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At least 307 records · Page 17

Proposed Drill Sites

Proposed drill sites for intermediate depth temperature gradient holes and/or deep resource confirmation wells. Temperature gradient contours based on shallow TG program and faults interpreted from seismic reflection survey are shown, as are two faults interpreted by seismic contractor Optim but not by Oski Energy, LLC.

15 GEOTHERMAL ENERGY↗

Synthesizing 3D Surfaces from Parameterized Strip Charts

We believe 3D information visualization has the power to unlock new levels of productivity in the monitoring and control of complex processes. Our goal is to provide visual methods to allow for rapid human insight into systems consisting of thousands to millions of parameters. We explore this hypothesis in two complex domains: NASA program management and NASA International Space Station (ISS) spacecraft computer operations. We seek to extend a common form of visualization called the strip chart from 2D to 3D. A strip chart can display the time series progression of a parameter and allows for trends and events to be identified. Strip charts can be overlayed when multiple parameters need to visualized in order to correlate their events. When many parameters are involved, the direct overlaying of strip charts can become confusing and may not fully utilize the graphing area to convey the relationships between the parameters. We provide a solution to this problem by generating 3D surfaces from parameterized strip charts. The 3D surface utilizes significantly more screen area to illustrate the differences in the parameters and the overlayed strip charts, and it can rapidly be scanned by humans to gain insight. The selection of the third dimension must be a parallel or parameterized homogenous resource in the target domain, defined using a finite, ordered, enumerated type, and not a heterogeneous type. We demonstrate our concepts with examples from the NASA program management domain (assessing the state of many plans) and the computers of the ISS (assessing the state of many computers). We identify 2D strip charts in each domain and show how to construct the corresponding 3D surfaces. The user can navigate the surface, zooming in on regions of interest, setting a mark and drilling down to source documents from which the data points have been derived. We close by discussing design issues, related work, and implementation challenges.

Robinson, Peter I.↗

Mineralogy of Vera Rubin Ridge from the Mars Science Laboratory CheMin Instrument

Vera Rubin ridge (VRR) is an erosion-resistant feature on the northwestern slope of Mount Sharp in Gale crater, Mars, and orbital visible/short-wave infrared measurements indicate it contains red-colored hematite. The Mars Science Laboratory Curiosity rover performed an extensive campaign on VRR to study its mineralogy, geochemistry, and sedimentology to determine the depositional and diagenetic history of the ridge and constrain the processes by which the hematite could have formed. X-ray diffraction (XRD) data from the CheMin instrument of four samples drilled on and below VRR demonstrate differences in iron, phyllosilicate, and sulfate mineralogy and hematite grain size. Hematite is common across the ridge, and its detection in a gray-colored outcrop suggested localized regions with coarse-grained hematite, which commonly forms from warm fluids. Broad XRD peaks for hematite in one sample below VRR and the abundance of FeOT in the amorphous component suggest the presence of nano-crystalline hematite and amorphous Fe oxides/oxyhydroxides. Well-crystalline akaganeite and jarosite are present in two samples drilled from VRR, indicating at least limited alteration by acid-saline fluids. Collapsed nontronite is present below VRR, but samples from VRR contain phyllosilicate with d(001) = 9.6 Å, possibly from ferripyrophyllite or an acid-altered smectite. The most likely cementing agents creating the ridge are hematite and opaline silica. We hypothesize late diagenesis can explain much of the mineralogical variation on the ridge, where multiple fluid episodes with variable pH, salinity, and temperature altered the rocks, causing the precipitation and crystallization of phases that are not otherwise in equilibrium.

