
Kevin M BohacsKMBohacs GEOconsulting · Hydrocarbon Systems and Stratigraphy and Safety
Kevin M Bohacs
Sc. D. in Experimental Sedimentology
About
143
Publications
59,394
Reads
How we measure 'reads'
A 'read' is counted each time someone views a publication summary (such as the title, abstract, and list of authors), clicks on a figure, or views or downloads the full-text. Learn more
6,622
Citations
Introduction
Publications
Publications (143)
Overview presentation of containment aspects of Geological Carbon Sequestration at different time scales and for different site styles
The sedimentary fill of Gale crater on Mars is dominated by lacustrine strata that are the focus of investigations into surface processes, climate change and habitability early in the planet's history. This study focuses on the lower part of the explored portion of the Murray formation on Aeolis Mons (Mount Sharp) in the Pahrump Hills and Hartmann'...
The lake‐basin‐type model classified the stratigraphic record of ancient lake systems according to rates of potential accommodation relative to sediment + water supply. The model convolved all modes and paths of water supply (direct fall, surficial, subsurface) with amounts and types of sediment supply (clastic, biogenic, chemical) into a single ba...
With some exceptions, such as fluid phase, pressure evolution, and reservoir geometry, evaluation of CO 2 retention for geological sequestration sites primarily involves well-established seal and trap concepts and methods developed by the petroleum industry. Inputs to a CO 2 retention evaluation (e.g., bed seal capacity analysis) include CO 2 phase...
The Santa Clara Abajo and Santa Clara Arriba formations host a diverse assemblage of trace fossils that record a wide range of behaviors and a broad array of ecological niches during the Middle Triassic, a critical period in the evolution of continental fauna with the diversification of both synapsids (cynodont and dicynodont) and archosauromorphs...
The application of biostratigraphic studies in the energy and subsurface-storage industries. An example from the Ainsa Basin, Spain
Biostratigraphic studies are commonly used in the oil industry for age calibration and facies characterization. Particularly in fine-grained sedimentary successions, integration of biostratigraphic data with sequence-...
The application of biostratigraphic studies in the energy and subsurface-storage industries. An example from the Ainsa Basin, Spain
LEON-RODRIGUEZ Lizette, JONK Rene, KNABE Keith, KEVIN BOHACS Kevin and DAVIS J. Steve
Biostratigraphic studies are commonly used in the oil industry for age calibration and facies characterization. Particularly in fi...
The Late Devonian Canol Formation and associated stratal units in the Northwest Territories of Canada illustrate the expression of sequence-stratigraphic surfaces and units in a distal Paleozoic carbonate shelf to relatively deep-basin setting. These Devonian strata are time equivalent and quite analogous in depositional conditions and petroleum-sy...
The Cretaceous Mowry Shale and associated units in the Bighorn Basin of Wyoming,
illustrate the expression of sequence-stratigraphic surfaces and units in a Mesozoic epeiric sea in a proximal to distal, detrital-to-biogenic–dominated shelf setting. Associated units include the Muddy Sandstone, Belle Fourche Shale, and Frontier Formation and are of...
Workflows for assessing long-term containment of CCS sites
Although the adage “the rocks don’t lie”is true—rocks are literal ground truth—their message can be misinterpreted. More generally, it is misguided to favor one form of inquiry, such as field observation, over others, including laboratory analyses, physical experiments, and mathematical or computational simulations. This was recognizedmore than a c...
Geological Carbon Sequestration (GCS) needs to increase in scale by a hundred to thousand-fold to achieve the climate targets set out by the 2015 Paris Agreement. As such, assessment of storage potential and containment risk is required across many types of subsurface opportunities (including depleted fields and saline aquifers). In particular, the...
The Monterey Formation is a Miocene marine unit that occurs extensively in the Coast Ranges and in the continental margins of California, and analogous biosiliceous deposits are found around the Pacific Rim and elsewhere in the world. Classic studies on the diatomaceous deposits that characterize the hemipelagic/pelagic facies of the Monterey Forma...
