Pull Your BOP Stack - Or Not? Systematic Method to Making This Multimillion Dollar Decision

Abstract

This article, written by Senior Technology Editor Dennis Denney, contains highlights of paper SPE 119762, "Pull Your BOP Stack - Or Not? A Systematic Method to Making This Multimillion- Dollar Decision," by Jeff Sattler, SPE, WEST Engineering Services, prepared for the 2009 SPE/IADC Drilling Conference and Exhibition, Amsterdam, 17-19 March. The paper has not been peer reviewed. Pulling the blowout-preventer (BOP) stack, particularly in deep water, is costly. While in most cases this action is proper, circumstances arise when the stack pull could be avoided. Case studies are presented in which planned stack pulls were circumvented or could have been. A systematic protocol can be developed before starting a well to define the decision-making process for stack pulls. Introduction Current deepwater-rig downtime costs approach USD 1,000,000/D. Pulling a BOP stack, particularly in deep water, is financially significant. This action is necessary most of the time. However, on occasions when the stack pull could be avoided, all parties to this action rightfully question how to take advantage of the unfortunate learning situation. Avoidable stack pulls occur for a variety of reasons, including: Inadequate information about the situation or equipment Inadequate staff training Unclear understanding of regulatory requirements Unclear understanding of company requirements Lack of access to experts who could assist in the decision The full-length paper details a systematic protocol to use before starting a well or during the drilling, if necessary, to help define the decision-making process for stack pulls for a specific program. Once a problem develops, the root cause should be identified, if possible, and necessary steps taken to analyze the situation and decide if drilling can continue safely. Often, this part of the process requires the advice and experience of one or more experienced drilling experts from within or outside the parties directly involved in the drilling operation. Predrilling Planning To help ensure a good decision when an abnormal BOP event occurs, preparations should be made before drilling starts. While several items presented here require time to investigate or review, often this process is not engaged because much of the information is considered to be intuitive. However, after drilling begins and because time is expensive (up to USD 700/min or more), the time required to analyze a situation fully is sometimes not allocated. Predrilling planning, as shown in Fig. 1 of the full-length paper, should include the following items. Assess Staff Training. Review staff experience and training to determine if additional training before drilling could reduce the risk of downtime. For example, does the subsea engineer need to be educated on the functionality of a revised circuit or control component? Would the subsea engineer benefit from a refresher on the latest variable-bore-ram capabilities and limitations?