E. B. Rampe↗

Microbial Diversity in the Deep Sandstones of a Carbon Sequestration Well

A lack of data on microbes in the deep subsurface hinders our ability to predict how these microbial communities will respond to carbon sequestration. Previous studies predicted how microbial communities may shift due to an influx of carbon dioxide (CO2) by 1) examining waters with naturally-occurring elevated CO2 concentration; and/or 2) via experiments involving exposure of laboratory microbial strains to elevated concentrations of CO2 relative to their native subsurface environment. To identify microbes naturally found in carbon sequestration target reservoirs, water samples were collected from three potential target reservoirs in the Powder River Basin, Wyoming which include the Hulett, Lakota, and Minnelusa sandstones. Water samples were collected at depths of 8,060 ft (Lakota), 8,330 ft (Hulett), 9,380 ft (Minnelusa), 9,463 ft (Minnelusa), and 9,544 ft (Minnelusa) for microbial DNA analysis as well as water chemistry and stable isotope analyses to look for any microbial trends that could be related to water chemistry alone. Identification of microbial communities present in the sampled water was determined via 16S rRNA sequencing; these data were compared to 16S rRNA isolated from drilling mud to distinguish native from any microbes introduced via drilling processes. Enrichment experiments reveal that the collected water samples contain active (e.g., growing) microbes and how the microbial community may adapt upon the introduction of CO2.

Wawrousek, K↗

Pahute Mesa Well Development and Testing Analyses for Wells ER-20-7, ER-20-8 #2, and ER-EC-11, Revision 1

This report analyzes the following data collected from ER-20-7, ER-20-8 No.2, and ER-EC-11 during WDT operations: (1) Chemical indicators of well development (Section 2.0); (2) Static hydraulic head (Section 3.0); (3) Radiochemistry and geochemistry (Section 4.0); (4) Drawdown observed at locations distal to the pumping well (Section 5.0); and (5) Drilling water production, flow logs, and temperature logs (Section 6.0). The new data are further considered with respect to existing data as to how they enhance or change interpretations of groundwater flow and transport, and an interim small-scale conceptual model is also developed and compared to Phase I concepts. The purpose of well development is to remove drilling fluids and drilling-associated fines from the formation adjacent to a well so samples reflecting ambient groundwater water quality can be collected, and to restore hydraulic properties near the well bore. Drilling fluids can contaminate environmental samples from the well, resulting in nonrepresentative measurements. Both drilling fluids and preexisting fines in the formation adjacent to the well can impede the flow of water from the formation to the well, creating artifacts in hydraulic response data measured in the well.

54 ENVIRONMENTAL SCIENCES↗

Southwest Regional Partnership on Carbon Sequestration: Phase III (Final Scientific/Technical Report)

