Christine Doughty
Lawrence Berkeley National Laboratory, Earth Science Division, Department Member
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Author(s): Freifeld, B.; Doughty, C.; Walker, J.; Kryder, L.; Gilmore, K.; Finsterle, S.; Sampson, J.
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ECO2N V2.0 is a fluid property module for the TOUGH2 simulator (Version 2.1) that was designed for applications to geologic sequestration of CO2 in saline aquifers and enhanced geothermal reservoirs. ECO2N V2.0 is an enhanced version of... more
ECO2N V2.0 is a fluid property module for the TOUGH2 simulator (Version 2.1) that was designed for applications to geologic sequestration of CO2 in saline aquifers and enhanced geothermal reservoirs. ECO2N V2.0 is an enhanced version of the previous ECO2N V1.0 module (Pruess, 2005). It expands the temperature range up to about 300oC whereas V1.0 can only be used for temperatures below about 110oC. V2.0 includes a comprehensive description of the thermodynamic and thermophysical properties of H2O - NaCl - CO2 mixtures, that reproduces fluid properties largely within experimental error for the temperature, pressure and salinity conditions 10 °C < T < 300 °C, P < 600 bar, and salinity up to halite saturation. This includes density, viscosity, and specific enthalpy of fluid phases as functions of temperature, pressure, and composition, as well as partitioning of mass components H2O, NaCl and CO2 among the different phases. In particular, V2.0 accounts for the effects of water o...
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We investigate the physical processes that occur during the sequestration of CO2 in brine-bearing geologic formations using TOUGH2. An equation of state package that treats a two-phase (liquid, gas), three-component (water, salt, and CO2)... more
We investigate the physical processes that occur during the sequestration of CO2 in brine-bearing geologic formations using TOUGH2. An equation of state package that treats a two-phase (liquid, gas), three-component (water, salt, and CO2) system is employed. CO2 is injected in a supercritical state that has a much lower density and viscosity than the liquid brine it displaces. In situ, the supercritical CO2 forms a gas-like phase, and also partially dissolves in the aqueous phase. Chemical reactions between CO2 and rock minerals that could potentially contribute to mineral trapping of CO2 are not included. The geological setting considered is a fluvial/deltaic formation that is strongly heterogeneous, making preferential flow a significant effect, especially when coupled with the strong buoyancy forces acting on the gas-like CO2 plume. Key model development concerns include vertical and lateral grid resolution, grid orientation effects, and the choice of characteristic curves
We investigate the physical processes that occur during the sequestration of CO2 in brine-bearing geologic formations using TOUGH2. An equation of state package that treats a two-phase (liquid, gas), three-component (water, salt, and CO2)... more
We investigate the physical processes that occur during the sequestration of CO2 in brine-bearing geologic formations using TOUGH2. An equation of state package that treats a two-phase (liquid, gas), three-component (water, salt, and CO2) system is employed. CO2 is injected in a supercritical state that has a much lower density and viscosity than the liquid brine it displaces. In situ, the supercritical CO2 forms a gas-like phase, and also partially dissolves in the aqueous phase. Chemical reactions between CO2 and rock minerals that could potentially contribute to mineral trapping of CO2 are not included. The geological setting considered is a fluvial/deltaic formation that is strongly heterogeneous, making preferential flow a significant effect, especially when coupled with the strong buoyancy forces acting on the gas-like CO2 plume. Key model development concerns include vertical and lateral grid resolution, grid orientation effects, and the choice of characteristic curves
Author(s): Doughty, Christine; Benson, Sally M. | Abstract: Making the most efficient use of the underground pore space is one strategy for maximizing the safety and effectiveness of storage in saline formations. By using a large fraction... more
Author(s): Doughty, Christine; Benson, Sally M. | Abstract: Making the most efficient use of the underground pore space is one strategy for maximizing the safety and effectiveness of storage in saline formations. By using a large fraction of the available pore volume, the spatial dimensions of the CO2 plume can be kept to a minimum thereby limiting the number of abandoned wells potentially encountered by the plume, decreasing the footprint over which monitoring is required and increasing the capacity of a storage formation. Today, estimates of the pore volume available for storage range from as low as 1-2% of the formation, to as high as 20-30%. The lower estimates do not arise from an intrinsic lack of pore space, but reflect the difficulty of accessing certain parts of the formation. The purpose of this paper is to explore strategies for increasing the fraction of the pore space that is accessed by CO2 and is available for storage. A new version of the numerical simulator TOUGH2, ...
