Cementing Under Pressure in Well-Kill Operations: A Case History From the Eastern Mediterranean Sea

Abstract

Summary Well control can be an unpleasant experience. In its initial stages the problem often appears unconquerable and weeks can pass without progress. This paper is about the successful abandonment of such an episode of well control, in deepwater (i.e. greater than 300 m water depth), that was initially suspended with a closed-in subsea BOP. The BOP held in place a sheared 5-in. drillpipe that had been intermittently blowing dry gas and formation cuttings to the rig floor for 20 days. The objective of the well-recovery operations was to re-enter the well and properly abandon it without creating another uncontrolled situation. All operations were to be conducted in compliance with HSE protocols. It was paramount to have total control of the well at all times necessitating two BOP stacks. This contingency resulted in the suspension of a heavy load on the seabed, subject to excessive bending moments during bad weather. The well head arrangement was essential but the time loss caused by weather conditions was becoming intolerable. New and innovative plans made during the well-control operations cut 3 to 4 weeks of uninterrupted operation down to 5 days of operation. Cementing under pressure was the key abandoning solution. Several scenarios were drawn up for this eventuality and this paper elaborates on the decisions, choices, and solutions made during the final abandonment operation.