The Southwest Regional Partnership on Carbon Sequestration (SWP) is one of 7 regional partnerships formed in 2003 under the U.S. Department of Energy’s (DOE) Regional Carbon Sequestration Partnerships (RCSPs) initiative. The overall purpose of the initiative was to help determine and implement the technology, infrastructure, and regulations most appropriate to promote carbon storage in different regions of the country. Covering Arizona, Colorado, New Mexico, Oklahoma, Utah, and parts of Texas, Wyoming, and Kansas, the SWP evaluated regional carbon storage and utilization potential and focused on technologies and sites that could complement the region’s strong position in energy production. The project progressed through three phases: • Phase I (2003–2005): Characterized regional geologic formations and CO 2 sources, assessed sequestration potential, and identified pilot test sites. • Phase II (2005–2013): Conducted small-scale field tests to validate sequestration methods, including geologic and terrestrial projects. • Phase III (2008–2022): Demonstrated large-scale CO 2 injection at a commercial oil field to test monitoring, verification, and long-term storage strategies. This report covers Phase III. The final project site, the Farnsworth Unit (FWU) in Texas, provided real-world testing of reservoir characterization, monitoring, and risk evaluation tools and processes that could be used in any commercial scale carbon capture, utilization, and storage (CCUS) project. Extensive data collection and analysis helped refine best practices for reservoir characterization, injection monitoring, and storage verification. The SWP contributed to national databases, DOE best practice manuals, and regional geological assessments to support future sequestration efforts. Key lessons learned include the importance of robust data management, strategic site selection, regulatory navigation, and effective industry collaboration. The project’s findings will inform ongoing and future carbon storage initiatives. Task 1 (Regional Characterization) • The SWP continued to participate in national outreach efforts and NATCARB. • The SWP evaluated multiple potential sites before selecting the FWU as the primary field test location. Task 2 (Public Outreach and Education) • The SWP contributed to national databases, DOE best practice manuals, and regional geological assessments to support future sequestration efforts. Task 3 (Permitting and Regulatory Compliance) • The SWP ensured compliance with federal and state regulations, including National Environmental Policy Act (NEPA) requirements. • The SWP obtained all necessary permits for drilling, injection, and monitoring activities. Task 4 (Site Characterization and Planning) • The SWP developed work plans for four key activities: characterization, simulation, monitoring and verification, and risk evaluation. • The SWP collected and synthesized legacy data from multiple sources to build initial static geological models and dynamic reservoir models demonstrating project feasibility. • The SWP conducted an initial risk evaluation and developed mitigation plans. Task 5 (Field Operations and Data Collection) • The SWP drilled, logged, and cored three characterization wells to gather critical subsurface data. • The SWP conducted multiple geophysical surveys, including 3D seismic, crosswell seismic, and vertical seismic profiling, to improve reservoir characterization. Task 6 (Monitoring and Verification) • The SWP performed extensive geological characterization using data from characterization wells and seismic surveys. • The SWP established a surface monitoring network to track CO 2 flux in soil gas, groundwater chemistry, and near-surface atmospheric CO 2 levels. • The SWP built and refined reservoir models to study the effects of relative permeability on simulation behavior and improve calibration with experimental data. Task 7 (Risk Assessment and Model Refinement) • The SWP conducted multiple studies to evaluate reservoir integrity, predict CO 2 plume behavior and improve predictive modeling capabilities. • The SWP refined geological models and used them to enhance the accuracy of simulation models. • The SWP continued quantitative risk assessment of top-ranked risks and strengthened the link between qualitative and quantitative risk methodologies.

02 PETROLEUM↗

Wabash CarbonSAFE Subtask 7.1 – Pre-drilling Site Assessment Topical Report: DOE-FE0031626-1

The Wabash CarbonSAFE project will drill a stratigraphic test well at the Wabash Valley Resources facility near Terre Haute, Indiana. Lithologic, geomechanical, and geophysical data collected from samples testing and an extensive geophysical logging suite will be used to determine the feasibility for the geologic sequestration of 50 million metric tons or more of injected carbon dioxide. The primary target reservoir and caprock to be investigated for the Wabash CarbonSAFE project are the Mt. Simon Sandstone and Eau Claire Shale, respectively. The project team has assessed the planned Wabash #1 drilling site using subsurface geologic data and analyses from both Illinois and Indiana. These data were used to generate geologic structure and isopach thickness maps for target reservoir and caprock layers which were incorporated into a detailed discussion of the nature of the Illinois Basin’s Cambro-Ordovician carbon dioxide storage complex at the drilling site. Formation tops were prognosed for 19 lithologic units to aid drilling and coring procedures. Additional GIS analysis indicates that no known structural features will negatively impact the target storage reservoir or caprock, nor will protected and sensitive areas, groundwater resources, or existing resource development be negatively affected by Wabash #1 drilling activities. The Wabash #1 Geologic/Structure Test well drilling permit was awarded by Indiana Department of Natural Resources (IN-DNR) – Division of Oil and Gas on November 12th, 2019, and the well is expected to be drilled to a total depth of approximately 8,350 feet. Potential impacts on drilling progress include abandoned underground coal mines which mined the Springfield and Survant coals until 1964 and 1954, respectively, and a lost circulation zone in the Potosi Dolomite, which has been demonstrated to have intermittent cavernous porosity from karstification. This document also details the coring and sampling program, proposed logging suite, and well testing program, all of which will be dynamically reviewed as drilling progresses.

