and the regional discharge of warm formation waters from deep in the basin results in high geothermal gradients.
Article
Many of the mountain ranges in western Montana, and the adjoining intermontane basins, are interpreted as chiefly the effects of block faulting like that in the Great Basin. The region was elevated above the sea in late Cretaceous or early Tertiary time; then followed a long period of crustal stability in which a great thickness of rocks was eroded. By Oligocene time the region had been generally reduced to a surface of moderate to slight relief. During the Oligocene and Miocene the drainage became sluggish or ponded, chiefly because of slow crustal movements that outlined the present basins and ranges. Areas corresponding approximately to the present basins became depressed, and in these accumulated the Tertiary "lake beds." Areas of uplift corresponding to the present mountains were eroded and thus contributed land waste and volcanic ash to the "lake beds." In the late Miocene or early Pliocene the surface comprised areas of older rocks that, except for scattered residual peaks and ridges, had been eroded to slight or moderate relief; and areas of the "lake beds" that formed gently sloping or level plains. Excluding the residuals, this surface is called here the Late Tertiary peneplain. Further leveling of the older rock areas and deposition of the "lake beds" was interrupted by a general re-elevation of the region accompanied by greatly accelerated local crustal movements that relatively elevated the present mountains. These movements continued intermittently and with decreasing intensity through the Pliocene and, except for small displacements on some of the faults as late as the Recent epoch, ceased in early or middle Pleistocene. They are thought to constitute a distinct late stage of the Cenozoic mountain building. During the halt in the uplift of the mountains, wide stream valleys as much as 1500 feet deep were eroded in the elevated and deformed peneplain. In the basins during this pause, called the Old Valley cycle, the "lake beds" were reduced to gently sloping plains collectively referred to as No. 1 Bench. With renewed uplift the more vigorous streams deepened their channels across the mountain blocks as fast as the surface rose and thus excavated narrow inner valleys or gorges. In this, the Present cycle of erosion, No. 1 Bench of the "lake bed" areas was, in most of the basins, dissected to a series of terraces. The faulting appears to be indirectly related to an axis of compression trending northwestward from Yellowstone National Park. Horizontal compressive forces moved opposite parts of a deeply buried layer of the earth's crust toward this axis. Relief from the compression raised the overlying layer thus causing tensional strains that were relieved by normal faulting and movements away from the plane of the axis.
Article
When rocks deform in response to changes in stress, the small variations in pore volume that occur affect the pore fluid pressure. The changes in fluid pressure can be significant if the rate of change of stress is large relative to the rate at which pressure perturbations are dissipated by flow. It has been proposed previously that the gradually increasing loads on sediments undergoing burial can cause excess fluid pressures. We hypothesize that the opposite effect, depression of pore pressure resulting from rebound during erosional unloading, also may occur in certain geologic settings. It appears that a mechanism exists for generating significant underpressuring and unsaturated conditions below the water table in thick sequences of poorly permeable rock. The analysis also shows that in formations with depressed fluid pressures the groundwater flow is inward from the permeable boundaries for long periods of time. These results may be of importance it toxic materials are to be isolated in 'tight' rocks.-Authors
Article
Details of steady-state flow in regional groundwater basins can be investigated using digital computer solutions of appropriately designed mathematical models. The factors that must be considered are: (1) ratio of depth to lateral extent of the basin; (2) Watertable configuration; and (3) stratigraphy and resulting subsurface variations in permeability. The results of this study provide a theoretical basis for the following properties of regional flow systems: (1) groundwater discharge will tend to be concentrated in major valleys; (2) recharge areas are invariably larger than discharge areas; (3) in hummocky terrain, numerous sub-basins are superposed on the regional system; (4) buried aquifers tend to concentrate flow toward the principal discharge area, have a limiting effect on sub-basins, and need not outcrop to produce artesian flow conditions; (5), stratigraphic discontinuities can lead to distributions of recharge and discharge areas that are difficult to anticipate and that are largely independent of the water-table configuration. (Key words: Groundwater; computers, digital; drainage basin characteristics)
Readily available laboratory, in situ, and inferred values of permeability, k, of crystalline and argillaceous rocks have been compared. For crystalline rocks, in situ k ranged from about 1 mu d (10-14 cm2) to 100 md; for argillaceous rocks it was about 0.01 to 1 mu d. -from Author
Article
The Milk River artesian aquifer underlines an area of approximately 6300 km2 in southern Alberta. This aquifer fits almost exactly Chamberlain's (1885) concept of a classic artesian system. It crops out or is covered by a thin veneer of glacial drift in southern Alberta and northern Montana. It is believed that major recharge occurs in these areas (Meyboom, 1960). Structurally, the aquifer appears fan-like in form, dipping gently to the east, north and west from its areas of outcrop. It is overlain by the Pakowki Formation which is a grey shale that acts as a confining bed. Analysis of stable isotope and major ion data for water samples collected from the aquifer reveals a variety of striking patterns. Oxygen-18 and deuterium concentrations for groundwater from the recharging portion of the aquifer fall very close to the meteoric water line (Craig, 1961a) indicating that they are isotopically unaltered meteoric waters. Proceeding down-dip in the aquifer groundwaters become enriched isotopically to a maximum of 70 and 12‰ with respect to deuterium and oxygen-18 in the recharging waters. In addition, a systematic deviation (slope of 6.1 instead of 8) from the meteoric water line is also apparent. The most plausible explanation of these isotopic patterns is based on a process of dispersion or mixing on a regional scale. Waters probably enriched with respect to the isotopic composition of the aquifer recharge may be present and simply are being displaced by meteoric water, or leakage may have entered the aquifer from below progressively comprising an increased proportion of the aquifer water. This same type of mixing process appears to exert a major control on the major ion chemistry of the aquifer. In addition, chemical processes such as mineral dissolution and cation exchange play a role.
