Successful Remedial of Collapsed Conductor Pipe With Collision Issue in Offshore Jack Up Operation

Abstract

In 2020-2021, a drilling campaign was planned in Santan Field as further development of the field. Five wells were proposed including Well-31 to drill from a crowded fixed-platform built in 138ft water depth. New slots was fabricated between the existing wells since platform extension or side track was not feasible at the time, resulting dense well spacing on the surface: 1meter form center-to-center and 0.7 meter between wall-to-wall. The 20”, X-56, and 0.625” WT conductor pipe (CP) was driven vertically by diesel hammer with construction barge prior to rig arrival on the platform. When drilling operations commenced, the 17.5 inch drilling BHA was held up during CP cleaning out. The pipe was suspected collapsed as metal cuttings return to surface. According to hammering job history and projection from actual survey, the hypothesis was that the CP was collapsed due to collision with adjacent wells during piling job. A remedial method was established to repair the collapsed CP with the objectives to open the CP to certain diameter without compromising the integrity of the collided well as the pipes were suspected in contact each other. The main risk of interrupting well integrity of producing well are loss of asset and more fundamentally well control event. A modifications was also required on top section by applying hole-enlargement technology and using flush-joint casing to achieve the same casing size on the production section as the original plan. This paper describes the key strategies in safe CP remedial in a unique collision situation. The methods prevent the company from wasting available well slot and from damaging a valuable asset in a risky job situation. From production and field development perspective, the successful remedial was valuable to keep the well delivered as per target.