Safe and effective storage of CO2 and compliance with regulatory protocols requires an understanding of existing wellbores that could be potential leakage pathways. Wellbore integrity is a key risk factor for carbon capture and storage (CCS) applications. Wells (existing and new) may present risks for CO2 geologic storage, including wells which underwent poor cementing and plugging processes, or had incomplete records. This project will help address these risks through completion of a systematic assessment of wellbore integrity using regulatory and industry information/data.
The project will determine the distribution of wellbores in a study area that includes the Appalachian and Michigan Basins, with a more detailed focus on northeastern Ohio and neighboring areas of Pennsylvania and southern Michigan (Figure 1). The project team will compile and sort all pertinent data obtained from state or industry databases for the large number of wells in the study area. These data will be reviewed, categorized, and statistically analyzed using factors such as well age, geologic setting (including potential exposure to CO2, especially in some shale gas wells), construction materials, test and operation data, and well remediation history. Screening criteria will be used to develop a short-list of oil/gas, gas storage, or injection wells for a detailed assessment of well history and to collect sustained casing pressure and mechanical integrity test data. The combined data will be used to evaluate the risk of well failure with regard to meeting injection regulations, development of remediation plans, and financial impact on projects.
The overall goal of the Department of Energy’s (DOE) Carbon Storage Program is to develop and advance technologies that will significantly improve the effectiveness of geologic carbon storage, reduce the cost of implementation, and prepare for widespread commercial deployment between 2020 and 2030. Research conducted to develop these technologies will ensure safe and permanent storage of carbon dioxide (CO2) to reduce greenhouse gas (GHG) emissions without adversely affecting energy use or hindering economic growth.
Geologic carbon storage involves the injection of CO2 into underground formations that have the ability to securely contain the CO2 permanently. Technologies being developed for geologic carbon storage are focused on five storage types: oil and gas reservoirs, saline formations, unmineable coal seams, basalts, and organic-rich shales. Technologies being developed will work towards meeting carbon storage programmatic goals of (1) estimating CO2 storage capacity +/- 30 percent in geologic formations; (2) ensuring 99 percent storage permanence; (3) improving efficiency of storage operations; and (4) developing Best Practices Manuals. These technologies will lead to future CO2 management for coal-based electric power generating facilities and other industrial CO2 emitters by enabling the storage and utilization of CO2 in all storage types.
The DOE Carbon Storage Program encompasses five Technology Areas: (1) Geologic Storage and Simulation and Risk Assessment (GSRA), (2) Monitoring, Verification, Accounting (MVA) and Assessment, (3) CO2 Use and Re-Use, (4) Regional Carbon Sequestration Partnerships (RCSP), and (5) Focus Area for Sequestration Science. The first three Technology Areas comprise the Core Research and Development (R&D) that includes studies ranging from applied laboratory to pilot-scale research focused on developing new technologies and systems for GHG mitigation through carbon storage. This project is part of the Core R&D GSRA Technology Area and works to develop technologies and simulation tools to ensure secure geologic storage of CO2. It is critical that these technologies are available to aid in characterizing geologic formations before CO2-injection takes place in order to predict the CO2 storage resource and develop CO2 injection techniques that achieve optimal use of the pore space in the reservoir and avoid fracturing the confining zone (caprock). The program’s R&D strategy includes adapting and applying existing technologies that can be utilized in the next five years, while concurrently developing innovative and advanced technologies that will be deployed in the decade beyond. For this project, researchers will provide insight into well integrity in potential carbon storage settings to help ensure safe and effective CO2 storage.
The project is making a vital contribution to the scientific, technical, and institutional knowledge base needed to establish frameworks for the development of commercial-scale CCS. The proposed project will be one of the first attempts to address risk factors associated with well integrity in an area with significant CO2 emissions and a large number of preexisting boreholes from more than a century of oil and gas activity. Detailed evaluation of well records from oil/gas wells, gas storage, and brine injection wells will help to assess of the impact of these boreholes on CO2 storage and develop a model to address key technical, regulatory, and stakeholder issues for CCS deployment.
The presence of pre-existing wellbores and plugged boreholes is viewed as one of the most important risk factors for CO2 containment. The Carbon Storage Division’s programmatic goal of ensuring 99 percent storage permanence will be supported by this effort to ensure efficient storage or utilization of CO2, and mitigate its potential release.
The objectives of this project are to determine the distribution of active and plugged wellbores in the study area through collection and analysis of well records, evaluation of annulus pressure from Underground Injection Control (UIC) Class II injection/production wells and/or gas storage wells, and analysis of well integrity in relation to CO2 storage targets; evaluate regulatory, field deployment, and commercial implications of the well failure risk profiles at selected sites for CO2 storage or utilization. The project includes systematic review of well records to determine categories of well integrity in a real-world field setting. The data review will be linked to analysis of field records on well annulus/casing pressure as they relate to well condition. The specific objectives of this project will be achieved through a combined research and analysis effort that includes:
Determining the distribution of wellbores in the study area through collection and analysis of well records, evaluation of annulus pressure from U.S. Environmental Protection Agency regulated Class II injection wells and/or gas storage wells as analogues for CO2 storage wells, and analysis of well integrity in relation to CO2 storage targets.
A systematic review of well records to determine categories of well integrity. The data review will be linked to analyses of field records on well annulus/casing pressure related to potential well integrity issues.
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