Broom field commenced production in August 2004. As the first subsea satellite development of Heather field, which has been on production since 1978, significant changes have had to be made to the Heather platform to accommodate the new production. Broom is now producing about 25 Mbopd from three production wells, compared to Heather's 2500 bopd from eight producers.

Broom development costs were kept to a minimum in order to minimise borrowing requirements and reduce financial exposure in case only low-case reserves were realised. This low-cost strategy has meant that post-development production has been less easy to optimise than in more conventional developments. Examples of this are the lack of inter-field fiscal metering, and use of low resolution instrumentation on the Broom manifold. However, the inclusion of a subsea multiphase flowmeter, and downhole gauges, has helped to maximise Broom production by providing information on reservoir connectivity and well lift performance. Actual performance has been close to the Development Plan's P50 expectations.

By contrast Heather production has suffered significantly as a result of the Broom development. Initial plans anticipated that Heather platform process capacity would not be much affected during topsides modifications. However, this has not proved to be the case, and the water injection and gaslift required to sustain production have not been available during much of the modifications' period. Other major factors have been manning restrictions on the platform, the lack of deck space for well intervention during platform topsides modifications, and the requirement to minimise gas flaring during commissioning. These have had the impact of reducing Heather production to about half the pre-Broom era rate, with consequential impact on field economic performance.

This paper describes the impact that the modifications required for Broom field development have had on the Heather field production, and the performance of Broom field in the first year of production. The relative benefits and difficulties created by the use of turnkey contracts for the drilling and subsea elements of the Broom development are compared to a more traditional contract for the brown-field modifications on the Heather platform.

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