Abstract

This paper examines Shell Expro work in simplifying and standardizing its subsea production systems on 10,000 psi, 300° F rated equipment through the use of proven technology and configured 10 meet common interface requirements. A modular 'building block' approach to design was adopted, whereby trees are easily converted from one style to another (oil, water or gas lift) by the addition or removal of bolt-on, pre-engineered packages. Standardisation of associated control systems has also been applied, together with series hook-up of trees for small developments, A common top interface enables vendor interchangeability of tooling. The use of ROV compatible designs for choke and control module change out are expected to provide significant operational cost savings, Common interfaces allow cross haring of tooling systems between projects and potentially other operators, and are the catalyst for vendors to develop rental tooling pools.

Introduction

Subsea developments are now a widely accepted method of field development and the technology can be regarded as mature, rather than still emerging. in recent years, many papers and discussions have taken place on the benefits of standardisation, but no clear direction towards a common goal has emerged. In reality the perceived benefits have not always proved so attractive and standardisation has been accepted less readily than anticipated.

The need to improve projects' viability has lead to a new impetus to gain the forecasted benefits of subsea standardisation, Shell Expro has undertaken an initiative to simplify and standardise the application of subsea technology, not just for current projects in the Northern North Sea, but also for those future projects in the Central North Sea that require an elevated operating envelope of temperature and pressure.

Operation and scale of Mure business needs. In this case, the first steps towards standardisation of subsea equipment were taken in 1992 with a gradual awareness of the cost and effect of imposed 'in-house' company standards, compared I-J industry standards like the emerging API 17 series.

The standardisation initiative aimed to focus, not just on the company's clement and near term subsea projects, but also on the longer term development prospects of the next years, In this period, it was conservatively estimated there would be a need for an additional thirty subsea well Is, with a large proportion operating in the higher envelope of 10,000 psi and 300°F. These prospects were all situated on the UK Continental Shelf however, focus was also maintained on the future requirements of the emerging deepwater province West of Shetland. Care was taken 10 ensure that future business needs were properly stated and m avoid over-optimistic forecasts.

The initiative, whilst firmly focused on future requirements, also had to recognise the learning points emerging from operating existing subsea developments. A realisation of the true costs of installation and operation of a subsea system highlighted that actual purchase COSI of equipment paled into insignificance compared to the 'through-life' operating costs.

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