RAM Analysis for Deepwater Subsea Developments
Authors: Brandt Håvard , Eriksen Remi 
Published: October 2008

Field development profitability is a function of many income and expense factors such as capital expenditures (CAPEX), operating expenditures (OPEX), production rate, product price and the frequency of component failures. Component failures reduce the field total production rate and increase OPEX. Regardless of the chosen concept, the ability to efficiently keep production wells on stream is one of the most important factors determining field economic performance.

When moving into deeper water, subsea interventions become more expensive and are associated with longer waiting times for the required intervention vessels. Furthermore, deepwater developments rely on new technology, which has yet to be field proven. This paper demonstrates how Reliability, Availability and Maintainability (RAM) analysis can be used to quantify the costs associated with well interventions and subsea repairs. These costs can be combined with estimates of CAPEX and OPEX to select efficient subsea deepwater solutions from a total lifecycle cost perspective.

Until recently deepwater ventures were evaluated based on the balance between potential revenue, (CAPEX) and operational expenditures (OPEX). Little effort was put into evaluating the potential of lost revenue and expensive intervention costs due to component failures. RAM Analysis is a systematic approach to evaluate the uncertainty related to these "unforeseen" events, and can strengthen the decision making process.

This paper describes the RAM analysis methodology, and illustrates some of the benefits of applying it. Furthermore, an overview of industry initiatives currently carried out by the deepwater industry to develop and to qualify new technology is given

Introduction:

During the last forty years technology has been essential to provide access to hydrocarbon resources increasingly difficult to reach and produce. The economical efficiency of these new achievements was never questioned as long as margins were high and the demand was growing. Over the last decades however, finding and producing quickly was no longer the only objective, companies were forced to cut costs and produce and explore more efficiently.

Today, access to the resources and cost reduction are combined efforts in the industry, and remarkable improvements have been made within different disciplines in order to meet the demand for faster and more cost efficient exploration and production. Within the field of drilling technology for example, mastering horizontal drilling has allowed for more complex well architecture, which has reduced the required number of wells and improved productivity. The latest achievement in this area, is the development of intelligent well completions allowing for predrilled wells with access to several zones, which reduce later costs associated with re-completion of the reservoir.

Technological improvements have allowed oil and gas developments to emerge into deep and ultra-deep waters, introducing an operating environment not encountered in shallow water. Following this trend, it is essential to understand the various uncertainties associated with operation in these new environments, and accept full accountability for the economical consequences. The current deep and ultra-deep water developments in the Gulf of Mexico are forcing operators and manufacturers to look for new cost efficient solutions without compromising safety, property or the environmental issues.