Mudstone‐dominated lacustrine strata in the Pahrump Hills area of Gale Crater, Mars, have the most extensive data set of physical and geochemical observations yet collected. Although sparse by Earth standards, a source‐to‐sink portrayal of the sedimentary system that differs substantially from previous work has been extracted by integrating sedimen...
Showcase well-known workflows for evaluating capillary retention and leakage of hydrocarbon fluids in the subsurface to the problem of evaluating caprock characteristics and containment risk for CCUS projects.
Mudstone-rich lacustrine strata at Gale Crater, Mars, dominate the Mt. Sharp sedimentary succession. The Gale crater strata provide the oppor-tunity to test hypotheses regarding past climate shifts early in the planets history [1, 2], a key motivator for selecting Gale Crater as a landing site for the Curiosity rover.
At the base of the Mt. Sharp s...
Assessing long-term containment riks for geological carbon sequestration sites
The late Middle Devonian Geneseo Formation and its lateral equivalents in the northern Appalachian Basin are significant secondary targets to the extensively explored Marcellus Sub-group. Surface to sub-surface characterization of the mudstone-dominated Geneseo Formation combines detailed observations of facies, facies associations, stratal archite...
A recent presentation outlining workflows in capillary seal evaluation at rock, log and seismic scales with application to understanding geologic carbon sequestration.
The Kimmeridge Clay Formation of the Wessex Basin, United Kingdom, illustrates the expression of sequence-stratigraphic surfaces and units in a relatively restricted Mesozoic clastic shelf to relatively distal basin setting. This formation is of similar age and depositional setting to the Haynesville Formation (USA), Vaca Muerta Formation (Argentin...
The Monterey Formation illustrates the expression of sequence-stratigraphic surfaces and units in continental slope and basin settings that are quite unlike those of most mudstone units considered thus far in this book. These strata span a wide variety of siliceous, calcareous, argillaceous, phosphatic, and kerogenous composition, detrital, biogeni...
The Green River Formation illustrates the expression of sequence-stratigraphic surfaces and units in lacustrine and alluvial strata. These settings are distinctly different from those of most of the mudstone units considered in this book. Our study shows how applying the sequence-stratigraphic method and approach from first principles in continenta...
This chapter introduces the key aspects of mudstone and the naming scheme we recommend and use when characterizing mudstone in outcrops, cores, and thin sections. This naming scheme is based on three key rock attributes: texture, bedding, and composition. This scheme has been designed to enable textural (grain size), bedding, compositional, and gra...
This chapter presents definitions, recognition criteria, and examples of parasequence sets, depositional sequences, and their key defining surfaces to be applied within the overall sequence-stratigraphic workflow. This scale of stratification is most useful for correlating and mapping across large areas of basins and for understanding and predictin...
Fine-grained sedimentary rocks (e.g., shale, mudrock, mudstone, claystone, chert, or chalk) are the most common rocks in the stratigraphic column. They preserve the best archives of Earth’s history for interpreting paleoclimate and paleo-oceanography; influence the flow of groundwater and hydrocarbons; serve as hydrocarbon source, reservoir, and se...
This chapter illustrates the expression of sequence-stratigraphic units and surfaces in the Paleozoic, relatively shallow-water carbonate-dominated setting of the Chimney Rock and associated members of the Paradox Formation, Paradox basin, Utah. These Pennsylvanian source rocks and reservoirs form part of the petroleum system of the billion-barrel...
This chapter discusses the smaller scales of the stratal hierarchy—from lamina to bedset. In mudstone, these typically range from less than a millimeter to hundreds of millimeters in thickness. This is the scale of strata that records individual depositional events and environmental changes in bottom energy, biogenic production rates, and redox con...
This chapter presents parasequences—the next larger and more aerially extensive three-dimensional stratal unit of the stratigraphic hierarchy found consistently across most depositional environments. The parasequence scale is the key scale at which we interpret depositional environments, apply Walther’s Law to recognize significant stratal disconti...
