Deepwater Completion Designs: A Review of Current Best Practices

Abstract

The advent of deepwater drilling and the increasing number of deepwater discoveries have led the energy industry to develop new completion design philosophies and technologies for challenges that did not exist in the oilfield less than a decade ago. As a result, the numerous deepwater developments and the experience gained have led to new levels of efficiency and reliability in completion design; risk and economics analysis have joined the technology, safety, and environmental aspects in educated decision processes. Two challenges in particular have created opportunities for advancement. First, rig-time costs for operating in deepwater are so high that efficiency and reliability had to be emphasized to minimize nonproductive time during completion installation. The result was the development of special tools and techniques that allow operators to reduce the number of trips in the hole and to accelerate online time on the drill floor. The effort to decrease nonproductive time paralleled a second important objective: increasing the time of field reliability. Because many deepwater wells are subsea, intervention operations and costs are prohibitive; thus, completions must be designed to minimize or eliminate the need for interventions during the life of the well. This objective intensified the need for better equipment designs with respect to longevity, corrosion, and erosion-resistant materials, work rating specifications, and remote monitoring and control equipment. Although some deepwater projects are completed with dry trees from platforms, this article focuses on subsea wells and the major drivers that have differentiated their completion design processes from those of conventional designs. It also compares some of the solutions adopted to address risks and economic issues and discusses how these solutions vary according to corporate design philosophies and local best practices. Examples of design solutions are discussed for various deepwater areas, including the Gulf of Mexico, West Africa, and Southeast Asia. Introduction Most industries in the world today utilize project management processes and tools to help ensure that final goals are achieved on time and within budget. The oil and gas industry does an excellent job of managing topsides construction projects of new fields using project management tools, but still today the well construction part of projects does not generally utilize these tools to their full potential. The projects are often handed over to "operations" to do the well construction phase, where normal operating procedures are used. Our Completions team has found that to deliver major completions projects, wherever in the world, we must manage our business using strong project management principles rather than the "business as usual" operations-style philosophies. By doing this, we can more effectively deliver the right products and services to the field, on time and within the original budget set out. We can assign the right level of resources at the right time and work around issues that always crop up with mature risk management and contingency plans. The following are the key project management principles we use today:Work breakdown structure (WBS)Milestone planning (GANNT charts)Task assignment (RACI charts)Risk management (Quantitative/Probabilistic)Management of change (MOC)Integration management

Failure mode and effects analysis using a fuzzy-TOPSIS method: a case study of subsea control module

“…The FMEA study is performed by developing a risk priority number (RPN) which helps to compare and prioritize issues for necessary correction. In order to calculate the RPN values for each failure mode, three factors of risk namely the severity of impact (S), the likelihood of occurrence (O) and the likelihood of detection (D) should be rated (Ceccarelli, 2009).…”