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Horizontal permeability for the sequence (from NMR log of Bore G). Both the underlying Gellibrand Marl and the overlying Hanson Plain Sand are virtually impermeable. Within the Port Campbell Limestone, permeability in the uppermost subcycle of each depositional cycle increases up-sequence. The surface fault trace is projected up from the top of the Port Campbell Limestone.
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CO2CRC is undertaking a feasibility study for a planned CO2 controlled release and monitoring experiment on a shallow fault at the CO2CRC Otway Research Facility. In the first phase of the project, a series of geophysical surveys and groundwater permeability assessments were conducted at the Otway Research Facility to characterise the prospective e...
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Context 1
... depositional cycles have been interpreted within the Port Campbell Limestone sequence and within each cycle permeability is highly variable, ranging from marly carbonate of poor permeability to an uppermost porous and permeable bioclastic grainstone interval (Fig 6). The top of the Port Campbell Limestone is regarded as a significant unconformity with karst development and an accumulation of a residual iron-rich regolith. ...
Citations
... Injection experiments have confirmed that faults are the main leakage zones when the host rock has very low porosity and permeability (Ciotoli et al., 2005;Lombardi et al., 2008). More recently, deeper injection tests have been performed at the CSIRO in-Situ Laboratory (Michael et al., 2020, and references therein), the Otway National Research Facility in Victoria (Feitz et al., 2018(Feitz et al., -2022Tenthorey et al., 2019), and the Mont Terri underground rock laboratory in NW Switzerland (Zappone et al., 2021). ...
... The aim is to simulate a gaseous CO2 mass, that is rising from the depth, as is used to do in the experimental apparatus through a shallow injection well. In this way our injection points also simulate the bottom of this well located at a depth of about 80 m below ground level, for all the investigated scenarios and in accordance with real experiments and fluid models about shallow injection conditions performed in fault zone (e.g., Plaisant et al., 2018;Feitz et al., 2018Feitz et al., , 2022. The total injection time was set to 100 days, to provide enough time for the gas to migrate in the domain. ...
We integrated geological and 2D basin modelling to investigate the tectonostratigraphic evolution of the East Beni Suef Basin (EBSB) of north central Egypt and its implications for the Upper Cretaceous petroleum system. Two intersecting seismic sections and three exploration wells were used for this study. The geological model defines the structural and geometrical framework of the basin, which formed the basis for subsequent 2D basin modelling. The developed basin models were calibrated and fine-tuned using vitrinite reflectance and corrected temperature data. Modelling results indicate that the Abu Roash ‘F’ source-rock maturity ranges from the early oil window at the basin margins to the main oil window in the centre. The main phase of hydrocarbon generation occurred during the Eocene after trap formation in the Late Cretaceous. Generated hydrocarbons have migrated both laterally and vertically, most likely from the central part of the basin towards the basin margins, particularly eastwards to the structural traps. The model predicts low accumulation rates for the EBSB, which are caused by the ineffective sealing capacity of the overburden rocks and normal faults. In addition to the proven kitchen for the charging of the Abu Roash ‘E’ reservoirs, an additional kitchen area to the NW of the basin is suggested for the Abu Roash ‘G’ reservoirs.
... Refraction seismic modelling (Feitz, Radke, et al., 2018) suggests that the fault follows a pervasive joint fabric, with intervening jogs of 30 departure ( Figure 8). Across the CO2CRC site, several paralleling dislocations were detected, showing the pervasive effects of stress and weathering on the sequence. ...
... These are inferred to extend laterally in the near-surface weathering that has been influenced by jointing (Figure 8), as well as further down sequence in closer proximity to the Brumbys Fault. Anomalous lower seismic velocities near surface and near fault were defined in the geological model of Feitz, Radke, et al. (2018). This would suggest that the fault and comparative fractures have been influential in locally channelling groundwater along structures, enhancing dissolution as well as dolomitisation. ...
... The possible condensation of the upper sequence by dissolution processes could also be a contributing factor. Anomalous lower seismic velocities in the shallow sequence (Feitz, Radke, et al., 2018;Figure 8) suggest an irregular interval of lower density and/or reduced induration (Figures 17a and 18). Accordingly, the degree of influence of late dissolution effects vs changing sedimentation rates remains unresolved. ...
