GC54A-01 16:00h
Comparison of Gas Flux and Soil Gas Composition at Two Oil Fields: Rangely, Colorado With CO$_{2}$-EOR, and Teapot Dome, Wyoming at Baseline Condition
Carbon Dioxide sequestration in spent oil and gas fields will likely be a significant early option that has economic advantages. A concern is the potential for gas microseepage under the overpressured conditions necessary for operation. A comparison was made between the overpressured Rangely, Colorado CO$_{2}$-EOR operation and the underpressured Teapot Dome oil field in Wyoming, which is proposed for CO$_{2}$ sequestration experimentation. Overpressure is important in driving the migration of relatively inert CH$_{4}$ from the reservoir environment, contrasting with more water soluble and reactive CO$_{2}$. Fluxes of CO$_{2}$ into the atmosphere under winter conditions of low soil biological activity averaged 302 and 228 mg m$^{2}$day$^{-1}$, with standard deviations of 1134 and 187 mg m$^{2}$day$^{-1}$, respectively, for Rangely and Teapot Dome. Average fluxes of CH$_{4}$ were 25 and 0.14 mg m$^{2}$day$^{-1}$, with standard deviations of 135 and 0.33 mg m$^{2}$day$^{-1}$, respectively for Rangely and Teapot Dome. Shallow soil gas composition exhibited similar large differences for CH$_{4}$. Median values were more similar at the two fields, reflecting high rates of microseepage at a few locations of those sampled. Stable carbon isotope measurements aided in the recognition of anomalous areas. Ten-meter deep holes were augured for nested soil gas sampling at selected locations of interest for more thorough characterization. Both areas of gas microseepage and background were investigated. In anomalous locations, a substantial proportion of deep-sourced CH$_{4}$ was bacterially oxidized in the unsaturated zone, producing isotopically distinctive and radiocarbon-depleted CO$_{2}$. Carbon isotopic composition of surface materials, such as calcite, caliche, vegetation, soil organic and inorganic matter are essential in the characterization of processes operating in the near-surface.
GC54A-02 16:15h
A Survey of Measurement, Mitigation, and Verification Field Technologies for Carbon Sequestration Geologic Storage
The U.S. Department of Energy's (U.S. DOE's) Carbon Sequestration Program is developing state-of-the-science technologies for measurement, mitigation, and verification (MM&V) in field operations of geologic sequestration. MM&V of geologic carbon sequestration operations will play an integral role in the pre-injection, injection, and post-injection phases of carbon capture and storage projects to reduce anthropogenic greenhouse gas emissions. Effective MM&V is critical to the success of CO$_{2}$ storage projects and will be used by operators, regulators, and stakeholders to ensure safe and permanent storage of CO$_{2}$. In the U.S. DOE's Program, Carbon sequestration MM&V has numerous instrumental roles: Measurement of a site's characteristics and capability for sequestration; Monitoring of the site to ensure the storage integrity; Verification that the CO$_{2}$ is safely stored; and Protection of ecosystems. Other drivers for MM&V technology development include cost-effectiveness, measurement precision, and frequency of measurements required. As sequestration operations are implemented in the future, it is anticipated that measurements over long time periods and at different scales will be required; this will present a significant challenge. MM&V sequestration technologies generally utilize one of the following approaches: below ground measurements; surface/near-surface measurements; aerial and satellite imagery; and modeling/simulations. Advanced subsurface geophysical technologies will play a primary role for MM&V. It is likely that successful MM&V programs will incorporate multiple technologies including but not limited to: reservoir modeling and simulations; geophysical techniques (a wide variety of seismic methods, microgravity, electrical, and electromagnetic techniques); subsurface fluid movement monitoring methods such as injection of tracers, borehole and wellhead pressure sensors, and tiltmeters; surface/near surface methods such as soil gas monitoring and infrared sensors and; aerial and satellite imagery. This abstract will describe results, similarities, and contrasts for funded studies from the U.S. DOE's Carbon Sequestration Program including examples from the Sleipner North Sea Project, the Canadian Weyburn Field/Dakota Gasification Plant Project, the Frio Formation Texas Project, and Yolo County Bioreactor Landfill Project. The abstract will also address the following: How are the terms ``measurement,'' ``mitigation''and ``verification'' defined in the Program? What is the U.S. DOE's Carbon Sequestration Program Roadmap and what are the Roadmap goals for MM&V? What is the current status of MM&V technologies?