Mudstone properties vary widely, but systematically, both vertically and laterally at millimeter-to-kilometer scales. This variability can be detected by applying a range of physical, petrophysical, chemical, and paleontological methods to characterize the rocks at different scales and interpreting the resulting data using the sequence-stratigraphi...
This chapter presents definitions, recognition criteria, and examples of sequence sets and composite sequences within a sequence-stratigraphic framework. This stratigraphic scale provides useful insights into shale-gas and tight-liquid plays with mudstone reservoirs that can be profitably grouped into four families based on stratal stacking at the...
This chapter addresses controls on the stratigraphic record: the mechanisms, processes, and contingencies affecting sediment supply and accommodation and the resulting stratal surfaces and units. Although it is not necessary to know the forcing mechanisms of sequence formation to construct a sequence-stratigraphic framework and map the distribution...
The Upper Pleistocene to Holocene (post-last glacial maximum) succession of the Po River Plain, northern Italy, illustrates the expression of sequence-stratigraphic surfaces and stratal units in paralic and coastal-plain settings that are different from the settings of most of the mudstone units considered thus far in this book. This interval spans...
Continental shelves host 90% of modern Organic Carbon (OC) burial and play a key role in the sequestration of
terrigenous OC over geological timescales. The efficiency of OC burial in these systems, however, varies greatly
depending on the duration of exposure to oxic-suboxic conditions during sediment transport. In this study, we
use observatio...
Reconstructing continental paleoenvironmental conditions (temperature, precipitation, hydrology, and hydrography) is essential for constraining the influences on terrestrial ecosystems, sediment and solute yields to the ocean and carbon cycles, as well as for calibrating numerical paleoclimate models. Making such reconstructions from lacustrine str...
Discerning paleoclimate parameters in depositional systems of the continental interior is challenging because the system response and stratigraphic record of climate are controlled by tectonic processes and are mediated through landscape and hydrological evolution of fluvial lacustrine systems. Climate and tectonic signals cannot be deconvolved fro...
Quantification of the interaction between river discharge and tides is vital to characterize fluvio-deltaic systems, to identify diagnostic elements of tidal signatures in the rock record, and to reconstruct paleogeographies. In modern systems, even microtides can significantly influence delta morphodynamics; yet, many fundamental processes, partic...
Sequence stratigraphy, typically used for hydrocarbon exploration in ancient strata, can be applied to late Quaternary successions to decipher complex spatial relations among their aquifers.
Late Pleistocene–Holocene strata of the Po Basin were investigated using a sequence stratigraphic approach to produce a highresolution model for guiding ground...
Fundamental concepts of plate tectonics, palaeogeography, ecology, and atmospheric and oceanic circulation can be used in conjunction with models of source rock deposition to understand the location and character of organic matter–rich rocks (ORRs) at global to regional scales. Ocean and atmosphere circulation patterns directly impact processes gov...
Clinoforms with a range of scales are essential elements of prograding continental margins. Different types of clinoforms develop during margin growth, depending on combined changes of relative sealevel, sediment supply and oceanographic processes. In studies of continental margin stratigraphy, trajectories of clinoform “rollover” pointsare often u...
Reconciling interpretations of geochemical, sedimentologic, and stratigraphic observations is a common challenge with many datasets, especially those from paleolake systems. The Triassic Cerro de las Cabras and Cerro Puntudo formations, part of the sedimentary fill of the Cuyana rift Basin in central-west Argentina, represent carbonate-rich playa-l...
Although general trends in transgressive to highstand sedimentary evolution of river‐mouth coastlines are well known, the details of the turnaround from retrogradational (typically estuarine) to aggradational–progradational (typically coastal/deltaic) stacking patterns are not fully resolved. This paper examines the middle‐late Holocene eustatic hi...
