A Brownfield Well Re-Design with Casing While Drilling

Abstract Developments with high depletion tend to have many drilling problems where young shales need to be drilled and losses are incurred. In order to avoid spending large amounts of time and money curing losses, a complete re-design has been carried out in a field in the North of the Sultanate of Oman. The casing scheme for the wells has been successfully reduced from four to two casings, making use of a hydraulic single joint rig. Furthermore, casing while drilling with stage cementing tools has been trialed, whereby the stage tools are drilled out with the casing while drilling bit. Many lessons have been learned as described in this paper.