GC54A-03 INVITED 16:30h
MM&V Studies at West Pearl Queen Carbon Sequestration Pilot Site
A pilot sequestration test has recently been performed in a depleted oil reservoir near Hobbs, NM. About 2,100 tons of CO$_{2}$ were injected into the West Pearl Queen reservoir. The site has been characterized geologically by information from well logs. Additionally, as potential CO$_{2}$ leakage pathways are a concern, a lineament analysis and ground-penetration radar (GPR) study have been performed to help understand better the near-surface geology. As part of the MM&V study, three perfluorocarbon tracers (PFTs) were injected for three twelve-hour periods with the carbon dioxide. Capillary absorption tube samplers (CATS), used to detect the presence of PFTs in small quantities, were located near the surface in a circular pattern stretching about 300m from the injection well. The CATS were sampled at different times to determine if any changes would be seen as injection progressed. From the geologic data that has been collected, a geomechanical model and a flow model have been developed for the site. The geomechanical model has been used to help predict the deformations caused in the reservoir and surrounding rock and identify potential fracture zones. The flow of CO$_{2}$ and tracer has been modeled at the site to help identify potential leakage pathways. Near the surface, in the vadose zone, the fluids are modeled by diffusion in one model, and by a combination of advection and diffusion in another. A reservoir simulator has been used to model flow of the carbon dioxide in the reservoir and overburden strata. The presentation will contain lessons learned from this MM&V study.
GC54A-04 INVITED 16:45h
Geophysical Monitoring for the Frio Pilot CO2 Injection Test
The Frio Pilot test involves injection of approximately 3000 tons of CO2 into the brine-saturated Frio formation at a depth of approximately 1500 m at a test site located northeast of Houston. Interpretation of 3-D seismic coupled with petrophysical analyses and other geologic data showed that the test site is located in a small fault block off the flank of a salt dome. The CO2 is injected into a 10 m thick sand layer in an interval of alternating sand and shale layers overlain by the 75 m thick Anahuac shale. Well logs in the new well provide data to confirm test site stratigraphy as well as data needed for interpretation of geophysical monitoring measurements. Geophysical monitoring, which is augmented by hydrologic pressure measurements and geochemical sampling, involves time-lapse measurements, incorporating both surface and borehole techniques. A vertical seismic profiling (VSP) survey was designed for both monitoring and imaging the structure in the injection volume, and involved 8 explosive shot points at 100 - 1500 m offsets. An 80 level receiver string with 240 3-component sensors was used. Crosswell surveys involved P- and S-wave seismic and electromagnetic (EM) measurements (between steel-cased wells) at 1.5 m spacing over a 75 m interval. EM measurements were at 50 and 80Hz, and an orbital-vibrator seismic source provided seismic data in the 150Hz frequency range. Joint interpretation of crosswell seismic and EM with appropriate rock physics models can potentially provide quantitative information on CO2 saturation between boreholes.
GC54A-05 17:00h
Monitoring of CO$_{2}$ Surface Leakage at the Frio Pilot Injection Site
Geologic carbon sequestration is a method of greenhouse gas mitigation in which CO$_{2}$ is captured directly from major emission sources and stored beneath the ground. Among the proposed storage locations are active and depleted oil and natural gas reservoirs, unmineable coal seams, and deep saline aquifers. The success of such activities depends greatly on the ability to contain the CO$_{2}$ for long periods of time (up to thousands of years). For this reason, it is important to be able to measure the leakage rate of CO$_{2}$ to the surface following injection of CO$_{2}$. Monitoring the leakage of CO$_{2}$ is a challenging task, due to the small expected concentrations above a leaking reservoir as well as the relatively large background of CO$_{2}$ present in the atmosphere. A suite of near-surface monitoring techniques has been developed at the National Energy Technology Laboratory to estimate leakage rates and evaluate storage integrity. The techniques include the detection of injected tracer molecules, direct measurement of CO$_{2}$ soil flux, soil gas analysis, and carbon isotope analysis from soil gas CO$_{2}$. These techniques are currently being employed in Eastern Texas in cooperation with the Frio pilot injection project, headed by the Texas Bureau of Economic Geology at the University of Texas. Baseline measurements have been made in the area surrounding the injection well, and will be repeated following CO$_{2}$ injection. This presentation will include description of the monitoring techniques as well as a summary of the results to date.
