Abstract

The Champion West field was discovered in 1975 and named Champion West in 1990. The field is located in the North of the Brunei Offshore sector.

Phase 3 of this project, is the latest development with 20 wells (oil & gas). These Extended Reach Drilling (ERD) wells, are designed as "snake" wells penetrating the reservoir several times, in order to create multiple drainage points snake well develop oil rim reservoirs. All the wells are of different horizontal lengths, as can be seen in Figure 1 and 2.

The objective of this paper, is to present the learning and best practices gained after drilling 5 of these snake oil wells, during Champion West phase 3a. Best practices refers to those developed during the project, that have resulted in:

  • reduction of costs, by reducing trouble time (Non Productive Time)

  • reduction bit off-bottom circulation times

  • increase of bit on-bottom time

  • improved ability to clean the hole, resulting in trouble-free trips

  • trouble free casing runs

  • the deepest SMART completion in the world

The 350 days campaign was delivered 49 days earlier than planned and below budget. Total cumulative drilling length was of 34 km. This performance allowed the Well Construction team, to achieve the Shell Global EP, Rig of the Fleet award, twice in 3 years.

Introduction

The Champion West structure is 12 km long by 3 km wide, with depths varying between 2,000 - 4,000 m. Reservoir pressures range from 200–600 bar, with a temperature range of 80–120°C. It consists of highly stratified/laminated reservoirs with erratic fluid fill; narrow, elongated fault blocks; and thin oil rims (10–100m) with a high degree of compartmentalisation. There are over 1000 reservoirs in the Champion West area.

Due to the nature of the vertically stacked, structurally dipping reservoirs, it was recognized at an early stage that a fundamental change from the standard well design was required. Due to the high number of stacked reservoirs, the multilateral concept was not an option because of cost and complexity.

Conventional horizontal wells were also considered, however, the concept was not attractive due to the large number of wells required to drain all the key sands.

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