Geomechanics Contribution to CO2 Storage Containment and Trapping Mechanisms in Tight Sandstone Complexes: A Case Study on Mae Moh Basin

TL;DR

This study demonstrates that reservoir geomechanics significantly influence CO2 storage security and trapping mechanisms in tight sandstone formations, emphasizing the importance of including geomechanical factors in storage assessments.

Contribution

It provides a detailed case study showing how reservoir geomechanics affect CO2 containment and trapping, which has been previously underappreciated in modeling.

Findings

Reservoir pressure increased to 80% of fracture pressure when geomechanics was considered.

Geomechanics reduced CO2 plume migration and leakage risk.

Higher reservoir pressure enhanced residual and solubility trapping mechanisms.

Abstract

Recognized as a not-an-option approach to mitigate the climate crisis, carbon dioxide capture and storage (CCS) has a potential as much as gigaton of CO2 to sequestrate permanently and securely. Recent attention has been paid to store highly concentrated point-source CO2 into saline formation, of which Thailand considers one onshore case in the north located in Lampang, the Mae Moh coal-fired power plant matched with its own coal mine of Mae Moh Basin. The current study is thus aimed to examine the influence of reservoir geomechanics on CO2 storage containment and trapping mechanisms, with co-contributions from geochemistry and reservoir heterogeneity, using reservoir simulator, CMG-GEM. With the injection rate designed for 30-year injection, reservoir pressure build-ups were 77% of fracture pressure but increased to 80% when geomechanics excluded. Such pressure responses imply that storage security is associated with the geomechanics. Dominated by viscous force, CO2 plume migrated more laterally while geomechanics clearly contributed to lesser migration due to reservoir rock strength constraint. Reservoir geomechanics contributed to less plume traveling into more constrained spaces while leakage was secured, highlighting a significant and neglected influence of geomechanical factor. Spatiotemporal development of CO2 plume also confirms the geomechanics-dominant storage containment. Reservoir geomechanics as attributed to its respective reservoir fluid pressure controls development of trapping mechanisms, especially into residual and solubility traps. More secured storage containment after the injection was found with higher pressure, while less development into solubility trap was observed with lower pressure.