Even in a system whose stratal record is well expressed, it can be challenging to confidently differentiate sequence boundaries from other erosional surfaces because of lateral changes in stratal patterns due to variations in accommodation and sediment-supply rates and routes. Identifying a sequence boundary, as originally defined by Mitchum et al....
Sequence stratigraphy is a method to systematically place key stratal observations into a chronostratigraphic framework for more accurate predictions away from control points. The depositional sequence is its basic unit, defined as “a stratigraphic unit composed of a relatively conformable succession of genetically related strata and bounded at its...
The vastness of time is largely beyond human observation, but how aware are most geologists of the concept of time? Time spans of just a few thousands of years may become unfamiliar when moving from the modern, observable, and quantifiable, sedimentary processes acting on decadal to centennial time scales to the intricate series of depositional eve...
Although facies and stratal geometries of continental margin successions can be defined in detail based on subsurface and outcrop studies, most studies lack the high-resolution age control needed to constrain the time scale of formation of such successions and infer their external forcing mechanisms. Our work on the P...
Even in a system whose stratal record is well expressed, it can be challenging to confidently differentiate sequence boundaries from other erosional surfaces because of lateral changes in stratal patterns due to variations in accommodation and sediment-supply rates and routes. Identifying a sequence boundary, as originally defined by Mitchum et al....
Abstract available online at http://www.icfscalgary.com/images/ICFS_11_Programme_and_Abstracts_V2A.pdf
To understand the complex stratigraphic response of a coastal depositional system to rapid eustatic rise and sediment inputs, the evolution of the Adriatic coastline and Po River system, during the post-glacial (Holocene) transgression, was investigated. The landward migration and evolution of a wave-dominated estuary was mapped, based on an extens...
In siliciclastic marine settings, skeletal concentrations are a characteristic feature of transgressive intervals that provide insights into biological and sequence-stratigraphic processes. To investigate taphonomic signatures of transgressive intervals, we analyzed three cores along a depositional profile from the high resolution chrono- and strat...
The 350-m-thick succession of the Po River lowstand wedge (Italy) associated with the Last Glacial Maximum (deposited over ∼17 k.y) contains stratal architecture at a physical scale commonly attributed to much longer time scales, with complex, systematically varying internal clinothem characteristics. This study investigated clinothem stacking patt...
Holocene deposits exhibit distinct, predictable and chronologically constrained facies patterns that are quite useful as appropriate modern analogs for interpreting the ancient record. In this study, we examined the sedimentary response of the Po Plain coastal system to short-term (millennial-scale) relative fluctuations of sea level through high-r...
In siliciclastic marine settings, skeletal concentrations are a characteristic feature of transgressive intervals that provide insights into paleobiology and sequence stratigraphy. To investigate taphonomic signatures of transgres-sive intervals, we analyzed three cores from a Holocene depositional profile of the Po coastal plain, in northern Italy...
The future of sequence stratigraphy depends on stratigraphers making observations with a common method so that physical frameworks can be clearly separated from interpretations of driving mechanisms. Depositional sequence boundary selection is a well-known controversy that could be resolved with objective recognition criteria. Accommodation success...
In the marine realm, condensed deposits form in a variety of settings affected by sediment bypassing or sediment starvation. In siliciclastic marine settings skeletal concentrations are a diagnostic feature of condensed intervals and are of high relevance to sequence stratigraphy and paleobiology. Here, using three fossiliferous cores, we investiga...
Foundational principles and defining criteria of both sequence stratigraphy and lake basin type (LBT) analysis are essentially geometric, without reference to mechanism of formation or the value of g. Hence both approaches should be applicable to strata on other planets. The similarity of fractal dimensions of lake-basin area, volume, and mean dept...
As the exploration of unconventional plays continues to expand into increasingly challenging geologic environments the ability to predict the distribution of high reservoir quality has become an area of active research. Strata deposited around the Cenomanian – Turonian (C-T) boundary have received particular attention globally. Widely regarded as o...
