Integrated biogeomechanics and geothermo-mechanics: Applications to geological CO2 storage, hydrocarbon recovery, and enhanced geothermal systems

Date

2021-05

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Abstract

The integrated geomechanical process is a novel and resourceful approach that coalesces multidisciplinary scientific fields with geomechanics to provide solutions to complex scientific problems related to energy and the environment. Recently, there is an eagerness in the energy industry to incorporate low-carbon energy solutions, such as the geological CO2 storage (GCS) and the enhanced geothermal systems (EGS), in addition to improved hydrocarbon recovery innovations, to provide diverse and sustainable energy and solutions. Therefore, the efficient development and application of these low-carbon energy solutions require multidisciplinary scientific systems of approach through an integrated geomechanical process. There exists a lack of knowledge on the interaction and changes in the subsurface energy systems at local (micro) and bulk (macro) scales, and their impact on long-term energy production and/or storage in heterogeneous low-permeability formations.

This novel study explored the development of two integrated geomechanical processes: (1.) “biogeomechanics” by integrating geomicrobiology, geology, and geochemistry with geomechanics, and (2.) “geothermo-mechanics” by integrating geology, geochemistry, and geothermic with geomechanics; and their applications to subsurface storage (e.g., GCS) and energy resources development and production (e.g., EGS and hydrocarbon recovery) in heterogeneous low-permeability sedimentary reservoirs. In the integrated biogeomechanics process, rock samples from diverse low-permeability sedimentary sequences (containing artificially-induced and/or pre-existing natural fractures) were treated and cultivated with distinct cultured microbial strains at distinct temperatures, time, and growth conditions. Subsequently, the temporal localized and bulk geomechanical, mineralogical, and microstructural properties of the rock samples impacted by the microbial strains, were measured. Also, further investigations were conducted on how alterations due to the biogeomechanical processes in low-permeability formations could potentially impact the long-term caprock integrity and CO2 storage security, and hydrocarbon recovery. The integrated geothermo-mechanics process involves synthesizing geology and geochemistry with geomechanics to investigate the mechanical stratigraphy of sedimentary sequences with a known geothermal anomaly and the development of hydrothermal fluid pathways. In addition, a core-scale investigation of the post-diagenetic alterations in rocks was conducted, which included the distribution of open-fractures, mineralized veins, and nodules. The implication of this process for the efficient extraction of geothermal energy from a target EGS in sedimentary-hosted geothermal reservoirs, was also assessed.

This study considers the heterogeneity of these target formations and provides valuable insights into how integrated geomechanical processes could provide novel solutions for subsurface storage and energy resource development to potentially enhance caprock integrity and CO2 storage, improve hydrocarbon recovery, and provide an analog for hydraulic stimulation of viable geothermal reservoir targets at higher in-situ temperatures and higher geothermal gradients.


Embargo status: Restricted until 06/2022. To request the author grant access, click on the PDF link to the left.

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Keywords

Biogeomechanics, CO2 Sequestration, Geothermal Energy, Geomechanics

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