29 ENERGY PLANNING, POLICY, AND ECONOMY↗

Utah FORGE: Phase 3 Microgravity Data

A 4D microgravity survey began in early 2019 in order to benchmark surface and subsurface elevations prior to Phase 3 drilling and stimulation campaigns. Microgravity stations are collocated with GPS deformation benchmarks and use the same location survey data. Surveys are undertaken on a quarterly basis. The focus of current activities is comparative analysis of GPS survey results and InSAR analysis (see GDR Submission 1251) to check seasonal variance and to evaluate possible changes in the groundwater elevation. The attached zip file contains a text file and an Excel spreadsheet containing Utah FORGE Phase 3 processed "final" microgravity data through time. The data are identical in both files. The spreadsheet is only supplied for convenience. There is also a ReadMe.txt file that describes the field headings.

15 GEOTHERMAL ENERGY↗

An Analysis of the Published Mineral Resource Estimates of the Haji-Gak Iron Deposit, Afghanistan

The Haji-Gak iron deposit of eastern Bamyan Province, eastern Afghanistan, was studied extensively and resource calculations were made in the 1960s by Afghan and Russian geologists. Recalculation of the resource estimates verifies the original estimates for categories A (in-place resources known in detail), B (in-place resources known in moderate detail), and C{sub 1} (in-place resources estimated on sparse data), totaling 110.8 Mt, or about 6% of the resources as being supportable for the methods used in the 1960s. C{sub 2} (based on a loose exploration grid with little data) resources are based on one ore grade from one drill hole, and P{sub 2} (prognosis) resources are based on field observations, field measurements, and an ore grade derived from averaging grades from three better sampled ore bodies. C{sub 2} and P{sub 2} resources are 1,659.1 Mt or about 94% of the total resources in the deposit. The vast P{sub 2} resources have not been drilled or sampled to confirm their extent or quality. The purpose of this article is to independently evaluate the resources of the Haji-Gak iron deposit by using the available geologic and mineral resource information including geologic maps and cross sections, sampling data, and the analog-estimating techniques of the 1960s to determine the size and tenor of the deposit.

58 GEOSCIENCES↗

Completion Report for Well ER-20-11, Corrective Action Units 101 and 102: Central and Western Pahute Mesa

Well ER-20-11 was drilled for the U.S. Department of Energy, National Nuclear Security Administration Nevada Site Office in support of the Nevada Environmental Management Operations Underground Test Area (UGTA) Activity at the Nevada National Security Site (formerly Nevada Test Site), Nye County, Nevada. The well was drilled in September 2012 as part of the Central and Western Pahute Mesa Corrective Action Unit Phase II drilling program. Well ER-20-11 was constructed to further investigate the nature and extent of radionuclide-contaminated groundwater encountered in two nearby UGTA wells, to help define hydraulic and transport parameters for the contaminated Benham aquifer, and to provide data for the UGTA hydrostratigraphic framework model. The 44.5-centimeter (cm) surface hole was drilled to a depth of 520.0 meters (m) and cased with 34.0-cm casing to 511.5 m. The hole diameter was then decreased to 31.1 cm, and the borehole was drilled to a total depth of 915.6 m. The hole was completed to allow access for hydrologic testing and sampling in the target aquifer, which is a lava-flow aquifer known as the Benham aquifer. The completion casing string, set to the depth of 904.3 m, consists of a string of 6 5/8-inch (in.) stainless-steel casing hanging from a string of 7 5/8-in. carbon-steel casing. The stainless-steel casing has one slotted interval at 796.3 to 903.6 m. One piezometer string was installed, which consists of 2 7/8-in. stainless-steel tubing that hangs from 2 3/8-in. carbon-steel tubing via a crossover sub. This string was landed at 903.8 m and is slotted in the interval 795.3 to 903.1 m. Data collected during and shortly after hole construction include composite drill cuttings samples collected every 3.0 m, various geophysical logs, fluid samples (for groundwater chemistry analysis and tritium measurements), and water-level measurements. The well penetrated 915.6 m of Tertiary volcanic rock, including one saturated lava flow aquifer. Measurements on samples taken from the undeveloped well indicated elevated tritium levels within the Benham aquifer. The maximum tritium level measured with field equipment was 146,131 picocuries per liter from a sample obtained at the depth of 912.0 m. The fluid level was measured in the piezometer string at a depth of 504.5 m on September 26, 2012. All Fluid Management Plan (FMP) requirements for Well ER-20-11 were met. Analysis of monitoring samples and FMP confirmatory samples indicated that fluids generated during drilling at Well ER-20-11 met the FMP criteria for discharge to an unlined sump or designated infiltration area. Well development, hydrologic testing, and sampling will be conducted at a later date.

