Abstract
Sustained casing pressure (SCP) is a common problem throughout the oil and gas industry. Many wells will suffer from the problem at some point during their lifetime(Rocha-Valadez et al., 2014). Currently, there are several methods available to remediate SCP. However, there are several factors that determine the remediation approach. These can include but are not limited to the source of the pressure, the location of the pressure i.e. which annulus or combination of annulus, the well construction design, the life cycle stage of the well, the barriers in place and the companies/regulatory policies etc. Whilst not all SCP issues are the result of leaks in casing, liners or the cement that had has been used to provide zonal isolation, this paper is primarily focused on these types of issues.
The primary objective of cementing is to provide zonal isolation, such that downhole fluids are prevented from flowing into the casing annuli and potentially to the surface. The exception being for the production flow path. Such isolation is part of well integrity (NORSOK, 2004). Any event/incident that damages the sealability of cement or causes downhole fluids to flow to the surface behind casing strings jeopardizes the integrity of the well. These events lead to SCP and may require a shut-in of the well if not cured. The objective of this paper is to discuss yard tests of Bismuth alloy as a treatment for SCP. The Bismuth alloy will be a gas tight sealant at the fluid leakage source location.
