TY - GEN
T1 - Effect of CO2 injectivity on enhanced shale gas recovery
AU - Li, Xiang
AU - Elsworth, Derek
N1 - Publisher Copyright:
Copyright © 2014 ARMA, American Rock Mechanics Association.
PY - 2014
Y1 - 2014
N2 - Shale gas has become an increasingly important source of natural gas (CH4) in the United States over the last decade. Due to its unconventional characteristics, injecting carbondioxide (CO2) to enhance shale gas recovery (ESGR) is a potentially feasible method to increase gas-yield while both affording a sink for CO2 and in reducing the potential for induced seismicity. This study examines CO2-ESGR to better understand its feasibility and effectiveness. We explore the roles of important coupled phenomena activated during gas substitution especially vigorous feedbacks between sorptive behavior and permeability evolution. Permeability and porosity evolution models developed for sorptive fractured coal are adapted to the component characteristics of gas shales. These adapted models are used to probe the optimization of CO2-ESGR for injection of CO2 at overpressures of OMPa, 4MPa and 8MPa to investigate magnitudes of elevated CH4 production, CO2 storage rate and capacity, and of CO2 early-breakthrough and permeability evolution in the reservoir. For the injection pressures selected, CH4 production was enhanced by 2.3%, 14.3%, 28.5%, respectively, over the case where CO2 is not injected. Distinctly different evolutions are noted for permeability in both fractures and matrix due to different dominating mechanisms. Fracture permeability increased by 1/3 for the injection scenarios due to the dominant influence of CH4 de-sorption over CO2 sorption. CO2 sequestration capacity was only of the order of 104 m3 when supercritical for a net recovery of CH4 of 108 m3.
AB - Shale gas has become an increasingly important source of natural gas (CH4) in the United States over the last decade. Due to its unconventional characteristics, injecting carbondioxide (CO2) to enhance shale gas recovery (ESGR) is a potentially feasible method to increase gas-yield while both affording a sink for CO2 and in reducing the potential for induced seismicity. This study examines CO2-ESGR to better understand its feasibility and effectiveness. We explore the roles of important coupled phenomena activated during gas substitution especially vigorous feedbacks between sorptive behavior and permeability evolution. Permeability and porosity evolution models developed for sorptive fractured coal are adapted to the component characteristics of gas shales. These adapted models are used to probe the optimization of CO2-ESGR for injection of CO2 at overpressures of OMPa, 4MPa and 8MPa to investigate magnitudes of elevated CH4 production, CO2 storage rate and capacity, and of CO2 early-breakthrough and permeability evolution in the reservoir. For the injection pressures selected, CH4 production was enhanced by 2.3%, 14.3%, 28.5%, respectively, over the case where CO2 is not injected. Distinctly different evolutions are noted for permeability in both fractures and matrix due to different dominating mechanisms. Fracture permeability increased by 1/3 for the injection scenarios due to the dominant influence of CH4 de-sorption over CO2 sorption. CO2 sequestration capacity was only of the order of 104 m3 when supercritical for a net recovery of CH4 of 108 m3.
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M3 - Conference contribution
AN - SCOPUS:84927643104
T3 - 48th US Rock Mechanics / Geomechanics Symposium 2014
SP - 1183
EP - 1192
BT - 48th US Rock Mechanics / Geomechanics Symposium 2014
A2 - Petersen, Lee
A2 - Sterling, Ray
A2 - Detournay, Emmanuel
A2 - Pettitt, Will
A2 - Labuz, Joseph F.
PB - American Rock Mechanics Association (ARMA)
T2 - 48th US Rock Mechanics / Geomechanics Symposium 2014: Rock Mechanics Across Length and Time Scales
Y2 - 1 June 2014 through 4 June 2014
ER -