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗

Mineralogical Evidence for Environmental Change in the Clay-Sulfate Transition at Gale Crater, Mars

A primary reason for selecting Gale crater as the Mars Science Laboratory (MSL) Curiosity rover landing site was a clear mineralogical transition from Fe/Mg smectite in older strata to hydrated Mg sulfate salts in younger strata observed in orbital visible/shortwave-infrared reflectance data. This transition has been observed in other early-Hesperian terrains on Mars and has been hypothesized to signal a planet-wide change in climate from relatively warm and wet to cold and dry. Curiosity studied the sedimentology and geochemical and mineralogical composition of rocks in this “clay-sulfate transition” region from sols 3052 to 3572 (i.e., March 2021 to August 2022), with arrival at the sulfate unit on sol 3574. Here, we report on the mineralogical measurements made by the CheMin X-ray diffractometer of the six drill targets in the clay-sulfate transition and the first drill target in the sulfate unit. We use compositional data and sedimentological observations to interpret depositional and diagenetic environments and present hypotheses to explain the transition from clay minerals to hydrated Mg sulfates.

E. B. Rampe↗

Casing Annulus Monitoring of CO 2 Injection Using Wireless Autonomous Distributed Sensor Networks

Effective and secure carbon subsurface storage, involving the deep underground injection of CO 2 into geological formations where it is permanently trapped, is paramount to mitigating CO 2 emissions (Figure I). Ensuring the integrity of these storage sites and detecting potential leakage through the casing annulus necessitates robust monitoring. This work provides the first integrated demonstration of a wireless casing-annulus monitoring architecture that can operate in highly attenuating cement-brine environments relevant to CO 2 storage. This project focused on developing and validating a novel sensor system for integration with autonomous monitoring near the cement reservoir interface. The goal was a fully integrated Technology Readiness Level (TRL) 4/5 field validation of a distributed wireless intelligent sensor system providing real-time, direct subsurface formation measurements to enhance fluid movement monitoring in the cemented casing annulus. Achieving this objective required the development and integration of 1) wireless autonomous microsensor technology by California Institute of Technology (Caltech); 2) sensor packaging and emplacement technology by Research Triangle Institute (RTI); and 3) smart well completions using wireless active casing collars and NOV pipe by the Sandia National Lab (SNL). The collaboration with the Caltech team in this project aimed to develop millimeter-scale radio frequency identification (RFID) sensors capable of detecting CO 2 , pH, and/or methane levels. These sensors are engineered to be impervious to fluids, allowing them to be mixed with cement and installed within the casing annulus. They operate using RFID protocols at frequencies of 902–928 MHz for both power and communication. A Sandia National Laboratories’ team engaged their expertise in the development of a Smart Collar system designed for the wireless data collection from these RFID sensors embedded in the cement annulus and transmission of this information to the ground surface via IntelliPipe/IntelliServ NOV drill pipe. This is accomplished through inductive coupling at the collar, which facilitates data transfer through each segment of the pipe. Because the system cannot transmit a direct current signal to power the Smart Collar, both power and communication were implemented using alternating current and electromagnetic signals at varying frequencies. Furthermore, the developed microsensor technology had to be demonstrated and validated in comparison with reference transducer measurements in a field test site at The University of Texas at Austin (UT-Austin). Although the full sensor suite did not reach field-deployment readiness, the system-level integration achieved in this project establishes a validated pathway for future incorporation of advanced microsensors.

