Abstract

All brown field operators face the challenge to further develop mature fields from existing facilities, whilst ensuring that infill wells continue to add value to their business. Implementation of innovative drilling and completion technology is an important ingredient to achieve this objective. Conductor Sharing Wellhead (CSW™) technology was identified by Brunei Shell Petroleum Company Sdn. Bhd. (BSP) as one of several key enablers for the cost effective development of mature fields offshore Brunei. This technology maximizes the utilization of the remaining existing surface facilities by accommodating two (or more) new wells in one single conductor slot. Additionally, it has been demonstrated that the application of CSW™ technology markedly reduces overall development costs.

The application of CSW™ technology is therefore not restricted to brown field developments only, but it will also allow new field developments to become more attractive. It is demonstrated that CSW™ allow the installation of smaller platforms that can realize the full potential of their big brothers at reduced capital investment, engineering and installation costs.

The first CSW™ system was installed offshore Brunei in December 1998 in Block 14 in the Champion field. This development utilized two of the existing spare 30" conductors to drill and complete three new horizontal wells with one shared well slot remaining for future use. This initial success led to the identification of additional similar applications and an alternative application such as drilling two wells (per slot) from abandoned conductor slots, recovering their conductors and drilling four new wells from the salvaged conductor slots.

The experience gained with CSW™ technology indicates that drilling two wells from one conductor can save USD 1.0 million compared to two conventional wells, whilst better planning and design improvements have reduced the installation times of the CSW™ by some 50 percent.

This paper describes the details of the planning and execution phases during the CSW™ project. We will also discuss lessons learnt during the course of the project, which resulted in significant cost savings, specific design changes and the delivery of a wellhead system that has now been established as a new drilling standard for the development of brown fields and new field developments alike. Close cooperation between field staff and office staff of both the operator and the wellhead supplier were key in realizing a step change in technological and economic opportunities.

Introduction

Brunei Shell Petroleum Company Sdn. Bhd. has been operating offshore of Brunei Darussalam since drilling its first offshore exploration well in 1957. Major offshore developments commenced after the discovery of the prolific Southwest Ampa field and Champion field in 1963 and 1970 respectively1. Numerous smaller fields were developed during the thirty years following. The AMPA and Champion developments still represent the majority of the offshore surface infrastructure (Figure-1) and unused conductor slots have become a scarce resource in these typically mature brown fields.

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