Sustained casing pressure (SCP) is a well-known industry issue in US unconventional resource plays. It is defined as a sustainable buildup of pressure at the wellhead in any annular region of a well. From a remediation standpoint, the tools, materials, and technologies needed to locate and resolve already occurring SCP are insufficiently developed. There are no proven methods to locate and access a flow path in an annulus behind pipe and restore seal integrity. This is particularly important in the Fayetteville Shale, where current well architecture limits remediation of annular flow channels to perforation squeeze operations that require the location of the pathway be known for successful application. As part of a government funded study, development is underway to develop methods and materials for remediation of SCP in shale wells, focusing primarily on the Fayetteville Shale. Presented here are the results of testing done to provide conceptual proof for two methods and tools in development to locate flow paths behind casing.

This paper encompasses the development and testing of a downhole tool and corresponding algorithms that will be used to detect flow behind casing. This will include lab scale testing results for a software package developed for a standard noise log tool as well as the results from proof of concept and subsequent component testing for a more sophisticated pulse style acoustic tool currently in development.

While the technologies developed for this project are designed to aid in annular flow path detection and subsequently the remediation of horizontal wells drilled in the Fayetteville Shale, the materials and methods determined by this study could benefit many other shale fields in development as well as any other fields where annular flow path detection is required.

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