Abstract

Leakage is one of the major concerns in a geological carbon sequestration project due to the adverse environmental consequences. The main leakage risk of CO2 through a thick, low permeable cap rock is identified to be along wells, especially in sedimentary basins that have a history of oil and gas exploration and production. To pursue a robust and cost-effective real-time monitoring technology for CO2 leakage risk detection along the wellbore, a permanently downhole deployed coaxial cable casing imaging system is developed and tested for various deformation modes in laboratory in this paper. The casing imager consists of a helically wrapped coaxial cable on the outside of the casing with coaxial cable strain sensors evenly distributed along the cable. A lab-scale prototype of the casing imager was deployed on both PVC sewer pipes and steel pipes for testing on four commonly observed casing deformation modes in the oil field, including axial compression, radial expansion, bending, and ovalization. The coaxial cable strain sensors were pre-stressed and then helically wrapped and attached onto the outer wall of the pipe at a pre-determined angle with high strength epoxy. Multiple LVDTs or strain gauges were used as independent measurement of the pipe actual deformation in comparison to the casing imager measured pipe deformation throughout all the tests. The test results demonstrated the ability of the lab-scale casing imager prototype in real-time monitoring of casing axial compression, radial expansion, bending, and ovalization, which would prove great value in evaluating wellbore integrity and providing early warnings of leakage risk that will contaminate the ground water during CO2 injection. In addition, the low cost and high robustness of the distributed coaxial cable sensors will greatly lower the downhole monitoring cost and increase the system longevity.

Department(s)

Geosciences and Geological and Petroleum Engineering

Publication Status

Available Access

Comments

U.S. Department of Energy, Grant DE-FE0009843

Document Type

Article - Conference proceedings

Document Version

Citation

File Type

text

Language(s)

English

Rights

© 2024 Society of Petroleum Engineers, All rights reserved.

Publication Date

01 Jan 2016

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