A fully cored sequence of Hesse Clay, Port Campbell Limestone and uppermost Gellibrand Marl in the onshore Otway Basin, southeastern Australia, offers new insight into the evolution of the middle Miocene Port Campbell Limestone. The Port Campbell Limestone comprises grey unconsolidated to semi-consolidated and rarely lithified bioclastic muddy carbonate sands in a stack of thin repetitive cycles within cycles of predominantly shoaling-upward character. A glauconitic band with a distinctive mollusc–echinoderm–bryozoan fauna provides a distinctive marker interval in the sequence. In mineralogy, the Port Campbell Limestone is predominantly calcite with traces of remnant aragonite in muddier low-permeability sands, and with dolomitic zones in permeable intervals. The small non-carbonate component of the Port Campbell Limestone is between 3 and 15 wt% and comprises quartz silt with minor clay, feldspar and mica. Dissolution overprints are prominent throughout the carbonate sequence. Three distinct geochemical signatures of provenance are evident in the Port Campbell Limestone sequence, including possible volcanogenic contributions with felsic sources. Foraminifera are common and generally well preserved. Foraminiferal data suggest a depositional transition from outer shelf conditions in the Gellibrand Marl at ca 15 Ma to middle shelf environments in the lower part of the Port Campbell Limestone during the Middle Miocene Climatic Optimum (MMCO) at ca 14.24 Ma. Shallowing after 14 Ma indicates variable paleodepths of <70 m during and following the end of the Middle Miocene Climatic Transition (MMCT) at ca 13.2 Ma when the sequence was emergent for a brief but undetermined period, corresponding with sharp changes in geochemical ratios. Observed cyclicity in these mid-shelfal, cold-water carbonates is strongly correlated with orbital forcings—eccentricity and obliquity. Sedimentation rates determined from cyclostratigraphic analysis indicate 4–6 cm/kyr at the end of the MMCO, diminishing to 1.5–3 cm/kyr during the MMCT and the subsequent accumulation of the Port Campbell Limestone.
• KEY POINTS
• The Port Campbell Limestone is a stack of thin repetitive depositional cycles within cycles. The cyclicity is strongly correlated with orbital forcings—eccentricity and obliquity—and this is reflected in the geochemistry.
• Foraminiferal data suggest a depositional transition from outer shelf conditions in the Gellibrand Marl at ca 15 Ma to middle shelf environments in the lower part of the Port Campbell Limestone during the Middle Miocene Climatic Optimum (MMCO) at ca 14.24 Ma.
• The sequence was emergent for a brief but undetermined period at ca 13.2 Ma, corresponding with sharp changes in geochemical ratios.
• Three distinct geochemical signatures of provenance are evident in the Port Campbell Limestone sequence, including possible volcanogenic contributions with felsic sources.
... The ability to reuse existing infrastructure has occurred before in research projects and field trials such as with the Frio Brine I Project [19] and at the CO2CRC Otway Project Stage 1 (Naylor production well, [20]). Both project proponents acknowledge a range of issues relating to the reuse of infrastructure not discussed further here. ...
... In 2016, a shallow, predominantly strike-slip fault, named Brumbys Fault, was mapped at the Otway site [3] and an initial conceptual model of the site developed [4]. The model comprised an upper 3-5 m thick clay layer, a 121 m thick limestone aquifer (the Port Campbell Limestone, PCL), and a 355 m thick, impermeable and homogeneous marl (the Gellibrand Marl). ...
... Using geochemical correlation of the two wells, we were able to confirm that the Brumbys Fault extends to the base of the upper Hesse Clay, with ~2 m offset near the surface, consistent with the results from seismic data interpretation. This is smaller than the approximate 4.2 m offset observed at the base of the PCL [3,4]. Baseline soil gas and soil flux surveys showed no indication of pre-existing deep CO2 migration up the fault. ...
... A major unknown from our earlier work was whether the fault extended to the base of the Hesse Clay, as the fault was undetectable in the near surface (top ~0-40 m) due to low seismic data resolution in this zone [3]. Previous analysis of seismic data found that Brumbys Fault dies out at approximately 380 m depth and is not connected to the deeper geological storage formations located at the CO2CRC Otway site [4]. The fault is very steeply dipping near the surface and strikes approximately 165°N. ...