A method for retrodicting source-rock quality and/or paleoenvironmental conditions are disclosed. A first set of system variables associated with source-rock quality is selected (705). A second set of system variables directly or indirectly causally related to the first set of variables is also selected (710). Data for variables selected to be know...
An integrated nomenclature scheme is proposed to capture the inherent heterogeneity of fine-grained sedimentary rocks at the 10(2) to 10(-3) mm scale and to assist the evaluation of these rocks as sinks of organic carbon, barriers to fluid flows, and reservoirs of oil and gas. This scheme incorporates previous knowledge and the latest field, petrog...
All attempts to " codify " Sequence Stratigraphy have failed, from the first effort of the North American Commission on Stratigraphic Nomenclature in the 80's to the more recent endeavor by the International Subcommission on Stratigraphic Classification in Europe. Reasons for not including Sequence Stratigraphy in the stratigraphic code vary. Compl...
Method for assessing hydrocarbon source rock potential of a subsurface region without well log information. The method uses surface electromagnetic (121) and seismic (122) survey data to obtain vertical profiles of resistivity and velocity (123), which are then analyzed in the same way as well log data are analyzed by the well known Delta Log R met...
strata have a vast variety of physical, biogenic, and chemical attributes at the lamina to bed scale (approximately millimeters to decimeters thick). Our observations of more than 7 km of Paleozoic to Cenozoic mudstones revealed ordered patterns in this variety, i.e., recurrent associations of lithofacies, bedding style, sedimentary structures, and...
Lacustrine carbonate lithofacies in the Hot Spring limestone vary systematically at meter to decameter scales and record paleobathymetry, limnologic conditions, and paleogeographic influences. This unit accumulated during the late Miocene in a lake system in an extensional basin complex, closely associated with lava flows and volcanidastics. Sedime...
A spectrum of combinations of rock and hydrocarbon properties in fine-grained rocks can result in significant production, effectively spanning ‘conventional' tight oil to fractured ‘shale' gas reservoirs, in four main families based on dominant porosity-permeability system and stratal relations (i.e., ‘Conventional' tight, Hybrid/Interbedded, Porou...
A spectrum of combinations of rock and hydrocarbon properties in fine-grained rocks can result in significant production, effectively spanning 'conventional' tight oil to fractured 'shale' gas reservoirs, in four main families based on dominant porosity-permeability system and stratal relations (i.e., 'Conventional' tight, Hybrid/Interbedded, Porou...
The Late Cretaceous Mowry interval of the present day Big Horn Basin records deposition in the proximal to medial portion of the Western Interior Seaway under systematically variable conditions of organic-matter production, preservation, and dilution. These variations control the quality and distribution of key play elements throughout the basin. A...
Recent studies of marine shelf sediment dispersal show that wave-enhanced sediment-gravity flows are widespread phenomena and can transport large volumes of fluid mud rapidly across low-gradient shelves. Flow evolution is controlled by sediment supply, seabed gradient, and spatial distribution of wave energy at the seabed. Using existing flow model...
Many currently producing shale-gas reservoirs are overmature oil-prone source rocks. Through burial and heating these reservoirs evolve from organic-matter-rich mud deposited in marine, lacustrine, or swamp environments. Key characterization parameters are: total organic carbon (TOC), maturity level (vitrinite reflectance), mineralogy, thickness, a...
Shale successions are typically heterogeneous at various vertical and lateral scales. The construction of earth models (basin and reservoir models) requires a detailed analysis of rock properties within a sequence stratigraphic framework that typically integrates observations at mm- to m- to km-scales. Earth models (basin and reservoir models) that...
Thesis (Sc. D.)--M.I.T., Dept. of Earth and Planetary Science, 1981. Supervised by John B. Southard. Vita. Bibliography: leaves 170-178.
Innovations in paleo-environmental reconstructions can play an important part in the exploration needed to meet the world's growing demand for sufficient and reliable energy. We have developed new technology which integrates the complex interactions among numerous paleoenvironmental controls to predict the occurrence, quality, and distribution of s...