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Title: Impact of Micro-to Meso-scale Fractures on Sealing Behavior of Argillaceous Cap Rocks For CO 2 Sequestration

Abstract

This multi-disciplinary project evaluated seal lithologies for the safety and security of long-term geosequestration of CO 2. We used integrated studies to provide qualitative risk for potential seal failure; we integrated data sets from outcrop, core, geochemical analysis, rock failure properties from mechanical testing, geophysical wireline log analysis, and geomechanical modeling to understand the effects of lithologic heterogeneity and changing mechanical properties have on the mechanical properties of the seal. The objectives of this study were to characterize cap rock seals using natural field analogs, available drillhole logging data and whole-rock core, geochemical and isotopic analyses. Rock deformation experiments were carried out on collected samples to develop better models of risk estimation for potential cap rock seal failure. We also sampled variably faulted and fractured cap rocks to examine the impacts of mineralization and/or alteration on the mechanical properties. We compared CO 2 reacted systems to non-CO 2 reacted seal rock types to determine response of each to increased pore fluid pressures and potential for the creation of unintentional hydrofractures at depth.

Authors:
ORCiD logo [1]
  1. Utah State Univ., Logan, UT (United States)
Publication Date:
Research Org.:
Utah State Univ., Logan, UT (United States)
Sponsoring Org.:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
OSTI Identifier:
1302338
Report Number(s):
USU-DOE-0004991-1
DOE Contract Number:
SC0004991
Resource Type:
Technical Report
Country of Publication:
United States
Language:
English
Subject:
58 GEOSCIENCES; CO2; seal; integrity; bypass; storage

Citation Formats

Evans, James. Impact of Micro-to Meso-scale Fractures on Sealing Behavior of Argillaceous Cap Rocks For CO2 Sequestration. United States: N. p., 2016. Web. doi:10.2172/1302338.
Evans, James. Impact of Micro-to Meso-scale Fractures on Sealing Behavior of Argillaceous Cap Rocks For CO2 Sequestration. United States. doi:10.2172/1302338.
Evans, James. Mon . "Impact of Micro-to Meso-scale Fractures on Sealing Behavior of Argillaceous Cap Rocks For CO2 Sequestration". United States. doi:10.2172/1302338. https://www.osti.gov/servlets/purl/1302338.
@article{osti_1302338,
title = {Impact of Micro-to Meso-scale Fractures on Sealing Behavior of Argillaceous Cap Rocks For CO2 Sequestration},
author = {Evans, James},
abstractNote = {This multi-disciplinary project evaluated seal lithologies for the safety and security of long-term geosequestration of CO2. We used integrated studies to provide qualitative risk for potential seal failure; we integrated data sets from outcrop, core, geochemical analysis, rock failure properties from mechanical testing, geophysical wireline log analysis, and geomechanical modeling to understand the effects of lithologic heterogeneity and changing mechanical properties have on the mechanical properties of the seal. The objectives of this study were to characterize cap rock seals using natural field analogs, available drillhole logging data and whole-rock core, geochemical and isotopic analyses. Rock deformation experiments were carried out on collected samples to develop better models of risk estimation for potential cap rock seal failure. We also sampled variably faulted and fractured cap rocks to examine the impacts of mineralization and/or alteration on the mechanical properties. We compared CO2 reacted systems to non-CO2 reacted seal rock types to determine response of each to increased pore fluid pressures and potential for the creation of unintentional hydrofractures at depth.},
doi = {10.2172/1302338},
journal = {},
number = ,
volume = ,
place = {United States},
year = {Mon Aug 01 00:00:00 EDT 2016},
month = {Mon Aug 01 00:00:00 EDT 2016}
}

Technical Report:

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  • The objectives of this project are to understand the processes that occur when a maximum of 70,000 metric tonnes of CO2 are injected into two different formations to evaluate the response in different lithofacies and depositional environments. The evaluation will be accomplished through the use of both in situ and indirect MVA (monitoring, verification, and accounting) technologies. The project will optimize for carbon storage accounting for 99% of the CO2 using lab and field testing and comprehensive characterization and modeling techniques. Site characterization and CO2 injection should demonstrate state-of-the-art MVA tools and techniques to monitor and visualize the injected CO2more » plume and to refine geomodels developed using nearly continuous core, exhaustive wireline logs, and well tests and a multi-component 3-D seismic survey. Reservoir simulation studies will map the injected CO2 plume and estimate tonnage of CO2 stored in solution, as residual gas, and by mineralization and integrate MVA results and reservoir models shall be used to evaluate CO2 leakage. A rapid-response mitigation plan was developed to minimize CO2 leakage and provide a comprehensive risk management strategy. The CO2 was intended to be supplied from a reliable facility and have an adequate delivery and quality of CO2. However, several unforeseen circumstances complicated this plan: (1) the initially negotiated CO2 supply facility went offline and contracts associated with CO2 supply had to be renegotiated, (2) a UIC Class VI permit proved to be difficult to obtain due to the experimental nature of the project. Both subjects are detailed in separate deliverables attached to this report. The CO2 enhanced oil recovery (EOR) and geologic storage in Mississippian carbonate reservoir was sucessully deployed. Approximately 20,000 metric tons of CO2 was injected in the upper part of the Mississippian reservoir to verify CO2 EOR viability in carbonate reservoirs and evaluate a potential of transitioning to geologic CO2 storage through EOR. A total of 1,101 truckloads, 19,803 metric tons—an average of 120 tonnes per day—were delivered over the course of injection that lasted from January 9 to June 21, 2016. After cessation of CO2 injection, the KGS 2-32 well was converted to water injector and continues to operate. CO2 EOR progression in the field was monitored weekly with fluid level, temperature, and production recording and formation fluid composition sampling. It is important to note that normally, CO2 EOR pilots are less efficient than commercial operations due to lack of directional and precise well control, lack of surface facilities for CO2 recycling, and other factors. As a result of this pilot CO2 injection, the observed incremental average oil production increase was ~68% with only ~18% of injected CO2 produced back. Decline curve analysis forecasts of additional cumulative oil produced were 32.44M STB to the end of 2027. Wellington Mississippian pilot efficiency by the end of forecast calculations is 11 MCF per barrel of produced oil. Using 32M STB oil production and $1,964,063 cost of CO2, CO2 EOR cost per barrel of oil production is ~$60. Simple but robust monitoring technologies proved to be very efficient in detecting and locating CO2. High CO2 reservoir retentions with low yields within an actively producing field could help to estimate real-world risks of CO2 geological storage for future projects. The Wellington Field CO2 EOR was executed in a controlled environment with high efficiency. This case study proves that CO2 EOR could be successfully applied in Kansas carbonate reservoirs if CO2 sources and associated infrastructure are available. Recent developments in unconventional resources development in Mid-Continent USA and associated large volume disposal of backflow water and the resulting seismic activity have brought more focus and attention to the Arbuckle Group in southern Kansas. Despite the commercial interest, limited essential information about reservoir properties and structural elements has impeded the management and regulation of disposal, an issue brought to the forefront by recent seismicity in and near areas of large volumes and rates of brine disposal. The Kansas Geological Survey (KGS) collected, compiled, and analyzed available data, including well logs, core data, step rate tests, drill stem tests, 2-D and 3-D seismic data, water level measurements, and others types of data. Several exploratory wells were drilled and core was collected and modern suites of logs were analyzed. Reservoir properties were populated into several site-specific geological models. The geological models illustrate the highly heterogeneous nature of the Arbuckle Group. Vertical and horizontal variability results in several distinct hydro-stratigraphic units that are the result of both depositional and diagenetic processes. During the course of this project, it has been demonstrated that advanced seismic interpretation methods can be used successfully for characterization of the Mississippian reservoir and Arbuckle saline aquifer. Analysis of post-stack 3-D seismic data at the Mississippian reservoir showed the response of a gradational velocity transition. Pre-stack gather analysis showed that porosity zones of the Mississippian and Arbuckle reservoirs exhibit characteristic amplitude versus offset (AVO) response. Simultaneous AVO inversion estimated P- and S-impedances. The 3-D survey gather azimuthal anisotropy analysis (AVAZ) provided information about the fault and fracture network and showed good agreement to the regional stress field and well data. Mississippian reservoir porosity and fracture predictions agreed well with the observed mobility of injected CO2 in KGS well 2-32. Fluid substitution modeling predicted acoustic impedance reduction in the Mississippian carbonate reservoir introduced by the presence of CO2. Seismicity in the United States midcontinent has increased by orders of magnitude over the past decade. Spatiotemporal correlations of seismicity to wastewater injection operations have suggested that injection-related pore fluid pressure increases are inducing the earthquakes. In this investigation, we examine earthquake occurrence in southern Kansas and northern Oklahoma and its relation to the change in pore pressure. The main source of data comes from the Wellington Array in the Wellington oil field, in Sumner County, Kansas, which has monitored for earthquakes in central Sumner County, Kansas, since early 2015. The seismometer array was established to monitor CO2 injection operations at Wellington Field. Although no seismicity was detected in association with the spring 2016 Mississippian CO2 injection, the array has recorded more than 2,500 earthquakes in the region and is providing valuable understanding to induced seismicity. A catalog of earthquakes was built from this data and was analyzed for spatial and temporal changes, stress