47 OTHER INSTRUMENTATION↗

Achieving the End State for the Pahute Mesa Corrective Action Units at the Nevada National Security Site - 20355

Underground nuclear testing at the Nevada National Security Site (NNSS) ended in 1992. To address the impact of radionuclide contamination from underground nuclear testing on the groundwater resources of Nevada, the U.S. Department of Energy (DOE) Environmental Management (EM) Nevada Program created the Underground Test Area (UGTA) activity to characterize the radionuclides in groundwater, understand the nature and extent of radionuclide migration, and forecast the distribution of radionuclides in groundwater for 1,000 years. The UGTA activity is regulated by the Federal Facility Agreement and Consent Order (FFACO), an agreement negotiated between the Nevada Division of Environmental Protection (NDEP), DOE, and the U.S. Department of Defense (DoD). DOE is close to achieving the end state (closure in place with monitoring and institutional control) for three of the five UGTA corrective action units (CAUs) on the NNSS. A number of challenges remain to achieve the end state of the other two CAUs, both located on Pahute Mesa. Pahute Mesa was the location of 82 underground nuclear tests, less than 10% of the total number of tests on the NNSS. Yet, Pahute Mesa contains slightly more than 60% of the total radionuclides (in curies). Based on groundwater sampling in monitoring wells, two radionuclide plumes have migrated several kilometers (km) in groundwater from selected test cavities and have crossed the boundary of the NNSS (yet remain within the boundaries of Federally controlled land). The path to achieve the end state continues to evolve as more data are collected and a better understanding of radionuclide migration in groundwater is developed. DOE has invested in drilling and sampling more than 50 characterization and monitoring groundwater wells over the past 25 years. The data indicate that the primary radionuclide of concern is tritium as it is about 89% of the total radionuclide inventory (in curies). As well, only tritium has been measured in groundwater outside of cavities at concentrations exceeding the Safe Drinking Water Act (SDWA) standard. For one of the tritium plumes that has migrated across the NNSS boundary, the average rate of migration has been measured as about 45 meters (m) per year with the rate of migration at the leading edge of the plume of about 85 meters per year. At that rate of migration, the tritium plume will decay to safe levels and not reach the publicly accessible environment at concentrations above the SDWA standard. Other radionuclides, at concentrations below the SDWA standards, will be monitored to ensure they remain at safe levels. Consequently, the end state path forward for Pahute Mesa has evolved to take full advantage of the data from the monitoring network to constrain uncertainty in model forecasts and to reduce reliance on probabilistic simulations. The focus of the end state approach relies on developing a monitoring well network that is protective of human health by increasing confidence that no radionuclide plume in the groundwater will migrate undetected to the accessible environment, located about 22 km from the nearest up-gradient underground nuclear test. Using the measured data to remove uncertainty, the evaluation of radionuclide migration from Pahute Mesa is directed toward meeting the goals of the end state. (authors)

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗

After Action Report: Specific Manufacturing Capability 2014 Evaluated Drill October 29, 2014

On October 29, 2014, the Specific Manufacturing Capability (SMC) facility located at the Idaho National Laboratory (INL) conducted its annual evaluated emergency drill. As a result, this after action report is required by DOE O 151.1C, “Comprehensive Emergency Management System.” The SMC facility, in coordination with other onsite organizations, and the Department of Energy Idaho Operations Office (DOE ID) conducted an annual facility emergency drill to demonstrate the ability to implement the requirements of DOE O 151.1C, “Comprehensive Emergency Management System.” The INL contractor, Battelle Energy Alliance, LLC (BEA) in coordination with other onsite organizations, conducted operations and demonstrated proper response measures to mitigate an event and protect the health and safety of onsite personnel, the environment, and property. Report data was collected from multiple sources, including documentation generated during drill response, critiques conducted immediately after terminating the drill, and evaluation critiques.

