The BSCSP is conducting a large volume injection field project within Kevin (pronounced kee-vin) Dome in north-central Montana (Figure 1), with the Duperow (dolostone) Formation as the primary targeted storage reservoir. Naturally-occurring CO2 is trapped in the Duperow at the top of Kevin Dome, but large areas of the Duperow around the flanks of the dome are saline-saturated, do not contain CO2, and are available for additional CO2 storage. Over a four-year period, the project will use up to five production wells to extract one million metric tons of CO2 from the top of the dome, compress and transport the CO2 approximately six miles in a 2-inch underground pipeline, and inject it via a single injection well into the Duperow formation downgradient from the CO2 reservoir (Figure 2). Four monitoring wells will be completed into the Duperow in the vicinity of the injection well. Hydrologic, geochemical, geomechanical, and geophysical data - including comprehensive 3-D, 9-component seismic surveys of the CO2 production/injection areas, crosswell seismic surveys, and vertical seismic profiling - will be obtained and used to monitor, describe, and predict the behavior of the CO2 in the formation. After the 4-year injection period, BSCSP will continue to monitor the site for an additional two years. At that time, all commercially-viable CO2 production wells (including, perhaps, the injection well) would be transferred to a private-sector partner (Vecta Oil & Gas, Ltd.), with all other wells being properly plugged. All data will be incorporated into the BSCSP’s existing graphical information system (GIS) framework and the Big Sky Carbon Atlas as well as the U.S. 2012 Carbon Utilization and Storage Atlas. In addition, the data collection techniques and results of the study will be incorporated into DOE’s Best Practices Manuals. Information will be disseminated to the public and stakeholders throughout all phases of the project. Description of Geology
Kevin Dome is a large, anticlinal structural culmination located along the Sweetgrass Arch in north-central Montana. The geology of Kevin Dome is well understood due to its history of oil and gas development; however, the characteristics of the Duperow Formation within the dome are less well-known because it occurs deeper and stratigraphically lower than past and current oil and gas production. The dome closure covers approximately 700 square miles at the Devonian Duperow stratigraphic level with approximately 750 feet of structural relief. Naturally occurring CO2 has been documented from several oil and gas wells that have tested the Duperow over the last 50 years, but the volume, continuity of the trapped gas, and circumstances of its entrapment have been poorly understood. Below the CO2 gas in the trapped reservoirs of the Duperow Formation within the Kevin Dome is a saline aquifer having very poor water quality (greater than 20,000 ppm of total dissolved solids). The combination of a natural trap ensuring good overlying caprock, formation compatibility with CO2, the large volume of this static trap, the poor quality of contained water, the proximity to present and future sources of anthropogenic CO2, and the similarity of this feature to other large domes suggest this geologic feature is of great regional significance for understanding carbon storage potential and capacity. Tightlycompacted layers at the top of the Duperow formation will serve as an immediate seal for the injected CO2, while the 175 feet thick, regionally-extensive Potlatch Anhydrite will provide an effective caprock for the entire Kevin Dome injection site. Injection Site Description
The injection site is located in a rural section of Toole County, Montana (pop. ~5,267), about 8-miles east of the village of Sunburst (pop. ~375) and 8 miles south of the Canadian border. The CO2 production well site is approximately 6 miles south of the injection site, 12-miles northeast of the town of Kevin (pop. ~154) and 18 miles north of the county seat of Shelby (pop. ~3,376). The wells, compressor station, and pipelines will be located on lands owned by the State of Montana and/or lands held in fee title by private landowners; BSCSP will work closely with these owners for access. The seismic work would be performed on private, state, and U.S. government owned lands pending landowner permission or acquisition of required state and Federal permits. Source of CO2
Large volumes of naturally occurring CO2 are trapped in the Duperow Formation, which has closure under the Kevin Dome. The BSCSP will produce this naturally occurring CO2 for large-scale injection by drilling up to five CO2 production wells into the formation beneath the top of the dome. The purity of the CO2 will be determined once the first production well is drilled. The extracted CO2 will then be transported by pipeline to the single injection well drilled into the flank of the dome, where it will be injected into the Duperow and perhaps the Souris River formations (Figure 2). Injection Operations
