Prediction of methane leakage through primary cement barrier in the High Island, OPD, Gulf of Mexico

Authors: Wise, Jarrett; KARAMI, HAMIDREZA - University Of Oklahoma; CORINA, ANISA - Norwegian University Of Science And Technology; OPEDAL, NILS - Sintef - Applied Research, Technology And Innovation; VRÅLSTAD, TORBJØRN - Sintef - Applied Research, Technology And Innovation; SANGELSLAND, SIGBJØRN - Norwegian University Of Science And Technology; NYGAARD, RUNAR - University Of Oklahoma

Submitted to: Journal of Natural Gas Science and Engineering
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/6/2022
Publication Date: 3/9/2022
Citation: Wise, J., Karami, H., Corina, A.N., Opedal, N., Vrålstad, T., Sangelsland, S., Nygaard, R. 2022. Prediction of methane leakage through primary cement barrier in the High Island, OPD, Gulf of Mexico. Journal of Natural Gas Science and Engineering. 101. Article 104511. https://doi.org/10.1016/j.jngse.2022.104511.
DOI: https://doi.org/10.1016/j.jngse.2022.104511

Interpretive Summary: Oil and gas wells leak resulting in greenhouse gasses being released into the atmosphere. The leakage path is within the cement used when constructing the well. Methods to predict the amount of leakage coming from the well have been tried. The issue with the previous research is scientists assumed water was the leaking fluid versus a gas (e.g. methane). This manuscript presents gas flow mathematical equations to improve the accuracy of prediction methods. The developed work is used in conjunction with a model that predicts the fracture volume and compares the leakage rates using the new method with the previous method assuming water. The previously used method underpredicts the amount of gas leakage that could be released from an old oil and gas well. These results are expected to be used by companies and/or regulatory agencies to develop guidance for mitigating climate change due to leaking oil and gas wells.

Technical Abstract: With the increasing concern of greenhouse gases emitted from oil and gas wells, wellbore leakage has been a topic of interest lately. Previous research has shown that the annular cement used to complete the well and is a primary barrier of fluid migration can experience debonding to the casing causing a microannulus. The microannulus can propagate up the cement sheath to the top of cement depth causing a continuous leakage pathway. Previous methods quantify the corresponding leakage using laminar Hagen-Poiseuille flow assuming an incompressible fluid. That methodology is valid assuming water or oil as the leaking fluid but is voided for gas leakage. Therefore, an analytical laminar gas flow model including the effect of gravity was developed. The objective of this work is to investigate the difference between using Hagen-Poiseuille flow for analyzing gas flow data versus the developed gas flow model. The gas flow model is verified with experimental data and the potential leakage of a previously studied Gulf of Mexico well is compared using the different models. The results show that analyzing gas leakage with Hagen-Poiseuille flow underestimate leakage rates when compared to the developed gas flow model.