99 GENERAL AND MISCELLANEOUS↗

Utah FORGE: Well Data for Student Competition

Well 58-32 (previously labeled MU-ESW1) was drilled near Milford Utah during Phase 2B of the FORGE Project to confirm geothermal reservoir characteristics met requirements for the final FORGE site. Well Accord-1 was drilled decades ago for geothermal exploration purposes. While the conditions encountered in the well were not suitable for developing a conventional hydrothermal system, the information obtained suggested the region may be suitable for an enhanced geothermal system. Geophysical well logs were collected in both wells to obtain useful information regarding there nature of the subsurface materials. For the recent testing of 58-32, the Utah FORGE Project contracted with the well services company Schlumberger to collect the well logs.

15 GEOTHERMAL ENERGY↗

Clustered BSRs: Evidence for gas hydrate-bearing turbidite complexes in folded regions, example from the Perdido Fold Belt, northern Gulf of Mexico

We detail previously undocumented but extensive gas hydrate accumulations in the mouth of Perdido Canyon in the northern Gulf of Mexico. The accumulations are located within central parts of structural domes (four-way closures) and are characterized by stacked, high-amplitude bottom simulating reflections (BSRs) that we call clustered BSRs. Seismic data from Perdido Canyon show two clustered BSRs associated with turbidite sequences within two dome folds formed from tectonic folding and salt diapir rise. The northwestern (NW) and southeastern (SE) clustered BSRs have aerial extents of ~25 km2 and 50 km2, respectively. Well log data confirm gas hydrate occurs above the NW clustered BSR, within a 225 m-thick consistently high-resistivity interval that we interpret as gas hydrate in near-vertical fractures and turbidite sands. The SE dome is only drilled at the edge of the BSR; nevertheless, the well log data indicate that a 30 m-thick gas hydrate accumulation is present. Gas chromatographic logs in both domes suggest a gradual transition from predominantly microbial gas below the BSR (500–1000 m below seafloor (mbsf)) to thermogenic gas at 1000–2000 mbsf. Based on the well log data and seismic stratigraphic analysis, we find gas hydrate is concentrated in fractures in marine mud, as well as in the pores of submarine fan turbidities, where saturations reach as high as 75%. An estimate of the total gas hydrate-bound gas volume at standard temperature and pressure is between 0.04 and 0.17 trillion cubic meters (TCM) assuming average hydrate saturation of 5-20% in a ~45 m thick turbidite sand unit above the Perdido Canyon BSR area. Measured BSR extent and gas volume estimates indicate that the NW and SE reservoirs are among the largest gas hydrate occurrences known in the Gulf of Mexico.

58 GEOSCIENCES↗

Geomechanical Study of Bakken Formation for Improved Oil Recovery

On October 1, 2008 US DOE-sponsored research project entitled “Geomechanical Study of Bakken Formation for Improved Oil Recovery” under agreement DE-FC26-08NT0005643 officially started at The University of North Dakota (UND). This is the final report of the project; it covers the work performed during the project period of October 1, 2008 to December 31, 2013. The objectives of this project are to outline the methodology proposed to determine the in-situ stress field and geomechanical properties of the Bakken Formation in Williston Basin, North Dakota, USA to increase the success rate of horizontal drilling and hydraulic fracturing so as to improve the recovery factor of this unconventional crude oil resource from the current 3% to a higher level. The success of horizontal drilling and hydraulic fracturing depends on knowing local in-situ stress and geomechanical properties of the rocks. We propose a proactive approach to determine the in-situ stress and related geomechanical properties of the Bakken Formation in representative areas through integrated analysis of field and well data, core sample and lab experiments. Geomechanical properties are measured by AutoLab 1500 geomechanics testing system. By integrating lab testing, core observation, numerical simulation, well log and seismic image, drilling, completion, stimulation, and production data, in-situ stresses of Bakken formation are generated. These in-situ stress maps can be used as a guideline for future horizontal drilling and multi-stage fracturing design to improve the recovery of Bakken unconventional oil.

Diagnostics/Imaging↗