GC54A-06 17:15h
Measuring Water in Bioreactor Landfills
Methane is an important greenhouse gas, and landfills are the largest anthropogenic source in many developed countries. Bioreactor landfills have been proposed as one means of abating greenhouse gas emissions from landfills. Here, the decomposition of organic wastes is enhanced by the controlled addition of water or leachate to maintain optimal conditions for waste decomposition. Greenhouse gas abatement is accomplished by sequestration of photosynthetically derived carbon in wastes, CO2 offsets from energy use of waste derived gas, and mitigation of methane emission from the wastes. Maintaining optimal moisture conditions for waste degradation is perhaps the most important operational parameter in bioreactor landfills. To determine how much water is needed and where to add it, methods are required to measure water within solid waste. However, there is no reliable method that can measure moisture content simply and accurately in the heterogeneous environment typical of landfills. While well drilling and analysis of solid waste samples is sometimes used to determine moisture content, this is an expensive, time-consuming, and destructive procedure. To overcome these problems, a new technology recently developed by hydrologists for measuring water in the vadose zone --- the partitioning tracer test (PTT) --- was evaluated for measuring water in solid waste in a full-scale bioreactor landfill in Yolo County, CA. Two field tests were conducted in different regions of an aerobic bioreactor landfill, with each test measuring water in $\approx$ 250 ft$^3$ of solid waste. Tracers were injected through existing tubes inserted in the landfill, and tracer breakthrough curves were measured through time from the landfill's gas collection system. Gas samples were analyzed on site using a field-portable gas chromatograph and shipped offsite for more accurate laboratory analysis. In the center of the landfill, PTT measurements indicated that the fraction of the pore space filled with water was 29%, while the moisture content, the mass of water divided by total wet mass of solid waste, was 28%. Near the sloped sides of the landfill, PTT results indicated that only 7.1% of the pore space was filled with water, while the moisture content was estimated to be 6.9%. These measurements are in close agreement with gravimetric measurements made on solid waste samples collected after each PTT: moisture content of 27% in the center of the landfill and only 6% near the edge of the landfill. We discuss these measurements in detail, the limitations of the PTT method for landfills, and operational guidelines for achieving unbiased measurements of moisture content in landfills using the PTT method.
GC54A-07 17:30h
Implications of Soil Gas Survey Results Over Known Carbon Dioxide Systems for Long-term Monitoring
Soil gas surveys have been carried out over three areas with natural occurrences of carbon dioxide on the Colorado Plateau. At Farnham Dome, Utah, and Springerville-St. Johns, Arizona, carbon dioxide reservoirs occur at 600 - 800 m depth, but no anomalous soil gas carbon dioxide flux was detected. Evidence of widespread vein calcite at the surface (Farnham Dome) and travertine deposits (Springerville-St. Johns) suggest that the fields may have leaked carbon dioxide-rich fluids in the past. At Springerville-St. Johns, there is a significant outflow of high-bicarbonate water to the surface, which may be the main mechanism that carbon dioxide is reaching the surface today. carbon dioxide fluxes as high as 40 g m-2 day-1 in swampy ground adjacent to bicarbonate spring outflows at Springerville-St. Johns are attributed to shallow soil reactions rather than to a deep upflow. A 500 m depth, non-producing well at Springerville-St. Johns responds barometrically, sucking in air during pressure highs, and discharging a carbon dioxide-air mixture during pressure lows. Results from a third soil gas survey area of natural carbon dioxide-water discharges along fault zones in central Utah will also be presented. The unexpected results indicate that soil gas monitoring may not be easy or simple.
GC54A-08 17:45h
Southeast Regional Carbon Sequestration Partnership MMV Technologies for Geologic Sequestration
Successful measuring, monitoring and verification (MMV) of carbon sequestration is a classic multi-attribute problem - highly constrained and without a uniquely correct answer. Constraints include costs; the type of formation; the expected mode of sequestration (physical vs. chemical); the desired precision and accuracy of the measured data; the capabilities of the workers making the measurements; and the ability to convert the measured data to meaningful information. Further, considerations relating to the safety of workers; public safety; environmental protection; detection of and response to physical changes in the sequestering formation may also act as constraints. The weight of these constraints will also vary depending on the specific location being considered. Thus, there will not be a uniquely optimal suite of measurement technologies; rather, almost always a trade-off will result. This implies that very dissimilar technologies may be employed even at similar geologic sites. The Southeastern Regional Carbon Sequestration Partnership - SECARB - is being led by the Southern States Energy Board. As part of its program, SECARB is identifying appropriate suites of technologies for use in planned geologic sequestration projects. As part of this process, SECARB is identifying technologies for the characterization of the formation (prior to sequestration); for use during transport and delivery of carbon into the formation; and for monitoring the effectiveness of sequestration both short- and long-term. SECARB is considering both technologies that are field-ready today, and technologies that are in the later stages of development. We are also considering the unique characteristics of the possible sites in our region. In the following, we provide candidate suites of measurement technologies for use in three types of sequestration projects possible in our region: 1. Enhanced coalbed methane recovery 2. Enhanced oil recovery 3. Sequestration in brine formations
http://www.secarbon.org