TY - GEN
T1 - Key complex process couplings and challenges in the effective recovery of deep geothermal energy
AU - Gan, Quan
AU - Fang, Yi
AU - Im, Kyungjae
AU - Elsworth, Derek
N1 - Publisher Copyright:
© 2018 ISRM & SRMEG (Singapore)
PY - 2018
Y1 - 2018
N2 - Despite attempts to engineer viable deep reservoirs for the recovery of thermal energy at high enthalpy and mass flow rates – dating back to the 1970s – this goal has been surprising elusive. The record is replete with failed attempts, examples on life support and some successes. The key difficulties are in (i) accessing the reservoir inexpensively and reliably at depth, (ii) in penetrating sufficiently far through the reservoir, and (iii) in stimulating the reservoir in a controlled manner to transform permeability from microDarcy to higher than milliDarcy levels with broad and uniform fluid sweep and (iv) to create and retain adequate fluid throughput and heat transfer area throughout the project lifetime. We discuss key controls on permeability evolution in such complex systems where thermo-hydro-mechanical-chemical and potentially biological (THMC-B) effects and feedbacks are particularly strong. At short-timescales of relevance, permeability is driven principally by deformations – in turn resulting from changes in total stresses, fluid pressure or thermal and chemical effects. We explain features of reservoir evolution with respect to both stable and unstable deformation, the potential for injection-induced seismicity and its impact on both reservoir performance and in interrogating the evolving state of the reservoir.
AB - Despite attempts to engineer viable deep reservoirs for the recovery of thermal energy at high enthalpy and mass flow rates – dating back to the 1970s – this goal has been surprising elusive. The record is replete with failed attempts, examples on life support and some successes. The key difficulties are in (i) accessing the reservoir inexpensively and reliably at depth, (ii) in penetrating sufficiently far through the reservoir, and (iii) in stimulating the reservoir in a controlled manner to transform permeability from microDarcy to higher than milliDarcy levels with broad and uniform fluid sweep and (iv) to create and retain adequate fluid throughput and heat transfer area throughout the project lifetime. We discuss key controls on permeability evolution in such complex systems where thermo-hydro-mechanical-chemical and potentially biological (THMC-B) effects and feedbacks are particularly strong. At short-timescales of relevance, permeability is driven principally by deformations – in turn resulting from changes in total stresses, fluid pressure or thermal and chemical effects. We explain features of reservoir evolution with respect to both stable and unstable deformation, the potential for injection-induced seismicity and its impact on both reservoir performance and in interrogating the evolving state of the reservoir.
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M3 - Conference contribution
AN - SCOPUS:85064261777
T3 - ISRM International Symposium - 10th Asian Rock Mechanics Symposium, ARMS 2018
BT - ISRM International Symposium - 10th Asian Rock Mechanics Symposium, ARMS 2018
PB - International Society for Rock Mechanics
T2 - 10th Asian Rock Mechanics Symposium, ARMS 2018
Y2 - 29 October 2018 through 3 November 2018
ER -