CO2CRC has made a significant investment into establishing the feasibility of conducting a CO2 injection experiment into a shallow fault. This world-leading experiment, located at the CO2CRC Otway International Test Centre in Victoria, Australia, would seek to improve our understanding of the conditions necessary for CO2 to move vertically up faults. The work undertaken during Phase 2 of the Otway Fault Project confirms the experiment is technically feasible and can be done safely. Two appraisal wells drilled and cored through the shallow Brumbys Fault indicate the fault extends to the base of the upper 2 m thick Hesse Clay layer, which forms the seal to the underlying Port Campbell Limestone aquifer. The fault does not have a defined core but an approximately 6-10 m wide fault cataclastic zone. Permeability within the Port Campbell Limestone is variable, ranging from tens to thousands of millidarcies. The rock strength is low, however, and it is recommended to conduct the experiment at approximately 80 m depth rather than the 40 m originally proposed. This provides more confining pressure and will ensure that the injection pressure does not exceed the fracture pressure. A deeper injection also provides better spatial and timing conditions for geophysical monitoring and tracking of the CO2 plume. Simulations indicate only a small 10 tonne CO2 injection experiment would be required to monitor CO2 migration using geophysical techniques. In addition to providing an opportunity to demonstrate semi-continuous, near real-time monitoring of CO2 migration up a fault, the planned CO2 injection experiment presents a unique opportunity to obtain field measurements on vertical fault permeability. It also provides an opportunity to predict fluid flow and potential metal remobilisation through comprehensive reactive transport modelling, collection and analysis of core post CO2 injection, and evaluate the effectiveness of the modelling versus field observations.
... Few of these projects put emphasis on detecting CO2 leakage on its migration path between the storage complex and groundwater resources or the atmosphere. Only a few recent projects in Canada [5] and eastern Australia [6], have been investigating the migration behaviour and detectability of gaseous CO2 between 25m to 600m depth. Furthermore, the identification and characterisation of potential leakage processes and pathways are important for developing properly targeted monitoring schemes [7,8]. ...
... Previous field tests have focussed on shallow-release experiments performed at less than 25 m depth (Roberts and Stalker, 2017;Roberts et al., 2018) or CO 2 storage experiments at more than 600 m depth (Michael et al., 2010 and references therein). However, except for a few recent projects in Canada (Macquet and Lawton, 2019) and eastern Australia (Feitz et al., 2018), experiments investigating the migration behaviour and detectability of gaseous CO 2 at intermediate depths https://doi.org/10.1016/j.ijggc.2020.103100 Received 10 December 2019; Received in revised form 15 June 2020; Accepted 15 June 2020 between 25 m and 600 m have been lacking. ...
A controlled-release test at the In-Situ Laboratory Project in Western Australia injected 38 tonnes of gaseous CO2 between 336−342 m depth in a fault zone, and the gas was monitored by a wide range of downhole and surface monitoring technologies. Injection of CO2 at this depth fills the gap between shallow release (<25 m) and storage (>600 m) field trials. The main objectives of the controlled-release test were to assess the monitorability of shallow CO2 accumulations, and to investigate the impacts of a fault zone on CO2 migration.
CO2 arrival was detected by distributed temperature sensing at the monitoring well (7 m away) after approximately 1.5 days and an injection volume of 5 tonnes. The CO2 plume was detected also by borehole seismic and electric resistivity imaging. The detection of significantly less than 38 tonnes of CO2 in the shallow subsurface demonstrates rapid and sensitive monitorability of potential leaks in the overburden of a commercial-scale storage project, prior to reaching shallow groundwater, soil zones or the atmosphere.
Observations suggest that the fault zone did not alter the CO2 migration along bedding at the scale and depth of the test. Contrary to model predictions, no vertical CO2 migration was detected beyond the perforated injection interval. CO2 and formation water escaped to the surface through the monitoring well at the end of the experiment due to unexpected damage to the well’s fibreglass casing. The well was successfully remediated without impact to the environment and the site is ready for future experiments.
... Based on the data collected to date, the shallow geology of the CO2CRC Otway study area can be described by three sequences [4]: ...
... Inferred variations in fault permeability on the modelled Brumby Fault surface, caused by alternating tight and dilational segments created with sinistral strike slip movement[4]. The planned fault intersection points for the proposed groundwater observation wells are shown (Well 1 = tight; Well 2 = dilated). ...