Article
Isotopic and major-ion analyses of 130 fresh and brackish groundwater samples reveal a strikingly consistent pattern of variation over 28,000 km2 of the western Canada sedimentary basin. Hydrodynamic interpretations based on drill-stem tests and piezometric data reveal a pattern of broad, regional flow from south to north. However, there is some evidence to suggest that patterns of groundwater flow have been influenced in the past by Wisconsin glaciation. All the permeable units appear to be recharged by meteoric water in the south where they outcrop or come close to the surface. Samples of groundwater collected down dip in each of six major sandstone units are progressively enriched in D, 18O, Na+ and Cl−. For example, the deepest waters of the artesian Milk River aquifer are enriched by up to 70‰ and 15‰ with respect to the δD and δ18O of the modern recharge waters. The pattern of chemical evolution is strongly related to the hydraulic characteristics of individual units. The isotopic composition is determined by the extent to which hydraulic conductivity has facilitated meteoric water flushing of connate water. Thus, more permeable units and permeable zones within a unit tend to be isotopically lighter because of a more complete and more rapid invasion of meteoric water. Interestingly, the largest conductivity values are found in some of the deepest units (1500 m). Consequently, water in these deeper units have δD- and δ18O-values which approach that of the recharge. The major-ion chemistry is controlled both by this process and a complex set of rock-water interactions. In addition to providing information about the chemical evolution of groundwater, this study can begin to quantify the complex pattern of flushing in a large sedimentary basin.
Chapter
Various physical and chemical processes may be envisioned which will cause anomalous pressures on an underground fluid. In order to consider the maintenance of anomalous pressure, it is necessary to consider the problem as one of nonsteady fluid flow. The time rate of pressure change and maintenance depends upon the hydrodynamics of flow through porous media and the particular boundary conditions. This paper presents a series of general solutions to hydrodynamic models which are germane to the problem of creating and maintaining excess-fluid pressures in a thick sedimentary sequence. The creation and maintenance of fluid pressures approaching lithostatic pressure through a process of continuous sedimentation was evaluated. Our results indicate that a sedimentation rate of 500 m/106 yr (reasonable for the Gulf Coast) will create fluid pressures approaching lithostatic in a sedimentary column that has a hydraulic conductivity of 10-8 cm sec-1, or lower. It is apparent that the creation of anomalous pressure and its maintenance depends, to a large degree, upon the hydraulic conductivity and, to a lesser extent, upon the specific storage of clay layers within the system.
Article
181-210 http://deepblue.lib.umich.edu/bitstream/2027.42/48308/2/ID148.pdf
Structure, seismic data, and orogenic evolution of southern Canadian Rocky Mountains
  • A W Bally
  • P L Gordy
  • G A Stewart
Bally, A.W., Gordy, P.L. and Stewart, G.A. 1966. Structure, seismic data, and orogenic evolution of southern Canadian Rocky Mountains. Bulletin of Canadian Petroleum Geology, v. 14, p. 337-381.
Abnormal formation pressures. American Association of Petroleum Geologists Bulletin, v. 59
  • J S Bradley
Bradley, J.S. 1975. Abnormal formation pressures. American Association of Petroleum Geologists Bulletin, v. 59. p. 957-973.
Selected methods for pun~ping test analysis. Illinois State Water Survey
  • J Bruin
  • H E Hudson
Bruin, J. and Hudson, H.E. Jr. 1961. Selected methods for pun~ping test analysis. Illinois State Water Survey, Report of Investigation 25, 54p.
