Analysis of Sustained Casing Annular Pressure in Relation to Stray Gas Assessment

A key identifier for assessing well integrity related to gas migration investigations (GMIs) is Sustained Casing Annular Pressure (SCAP). The issue of SCAP has been addressed by regulation in some areas, however, gaining a detailed understanding of this well integrity attribute is complex. Unlike the standard annular pressure test (SAPT), part of a casing-tubing-packer integrity testing, SCAP applies to annular spaces that may be open to uncemented portions of the drilled wellbore, cement pumped while casing strings were set, and the casing strings themselves. Further, accessing these annular spaces to perform pressure build-up (BU) or fall-off (FO) tests can be challenging. In some cases, retrofits to the wellhead may be required to even perform pressure testing.

Beyond physical challenges, pressure testing methods vary throughout the industry as do quality control methods, analysis methods, and interpretation of results. This lack of consistent practices can make interpretation of SCAP challenging. This presentation will discuss the significance of SCAP, it’s prevalence throughout all oil & gas producing areas, methods used for identification of SCAP, quality control measures, interpretation methods, and existing regulatory criteria. Furthermore, the presentation will include actual examples to allow real-world examples in both the United States and Internationally.