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Author(s): Doughty, Christine; Benson, Sally M. | Abstract: Making the most efficient use of the underground pore space is one strategy for maximizing the safety and effectiveness of storage in saline formations. By using a large fraction... more
Author(s): Doughty, Christine; Benson, Sally M. | Abstract: Making the most efficient use of the underground pore space is one strategy for maximizing the safety and effectiveness of storage in saline formations. By using a large fraction of the available pore volume, the spatial dimensions of the CO2 plume can be kept to a minimum thereby limiting the number of abandoned wells potentially encountered by the plume, decreasing the footprint over which monitoring is required and increasing the capacity of a storage formation. Today, estimates of the pore volume available for storage range from as low as 1-2% of the formation, to as high as 20-30%. The lower estimates do not arise from an intrinsic lack of pore space, but reflect the difficulty of accessing certain parts of the formation. The purpose of this paper is to explore strategies for increasing the fraction of the pore space that is accessed by CO2 and is available for storage. A new version of the numerical simulator TOUGH2, ...
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Faults and fractures filled with hot brine are difficult to image and characterize at EGS sites because they are practically indistinguishable from surrounding matrix heterogeneity using traditional seismic and well-logging tools. We are... more
Faults and fractures filled with hot brine are difficult to image and characterize at EGS sites because they are practically indistinguishable from surrounding matrix heterogeneity using traditional seismic and well-logging tools. We are investigating the use of CO2 injection and production (push-pull) for contrast enhancement of faults and fractures for better characterization by active seismic and wireline well-logging approaches. In addition, we are modeling the pressure- and flow-rate-transient response of the system during push-pull to augment geophysical fault and fracture characterization. The approach consists of numerical simulation and feasibility assessment using conceptual models typical of EGS sites. Faults and fractures in the deep subsurface tend to occur in zones and sets with associated damage and gouge regions that are parallel to the slip plane(s) and that provide a larger volume for uptake of CO2 than the volume provided by the slip plane(s) alone. CO2 injected f...
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Faults and fractures filled with hot brine are difficult to image and characterize at EGS sites because they are practically indistinguishable from surrounding matrix heterogeneity using traditional seismic and well-logging tools. We are... more
Faults and fractures filled with hot brine are difficult to image and characterize at EGS sites because they are practically indistinguishable from surrounding matrix heterogeneity using traditional seismic and well-logging tools. We are investigating the use of CO2 injection and production (push-pull) for contrast enhancement of faults and fractures for better characterization by active seismic and wireline well-logging approaches. In addition, we are modeling the pressure- and flow-rate-transient response of the system during push-pull to augment geophysical fault and fracture characterization. The approach consists of numerical simulation and feasibility assessment using conceptual models typical of EGS sites. Faults and fractures in the deep subsurface tend to occur in zones and sets with associated damage and gouge regions that are parallel to the slip plane(s) and that provide a larger volume for uptake of CO2 than the volume provided by the slip plane(s) alone. CO2 injected f...