CO2 will be injected through a single wellbore, and initial data from the targeted injection zone of the Duperow suggests the interval has 12 percent porosity and greater than 50 millidarcy permeability. These values should allow for injection volumes in the range of 12 to 13 MMcf/day, or approximately 250,000 metric tons of CO2 per year, over a four-year period. The CO2 production wells are expected to recover CO2 at a pressure and temperature of approximately 1,100 lbs. and 96°F respectively. The CO2 will then be compressed via a compressor station at the production well site and transported through a pipeline to the injection site approximately six miles to the north. Simulation and Monitoring of CO2
The commercially available PETRA software will be used to construct the basic geological framework, augmented by geophysical interpretation of available data using Kingdom geophysical interpretation software, and then uploaded into PETREL software as a precursor to creating a basic 3-D flow model. The TOUGH series of codes developed by Lawrence Berkeley National Laboratory will be the primary means of simulating multiphase flow, CO2 transport, and geochemical reactions along the flow path, although other model types may be employed for comparison purposes. Core samples taken from the CO2 gas cap and brine-filled flank of the dome will be tested in the laboratory to determine brine chemical and rock mineral composition and provide data for initializing and calibrating the geochemical model. The BSCSP plans to employ an extensive and novel set of monitoring technologies at the Kevin Dome site. The methods include borehole (downhole and distributed pressure and temperature sensing, cased hole logs such as pulsed neutron) and seismic methods (crosswell seismic, 3-D, 9-component surface seismic, and multi-component vertical seismic profiling), core analyses, a suite of geochemical methods, injected and natural tracer studies, atmospheric CO2 monitoring, soil gas sampling, and surface and ground water monitoring. The Kevin Dome project offers several unusual monitoring and validation opportunities due to the presence of a large natural accumulation of CO2 and the unique geophysical capabilities and expertise of the BSCSP partners. For example, Vecta Oil and Gas has developed a skill set for processing, interpretation, and integration of nine-component data to image complex stratigraphy; Lawrence Berkeley National Laboratory will employ a unique down-hole seismic source for the crosswell survey; Columbia University has extensive experience in performing experiments with 14C and other types of chemical tracers; and Idaho National Laboratory has developed a novel technique for using rare-earth element signatures as an environmental aqueous tracer to determine if formation fluids are leaking from the target reservoir into overlying formations or to measure the extent that CO2 displaced waters have migrated.
The U.S. Department of Energy Regional Carbon Sequestration Partnership (RCSP) Initiative consists of seven partnerships. The purpose of these partnerships is to determine the best regional approaches for permanently storing carbon dioxide (CO2) in geologic formations. Each RCSP includes stakeholders comprised of state and local agencies, private companies, electric utilities, universities, and nonprofit organizations. These partnerships are the core of a nationwide network helping to establish the most suitable technologies, regulations, and infrastructure needs for carbon storage. The partnerships include more than 400 distinct organizations, spanning 43 states and four Canadian provinces, and are developing the framework needed to validate geologic carbon storage technologies. The RCSPs are unique in that each one is determining which of the numerous geologic carbon storage approaches are best suited for their specific regions of the country and are also identifying regulatory and infrastructure requirements needed for future commercial deployment. The RCSP Initiative is being implemented in three phases, the Characterization Phase, Validation Phase, and Development Phase. In September 2003, the Characterization Phase began with the seven partnerships working to determine the locations of CO2 sources and to assess suitable locations for CO2 storage. The Validation Phase (2005–2012) focused on evaluating promising CO2 storage opportunities through a series of small scale field projects in the seven partnership regions. Finally, the Development Phase (2008-2020+) activities are proceeding and will continue evaluating how CO2 