Geochemical Implications of CO2 Leakage Associated with Geologic Storage: A Review

Abstract

Leakage from deep storage reservoirs is a major risk factor associated with geologic sequestration of carbon dioxide (CO 2 ). Different scientific theories exist concerning the potential implications of such leakage for near-surface environments. The authors of this report reviewed the current literature on how CO 2 leakage (from storage reservoirs) would likely impact the geochemistry of near surface environments such as potable water aquifers and the vadose zone.Experimental and modeling studies highlighted the potential for both beneficial (e.g., CO 2 re-sequestration or contaminant immobilization) and deleterious (e.g., contaminant mobilization) consequences of CO 2 intrusion in these systems. Current knowledge gaps, including the role of CO 2 -induced changes in redox conditions, the influence of CO 2 influx rate, gas composition, organic matter content and microorganisms are discussed in terms of their potential influence on pertinent geochemical processes and the potential for beneficial or deleterious outcomes.Geochemical modeling was used to systematically highlight why closing these knowledge gaps are pivotal. A framework for studying and assessing consequences associated with each factor is also presented in Section 5.6. v

Development and evaluation of the coaxial cable casing imager: a cost‐effective solution to real‐time downhole monitoring for CO2 sequestration wellbore integrity

“…19 for four ovalities ( Table 3). The representative curve is acquired based on the three LVDT measurements and Eqn (5). Compared to the representative curve, the sensor measurements distribute evenly on two sides of the curve, but the magnitude is much smaller, which means the system is not very responsive to the deformation.…”

“…CO 2 leakage‐induced problems such as groundwater contamination, plant stress, and biomass changes are the primary concerns in a geological carbon sequestration project . Each CO 2 sequestration project will have its unique leakage risk assessment, but in sedimentary basins that have a history of oil and gas exploration and production, the main leakage risk is commonly identified to be along existing wells .…”

“…C O 2 leakage-induced problems such as groundwater contamination, plant stress, and biomass changes are the primary concerns in a geological carbon sequestration project. [1][2][3][4][5] Each CO 2 sequestration project will have its unique leakage risk assessment, but in sedimentary basins that have a history of oil and gas exploration and production, the main leakage risk is commonly identified to be along existing wells. [6][7][8][9] Since the cement sheath is one of the primary barriers to prevent wellbore leakage and failure, and since what happens during the cementing operation and thereafter can greatly affect the long term wellbore integrity, 10 it is of great importance to monitor the downhole activities during the cementing and CO 2 injection process to provide early warnings of wellbore leakage.…”

A numerical study on the feasibility of evaluating CO2injection wellbore integrity through casing deformation monitoring

“…E valuating and maintaining wellbore integrity is crucially significant throughout the whole process of CO 2 sequestration due to the hazardous environmental impact caused by CO 2 leakage. [1][2][3][4][5] Wellbore leakage is a reoccurring problem for cased wells, 6,7 and it is difficult to conduct effective remediation jobs to fix the problem. 8 Thus, monitoring wellbore integrity is especially important to ensure the successful implementation of a CO 2 sequestration project.…”

Recent developments and perspectives on the treatment of industrial wastes by mineral carbonation — a review

“…The first method of CCS was that of geological sequestration, which came to be used on a large scale around the 1970s in the extractive industry for enhanced oil and gas recovery [6]. While plenty of capacity may exist for this type of storage [7], there are important concerns over leakage risks and longterm stewardship of the stored CO 2 [8,9]. An alternative for CO 2 sequestration involves CO 2 injection in oceans, preferably at great depths where this gas reacts with water to form carbonic acid.…”