The Flaxville Gravel and it~ relation to other terrace gravels of the Northern Great Plains. United States Geological Survey
  • A J Collier
  • W T Thom
Collier, A.J. and Thom, W.T. 1918. The Flaxville Gravel and it~ relation to other terrace gravels of the Northern Great Plains. United States Geological Survey, Professional Paper 108-J, p. 125-184.
Cenozoic history of northwestern Montana and northeastern North Dakota with emphasis on the Pleistocene. United States Geological Survey Professional Paper 326
  • D A Howard
Howard, D.A. 1960. Cenozoic history of northwestern Montana and northeastern North Dakota with emphasis on the Pleistocene. United States Geological Survey Professional Paper 326, 108 p.
Study of the hydrodynamic pattern in a sedimentary basin subject to subsidence. Preprint, paper no. SPE 2988, prepared for the 45th Annual Fall Meeting of the Society of Petroleum Engineers of A1ME
  • C Jacquin
  • M J Poulet
Jacquin, C. and Poulet, M.J. 1970. Study of the hydrodynamic pattern in a sedimentary basin subject to subsidence. Preprint, paper no. SPE 2988, prepared for the 45th Annual Fall Meeting of the Society of Petroleum Engineers of A1ME, Houston, Texas, Oct. 4-7, 6p. _ _ and 1973. Essai de restitution des conditions hydrodynamiques r6gnant dans un bassin s6dimentaire au cours de son 6volution. Revue de l'Institut Francais du P6trole, v. 27, no. 3, p. 269-297.
Review of Basic Formation Evaluation
  • Johnston Testers
Johnston Testers. 1964. Review of Basic Formation Evaluation. Houston, Texas, 2p.
Report on the Cypress Hills Wood Mountain and adjacent country. Geological and Natural History Survey of Canada
  • R G Mcconnell
McConnell, R.G. 1886. Report on the Cypress Hills Wood Mountain and adjacent country. Geological and Natural History Survey of Canada, Annual Report, v. 1, 1885, p. IC-85C.
Geological History of Western Canada
  • R G Mccrossan
  • Glaister
McCrossan, R.G. and Glaister, R.P. (Eds.) 1964. Geological History of Western Canada, Calgary, Alberta Society of Petroleum Geologists, 232p.
Geology and groundwater resources of the Milk River Sandstone in southern Alberta. Research Council of Alberta
  • P Meyboom
Meyboom, P. 1960. Geology and groundwater resources of the Milk River Sandstone in southern Alberta. Research Council of Alberta, Memoir 2, 89p.
Basement control of Cretaceous sand sequences in Western Canada. Geological Association of Canada
  • C R Stelck
Stelck, C.R. 1975. Basement control of Cretaceous sand sequences in Western Canada. Geological Association of Canada, Special Paper 13, p. 428-439.
A theoretical analysis of groundwater flow in small drainage basins
A theoretical analysis of groundwater flow in small drainage basins. Journal of Geophysical Research, v. 68, no. 16, p. 4795-4812. 1978. Gravity-induced cros s-formational flow of formation-fluids, Red Earth region, Alberta, Canada: Analysis, Patterns, and Evolution. Water Resources Research, v. 14, p. 805-843.
Cross-formational gravity-flow of groundwater: a mechanism of the transport and accumulation of petroleum (the generalized hydraulic theory of petroleum migration)
_ _ 1980. Cross-formational gravity-flow of groundwater: a mechanism of the transport and accumulation of petroleum (the generalized hydraulic theory of petroleum migration). American Association of Petroleum Geologists, Studies in Geology 10: Problems of Petroleum Migration, p. 121-167.
The development of the Sweetgrass Arch, southern Alberta
  • W M Tovell
Tovell, W.M. 1958. The development of the Sweetgrass Arch, southern Alberta. Proceedings of the Geological Association of Canada, v. 10, p. 19-30.
Surficial geology of the Foremost -Cypress Hills region
  • J A Westgate
Westgate, J.A. 1968. Surficial geology of the Foremost -Cypress Hills region, Alberta. Research Council of Alberta, Bulletin 22, 122p.
The physiography of the southwestern plains of Canada. Proceedings and Transactions of the Royal Society of Canada
  • M Y Williams
Williams, M.Y. 1929. The physiography of the southwestern plains of Canada. Proceedings and Transactions of the Royal Society of Canada, v. 23, p. 61-79.
Physiography and glacial geology of eastern lVlontana and adjacent areas. United States Geological Survey
  • W C Alden
Alden, W.C. 1932. Physiography and glacial geology of eastern lVlontana and adjacent areas. United States Geological Survey, Professional Paper 174, 133p.