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Author(s): Myer, Larry; Benson, Sally; Cole, David; Daley, Tom; Doughty, Christine; Dutton, Alan; Freifeld, Barry; Gunter, William; Holtz, Mark; Hovorka, Susan; Hoversten, Mike; Kennedy, B. Mack; Kharaka, Yousif; Knauss, Kevin; Knox,... more
Author(s): Myer, Larry; Benson, Sally; Cole, David; Daley, Tom; Doughty, Christine; Dutton, Alan; Freifeld, Barry; Gunter, William; Holtz, Mark; Hovorka, Susan; Hoversten, Mike; Kennedy, B. Mack; Kharaka, Yousif; Knauss, Kevin; Knox, Paul; Majer, Ernie; Phelps, Tommy; Pruess, Karsten; Robinson, John
Author(s): Myer, Larry; Benson, Sally; Cole, David; Daley, Tom; Doughty, Christine; Dutton, Alan; Freifeld, Barry; Gunter, William; Holtz, Mark; Hovorka, Susan; Hoversten, Mike; Kennedy, B. Mack; Kharaka, Yousif; Knauss, Kevin; Knox,... more
Author(s): Myer, Larry; Benson, Sally; Cole, David; Daley, Tom; Doughty, Christine; Dutton, Alan; Freifeld, Barry; Gunter, William; Holtz, Mark; Hovorka, Susan; Hoversten, Mike; Kennedy, B. Mack; Kharaka, Yousif; Knauss, Kevin; Knox, Paul; Majer, Ernie; Phelps, Tommy; Pruess, Karsten; Robinson, John
Mathematical modeling of a ponded infiltration test conducted at the Box Canyon site in southeastern Idaho has been carried out to assess understanding of infiltration in a fractured basalt vadose zone and to evaluate the adequacy of... more
Mathematical modeling of a ponded infiltration test conducted at the Box Canyon site in southeastern Idaho has been carried out to assess understanding of infiltration in a fractured basalt vadose zone and to evaluate the adequacy of conceptual and numerical models. A key question addressed is how the fracture-pattern geometry and fracture connectivity within a single basalt flow of the Snake River Plain basalt affect the pattern of water infiltration. The two-dimensional numerical model uses half-meter discretization to represent a 20 m by 20 m cross-section througli the field site. The model extends from the ground surface to a perched water body, with explicit but highly simplified representation of major fractures and other important hydrogeologic features. The model adequately reproduces the majority of the field observations, confirming the notion that infiltration is largely fracture-controlled. Comparison to results obtained using a geostatistical approach to describe subsur...
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The feasibility of CO2 injection in a reservoir of the Bécancour region was investigated using 2D radial numerical simulations with TOUGH2/ECO2N. To optimize the CO2 injec¬tion rate and the duration of injection, we carried out... more
The feasibility of CO2 injection in a reservoir of the Bécancour region was investigated using 2D radial numerical simulations with TOUGH2/ECO2N. To optimize the CO2 injec¬tion rate and the duration of injection, we carried out sensitivity analyses considering different values of completion interval for the single injection well, rock compressibility, and the ratio of vertical and horizontal permeabilities. Simulations took into account Bécancour reser¬voir conditions, in which injection pressure was limited below the fracturing threshold, and sensitivity analyses provided indications of potential injection scenarios. To remain below fracturing pressure, we propose intermittent 5-year injection periods, with a mass injection rate up to 20 kg/s, alter¬nating with half-year periods without injection. This scenario may provide maximum CO2 storage in the aquifer. We also calculated CO2 storage capacities in different phases versus time. The effective apparent capacity and injec¬tion cap...
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Description/Abstract: The response of the two-reservoir system to reinjection was modeled assuming a semi-realistic vertical distribution of materials. Different depths of production and reinjection, and the possible influence of an... more
Description/Abstract: The response of the two-reservoir system to reinjection was modeled assuming a semi-realistic vertical distribution of materials. Different depths of production and reinjection, and the possible influence of an intervening layer of lower permeability ...
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ABSTRACT: Cross-borehole air-injection interference tests were conducted at the Box Canyon site near the Idaho National Engineering and Environmental Laboratory in order to assess the pneumatic connectivity of unsaturated fractured... more
ABSTRACT: Cross-borehole air-injection interference tests were conducted at the Box Canyon site near the Idaho National Engineering and Environmental Laboratory in order to assess the pneumatic connectivity of unsaturated fractured basalt, and determine zones of ...
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Monitoring and modeling migration of injected CO2 in the subsurface is critical for assessing the risk of leakage from geologic carbon sequestration sites, but it is also very challenging. Integrating complementary hydrological and... more
Monitoring and modeling migration of injected CO2 in the subsurface is critical for assessing the risk of leakage from geologic carbon sequestration sites, but it is also very challenging. Integrating complementary hydrological and geophysical monitoring data in a coupled hydrogeophysical inversion can help to address this challenge. We consider a synthetic CO2 injection study to analyze the effect of adding cross-borehole electrical resistance and seismic data to inversions of pressure and gas-composition data. The ...