Identification of potential CO₂ leakage pathways and mechanisms in oil reservoirs using fault tree analysis

Abstract

Geological storage of CO 2 technologies has become an important and effective way to reduce the greenhouse gas emissions, especially when it is combined with CO 2 enhanced oil recovery (EOR), which can not only trap CO 2 but also enhance oil recovery. However, the risk of CO 2 leakage has always been a prominent issue. In this paper, the mechanisms and pathways of CO 2 leakage during geological storage in oil reservoirs were analyzed using fault tree analysis (FTR). Besides, monitoring technologies were discussed and deployed in a CO 2 EOR demonstration project. The analysis results showed that the sealing failures of oil producer and CO 2 injector wells, like well cement failure and casing failure, are the main reasons for the CO 2 leakage, which has been observed in the oil field monitoring project. The monitoring results indicated that there is no large-scale CO 2 leakage, while relatively high and abnormal CO 2 concentration in soil gas near some wellbores are observed, which indicates there is some leakage of CO 2 through incomplete cement ring and well casing string. FTR results provide guidelines for monitoring and preventing of CO 2 leakage during geological storage in oil reservoirs. The near-surface monitoring methods, especially the soil gas monitoring technologies, can effectively detect the leakage of CO 2 , and are a proper method for CO 2 leakage monitoring. C 2020

Numerical Assessments of Key Aspects Influencing Supercritical CO2 Foam Performances when Using CO2-Soluble Surfactants

“…84 CO 2 foam has demonstrated significant potential not only on CO 2 utilization but also on CO 2 storage. 85,86 Therefore, the learnings here from enhanced oil recovery could be readily applied to carbon sequestration to benefit both revenue generation and climate control.…”

“…The works here aim to establish a methodology to provide the guidance for the potential surfactant tailoring process and corresponding experimental design during surfactant screening and synthesis, which makes it less time consuming and more cost efficient . CO 2 foam has demonstrated significant potential not only on CO 2 utilization but also on CO 2 storage. , Therefore, the learnings here from enhanced oil recovery could be readily applied to carbon sequestration to benefit both revenue generation and climate control.…”

Comprehensive Review of Sealant Materials for Leakage Remediation Technology in Geological CO2 Capture and Storage Process

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“…CO 2 leakage through geological and engineering pathways. Reproduced with permission from ref . Copyright 2020, John Wiley and Sons.…”

Experimental Evaluation of Combined Plugging System for CO2-Improved Oil Recovery and Storage

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