information, and anisotropy information. The region of seismic concern has been shown to be expanding through use of the Wellington earthquake catalog, which has revealed a northward progression of earthquake activity reaching the metropolitan area of Wichita. The stress orientation was also calculated from this earthquake catalog through focal mechanism inversion. The calculated stress orientation was confirmed through comparison to other stress measurements from well data and previous earthquake studies in the region. With this knowledge of the stress orientation, the anisotropy in the basement could be understood. This allowed for the anisotropy measurements to be correlated to pore pressure increases. The increase in pore pressure was monitored through time-lapse shear-wave anisotropy analysis. Since the onset of the observation period in 2010, the orientation of the fast shear wave has rotated 90°, indicating a change associated with critical pore pressure build up. The time delay between fast and slow shear wave arrivals has increased, indicating a corresponding increase in anisotropy induced by pore pressure rise. In-situ near-basement fluid pressure measurements corroborate the continuous pore pressure increase revealed by the shear-wave anisotropy analysis over the earthquake monitoring period. This research is the first to identify a change in pore fluid pressure in the basement using seismological data and it was recently published in the AAAS journal Science Advances (Nolte et al., 2017). The shear-wave splitting analysis is a novel application of the technique, which can be used in other regions to identify an increase in pore pressure. This increasing pore fluid pressure has become more regionally extensive as earthquakes are occurring in southern Kansas, where they previously were absent. These monitoring techniques and analyses provide new insight into mitigating induced seismicity’s impact on society.« less
  • The overall objective of this proposal was to develop tools for better understanding, modeling and risk assessment of CO 2 permanence in geologic formations at the geologic basin scale.
  • The purpose of this report is to provide a summary of individual local-­scale CCS site characterization studies conducted in Colorado, New Mexico and Utah. These site-­ specific characterization analyses were performed as part of the “Characterization of Most Promising Sequestration Formations in the Rocky Mountain Region” (RMCCS) project. The primary objective of these local-­scale analyses is to provide a basis for regional-­scale characterization efforts within each state. Specifically, limits on time and funding will typically inhibit CCS projects from conducting high-­ resolution characterization of a state-­sized region, but smaller (< 10,000 km{sup 2}) site analyses are usually possible, and suchmore » can provide insight regarding limiting factors for the regional-­scale geology. For the RMCCS project, the outcomes of these local-­scale studies provide a starting point for future local-­scale site characterization efforts in the Rocky Mountain region.« less
  • 1. Drilled, cored, and logged three wells to the basement and collecting more than 2,700 ft of conventional core; obtained 20 m i2 of multicomponent 3D seismic imaging and merged and reprocessed more than 125 mi 2 of existing 3D seismic data for use in modeling CO 2- EOR oil recovery and CO 2 storage in five oil fields in southern Kansas. 2. Determined the technical feasibility of injecting and sequestering CO 2 in a set of four depleted oil reservoirs in the Cutter, Pleasant Prairie South, Eubank, and Shuck fields in southwest Kansas; of concurrently recovering oil from thosemore » fields; and of quantifying the volumes of CO2 sequestered and oil recovered during the process. 3. Formed a consortium of six oil operating companies, five of which own and operate the four fields. The consortium became part of the Southwest Kansas CO 2-EOR Initiative for the purpose of sharing data, knowledge, and interest in understanding the potential for CO 2-EOR in Kansas. 4. Built a regional well database covering 30,000 mi 2 and containing stratigraphic tops from ~90,000 wells; correlated 30 major stratigraphic horizons; digitized key wells, including wireline logs and sample logs; and analyzed more than 3,000 drill stem tests to establish that fluid levels in deep aquifers below the Permian evaporites are not connected to the surface and therefore pressures are not hydrostatic. Connectivity with the surface aquifers is lacking because shale aquitards and impermeable evaporite layers consist of both halite and anhydrite. 5. Developed extensive web applications and an interactive mapping system that do the following: a. Facilitate access to a wide array of data obtained in the study, including core descriptions and analyses, sample logs, digital (LAS) well logs, seismic data, gravity and magnetics maps, structural and stratigraphic maps, inferred fault traces, earthquakes, Class I and II disposal wells, and surface lineaments. b. Provide real-time analysis of the project dataset, including automated integration and viewing of well logs, core, core analyses, brine chemistry, and stratigraphy using the Java Profile app. A cross-section app allows for the display of log data for up to four wells at a time. 6. Integrated interpretations from the project’s interactive web-based mapping system to gain insights to aid in assessing the efficacy of geologic CO 2 storage in Kansas and insights toward understanding recent seismicity to aid in evaluating induced vs. naturally occurring earthquakes. 7. Developed a digital type-log system, including web-based software to modify and refine stratigraphic nomenclature to provide stakeholders a common means for communication about the subsurface. 8. Contracted use of a nuclear magnetic resonance (NMR) log and ran it slowly to capture response and characterize larger pores common for carbonate reservoirs. Used NMR to extend core analyses to apply permeability, relative permeability to CO 2, and capillary pressure to the major rock types, each uniquely expressed as a reservoir quality index (RQI), present in the Mississippian and Arbuckle rocks. 9. Characterized and evaluated the possible role of microbes in dense brines. Used microbes to compliment H/O stable isotopes to fingerprint brine systems. Used perforation/swabbing to obtain samples from multiple hydrostratigraphic units and confirmed equivalent results using less expensive drill stem tests (DST). 10. Used an integrated approach from whole core, logs, tests, and seismic to verify and quantify properties of vuggy, brecciated, and fractured carbonate intervals. 11. Used complex geocellular static and dynamic models to evaluate regional storage capacity using large parallel processing. 12. Carbonates are complex reservoirs and CO 2-EOR needs to move to the next generation to increase effectiveness of CO 2 and efficiency and safety of the injection.« less