摘要:

CO2 sequestration and CO2 enhanced oil recovery (CO2-EOR) are two major processes that can expose the rock to CO2. The behavior of a rock when saturated with CO2 changes over time, affecting both the mechanical and chemical properties of the host rock. CO2 operation involves the injection and pressurization of reservoirs that usually results in changes to the state of in situ stresses that may initiate fractures. This can lead to slippage along pre-existing fracture and fault systems. CO2 storage in tight formations, either for EOR or sequestration purposes, is imperative to contribute to the current energy transition and mitigate climate change. Thus, injection of CO2 may alter the mineralogy, pore structure, mechanics, and other properties and behavior of tight reservoirs, and sometimes may be susceptible to leakage through induced fractures or reactivated faults. Here, we aim to evaluate and reassess studies on CO2 sequestration in tight reservoirs and associated formations. This report focuses on the changes in properties and behavior of tight rocks (shale and tight carbonate rocks) due to CO2 exposure through CO2 sequestration or CO2-EOR. We highlight the most important findings from available studies to date, and we recommend promising areas of research that can advance the knowledge and development of CO2 sequestration in tight formations.

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