Abstract
The paper discusses a cost-effective approach involving the implementation of a high-resolution detecting technology to identify a micro-tubing leak and further remediation by applying a method of injecting a pressure activated sealant to eliminate the leak.
Well A in field Kashagan was completed using 5 ½″ in single-string cased hole completion intersecting carbonate zones. It produced up to 20,000 BPD (3180 M3/D) on self-drive starting from March 2017. The reservoir pressure is up to 780 bar (11,300 psi) and well fluid composition is with 16% H2S and 5% CO2 mol.
In July 2018, an increase in A-annulus pressure up to 3.6 bar/day was observed. The diagnosis suggested an issue with a downhole tubing section above the production packer indicating a need to identify the leak point and remediate the leak to bring the well online.
A detailed analysis of various techniques for bringing the well in production was conducted keeping in mind the associated cost and time for each method. After performing a detailed technical and economic analysis, the decision was made to perform the operation in two stages. The first stage is to identify the micro-leak with high resolution spectral noise logging tool, while the second stage is to rectify the leak with straddle pack or pressure activated sealant.
This operation is also considered to be a proactive approach in reducing emissions, as it limits the emission sources, and those parameters controlling the individual emissions; and finally obtaining knowledge of the economic impact. The operation in well A was successfully executed and the well integrity was regained allowing bringing the well back online in shortest time (minimal as compared to the workover operations, far safer and more cost-effective).