CO2CRC and its partners are undertaking a feasibility study for a planned CO2 controlled release and monitoring experiment on a shallow fault at the CO2CRC Otway Research Facility. In this project we plan to image, using a diverse range of geophysical and geochemical CO2 monitoring techniques, the migration of CO2 up a fault from a controlled release point at approximately 30 m depth. This paper describes the results of site characterisation and modelling work undertaken to date. It also includes a description of the activities planned that will enable for a more detailed characterization of the fault and proposed injection interval. Together these results will enable an assessment as to whether the planned injection experiment is feasible and how it can be optimally designed
... The layer above the aquifer is relatively thin but clay rich and impermeable. The newly-identified shallow Brumbys Fault disrupts the limestone with a predominant strike-slip component and small vertical offset of about 4.5 m [3]. ...
... The model considers an uppermost relatively thin but clay-rich layer and a stratified Miocene Port Campbell Limestone with wide ranging permeability depending on the depositional facies. A full description of the static model can be found in Feitz et al. [3]. Briefly, the 3D static model used for dynamic simulation was the upper part of 3D grid model constructed by static modelling, which included 17 vertical layers from the surface to the bottom of PCL Zone 16 and 577,830 grid cells, and the burial depth was from 46.47 m (above MSL) to -9.53 m (below MSL) [3]. ...
... A full description of the static model can be found in Feitz et al. [3]. Briefly, the 3D static model used for dynamic simulation was the upper part of 3D grid model constructed by static modelling, which included 17 vertical layers from the surface to the bottom of PCL Zone 16 and 577,830 grid cells, and the burial depth was from 46.47 m (above MSL) to -9.53 m (below MSL) [3]. Fig. 2 shows the 3D geological model used for dynamic modelling in this study. ...
A dynamic modelling study was undertaken to assess the feasibility of a planned CO2 injection experiment into a shallow fault at the CO2CRC's Otway Research Facility. The aim was to identify key physical properties that strongly influence migration behaviour but are presently unmeasured. Two different simulators (CMG-GEM and TOUGH2) were used to model this experiment. Both simulation efforts indicate that the proposed experiment is feasible, but show the need for better data on the maximum injection pressure and the permeability distribution in the near-surface region (including the continuity of the clay layer). During the simulation with high injection rate, there could be a rapid accumulation of CO2 at the early injection stage due to the constraints of maximum injection pressure. The modelling results suggest that the dominant trapping mechanisms are likely to be free CO2 gas trapped by the upper clay layer and residual trapping. The total amount of CO2 that could be injected increased with greater injection pressure, injection rate and maximum residual gas saturation. The results suggest that dissolution of CO2 is likely to continue to increase during the injection and post-injection stages. After the CO2 injection phase, the gas was found to spread laterally within the reservoir and moved upward along the permeable grid cells at the modelled fault. A comparison between the modelling approaches suggests that if there is a desire to have CO2 migrate up the fault and reach the upper clay layer, it will be important to conduct the injection experiment at the most permeable sections of the fault and inject CO2 into a shallow high permeability layer. It is necessary to clarify whether there is an unsaturated zone beneath the clay layer as this is speculated to exist but is unknown.
CO2CRC has made a significant investment into establishing the feasibility of conducting a CO2 injection experiment into a shallow fault at the CO2CRC Otway International Test Centre. Two appraisal wells drilled and cored through Brumbys Fault indicate the fault extends to the base of the upper 2 m thick Hesse Clay layer, which forms a seal to the underlying Port Campbell Limestone aquifer. The fault does not have a defined core; rather, it is expressed by an approximately 6-10 m wide cataclastic zone. Permeability within the Port Campbell Limestone is variable, ranging from tens to thousands of millidarcies (10 − 14 to 10 − 12 m 2). The rock strength is low and it is recommended to conduct the experiment at approximately 80 m depth rather than the 40 m originally proposed. This provides more confining pressure and will ensure that the injection pressure does not exceed the fracture pressure. A deeper injection also provides better spatial and timing conditions for geophysical monitoring and tracking of the CO2 plume. Simulations indicate that a 10 t CO2 injection experiment would be sufficient to monitor CO2 migration using geophysical techniques and the planned deployment of reverse 4D vertical seismic profiling would be able to track this small quantity of CO2 up a fault. In addition to providing an opportunity to demonstrate semi-continuous, near real-time monitoring of CO2 migration up a fault, the planned CO2 injection experiment presents a unique opportunity to obtain field measurements on vertical fault permeability at a shallow strike-slip fault.
