Assessing The Operational Efficiency of Deep Water Production Systems
Authors: White Charles N. , Kelly Bill , Stevens Jim , Rowe Steve , Brendling Bill 
Published: October 2008

Probabilistic methods have been applied to assess operations and operating costs (OPEX) for a number of deep water field developments. The studies have attempted to define operating different between 'dry tree' and 'wet tree' production scenarios in ways that allow comprehensive cornmercial evaluations on Norway's challenging deep water frontier. A key part of the work involved the generation of means to calculate the relative operating efficiency of competing development approaches so that the 'cost-of lost (or delayed) production can be properly accounted. A computational simulation tool has been established and applied to capture the critical component and operational activities required to bring oil from the reservoir to market. This is a very general flexible simulation ?engine' that can model and analyze differences between any of the many different 'flavors' of possible development scenarios. It can be used to evaluate the economic impact of differing development approaches or just differing operating strategies for a given development scenario. It can be applied for systems in any water depth, but in very deep waters, it is obvious that many aspects of well servicing can be strongly affected and deserve special attention.

The present work has assessed operational advantages or disadvantages for 'wet tree' and 'dry tree' scenarios in a very harsh deep water environment. Software development, careful modelling, and analysis have produced results that characterize critical performance issues for these competing senarios under a range of conditions and. Some key results and clarifications of their meanings for deep waterproduction system selection are presented.

Introduction

Deep water frontiers are gaining the focus of many major oil companies. The serious played understand that exploration and production (E&P) is a risky business where awareness of the uncertainties and assessing their economic influences is important. This is especially true when stepping into such challenging frontiers as west of the Shetlands (UK) and bNorway's basin; where managing the investment and reservoir performance risks tends to dominate over traditional decision-making approaches. Field development opportunities in these very deep waters and harsh environments demand highly productive reservoir and efficient production systems. The high casts of well operations and production and drilling facilities are exacerbated by the great depths and exposure to complex and dangerous metocean conditions. Serious efforts to reduce the cost of deep water developments are being vigorously pursued by many operators. However, it takes a balanced, mature appraisal of the uncertainties and risks involved when considering front-end cost savings that may have detrimental consequences on immediate and long term revenue streams in such challenging environments.

Much has been written about the probabilistic approaches to estimating capital investment (CAPEX) risks. This paper addresses a mains for and the uncertainties involved in estimating the performance of production and export systems as they affect the revenue stream an operator hopes to realize from an offshore field development.