External Casing Patch: A New Approach To Recomplete The Gas Wells With Cemented Completions

Abstract

Abstract In search of increasing gas production in the Sultanate of Oman, PDO's well engineers face challenges during the exploration of unconventional gas reservoirs. The cost-effective development of those deep tight gas reservoirs requires high fraccing pressure and special completion designs. In the last few years, the procedure to address those challenges ended up being completion failures that occurred during and after high pressure frac jobs, forcing operational teams to shut down several highpotential wells for long periods of time. Those inactive gas wells are awaiting effective, remedial solutions or, on the other hand, be recompleted. However, the cemented-completion type of well design implemented by PDO since mid-late 2000's and widely used in most deep gas wells reduces the options to the minimum due to inability to replace existing 4½"x5½" completions. The fit-for-purpose technique selected to minimize the operational and financial impact of having high-risk, unusable gas wells was a ‘external casing patch’. Such initiative opened a window of opportunities to recover the desired gas production and to continue with planned development phase of the field without jeopardizing the integrity of those wells and the surrounded facilities. The implementation and subsequent optimization of this well-known technology will ensure reliability of the further cemented-completion operations and accountability of gas reserves.