capture, transportation, injection, and storage can be achieved safely, permanently, and economically at large scales. These field projects are providing tremendous insight regarding injectivity, capacity, and containment of CO2 in the various geologic formations identified by the partnerships. Results and assessments from these efforts will assist commercialization efforts for future carbon storage projects in North America. The Big Sky Carbon Sequestration Partnership (BSCSP), led by Montana State University, includes more than 60 organizations and covers Idaho, Montana, eastern Oregon, South Dakota, eastern Washington, and Wyoming. The six states in the Big Sky Partnership region emit 146 million metric tons of CO2 annually stationary sources. There are large saline formations in the Big Sky region east of the Rocky Mountains and basalt formations in the western part capable of storing many billions of metric tons of CO2, equivalent to many hundreds of years’ worth of regional CO2 emissions. The BSCSP land area also includes vast acreage of agricultural, range, and forest lands that can be managed for greater storage of soil and biomass carbon. The Big Sky region is also rich in energy resources including coal, oil and gas, and renewables. Benefits
Improved understanding of the Kevin Dome geologic feature, which has great potential to serve as a northwestern U.S. carbon storage center because of its unique geologic properties, proximity to present and future sources of anthropogenic CO2, and similarity to other large domes in Montana.
Refinement of regional CO2 resource estimates, given that Kevin Dome and the Duperow formation are regionally significant geologic features.
Enhanced understanding of geochemistry related to CO2 exposure. Production well cores will provide geochemical information from millions of years of CO2 exposure and injection and monitoring well data will provide information on geochemical changes over the project timescale.
Improved understanding of geomechanical and geophysical characteristics of cap rocks in naturally occurring reservoirs and application of that data to potential geo-storage sites.
The ability to test advances in surface seismic imaging and pressure changes to monitor reservoir changes during removal of CO2 from an existing reservoir.
Improved understanding of the dome’s potential as a CO2 gas storage reservoir. First, to store CO2 captured from new clean energy plants, and second, to provide CO2 to mature oil fields in the immediate region of the dome for enhanced oil recovery projects.
Goals and Objectives
The primary objective of the DOE’s Carbon Storage Program is to develop technologies to safely and permanently store CO2 and reduce Greenhouse Gas (GHG) emissions without adversely affecting energy use or hindering economic growth. The Programmatic goals of Carbon Storage research are to: (1) develop and validate technologies to ensure 99 percent storage permanence; (2) develop technologies to improve reservoir storage efficiency while ensuring containment effectiveness; (3) support industry’s ability to predict CO2 storage capacity in geologic formations to within 30 percent; and (4) develop Best Practices Manuals (BPMs) for monitoring, verification, accounting, and assessment; site screening, selection, and initial characterization; public outreach, well management activities, and risk analysis and simulation. The goal of this large volume CO2 storage field project is to demonstrate that significant saline reservoirs, including some in geologic structural domes, are present in northern Montana and these storage formations are viable targets for storing a large fraction of the Big Sky region’s CO2 emissions. The overall research objectives include improving the understanding of injectivity, storage resources, and storage potential in a regionally significant formation and promoting the commercialization of future carbon storage projects. Specific operational objectives include:
Safely procuring, transporting, injecting and monitoring up to one million metric tons of CO2 into the target formation (Duperow) within Kevin Dome in northwest Montana.
Understanding the behavior of the injected CO2 within the formation and verifying and improving predictive models of CO2 behavior and monitoring, verification, and accounting (MVA) methodology.
Assessing and managing project risks during and after injection operations.
Disseminating information through public outreach and key stakeholder briefings.
Refining the regional characterization of carbon storage formations, sources, infrastructure, and storage estimates in geologic and terrestrial systems.
Developing best practices from lessons learned.
Investigating domes as early-stage targets for commercial storage.
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