ABSTRACT

System standardisation is acknowledged to be one area which can significantly reduce the life cycle costs for any project This paper looks at subsea control systems, specifically the Norsk Hydro Troll Olje Project in the light of previously defined objectives

INTRODUCTION

The subject of standardisation for subsea control systems has been broached several times This review takes as its starting point the paper presented at Subsea Control and Data Acquisition (1992) otled "Standardisation of Subsea Control Systems" Since that time, the first deliveries to the Troll Olje project have taken place and we are in a position to evaluate some of the theories and practicalities in the light of a "real life" project

The alternatives of a "Company Standard" or "Vendor Standard" both have drawbacks, however the use of commercially available products which have been pre-qualified seems to be a path that several vendors and oil companies might like to consider

Since the system suppliers are in continual competition in the world market, the prices should be market driven and a monopoly situation is less likely to occur. The "market" is governed by oil companies and they have different views and requirements which may make standardisation more difficult to achieve

We will show the areas where "standardisation" is reasonably easy to achieve and look at the more difficult topics such as the Subsea Electronic Module (SEM) where the challenge is greater

The Starting Point for Standardisation

In late 1991, Norsk Hydro started presenting their views to various subsea control vendors with the intention of having some "standardisation" in place when the Troll Olje subsea control package came out for tender

There were some general function requirements and some specific equipment requirements :-

  • an electrohydraulic system was desirable,

  • subsea communication would be superimposed on the power cables;

  • it would be possible to modify subsea software from topside,

  • subsea software was to be written in a high level language,

  • Subsea Control Unit (SCU) would be an integral part of the DISCOS (Distributed Supervision, Control and Safety) system,

  • Hydraulic Power Unit (HPU) would be part of the normal topside equipment,

  • Emergency Shutdown (ESD) would be obtained by means of a system physically separated and different from the Process Shutdown (PSD) system,

  • Xmas tree Instrumentation would not influence the workover frequency,

  • Interfaces should be standardised and resolved by the various subcontractors

With these requirements as a base, and a range of pre-qualified components, the subsea control vendors were asked to quote against a well tried solution using "standard" components

Norsk Hydro had all the experience of TOG1 and previous projects to hand when reviewing the various solutions and components, and were able to ensure that known pitfalls were avoided The GEC-Marconi Oil & Gas (G-MOG) solution was to fit the pre-qualified components into an existing and tried solution which has evolved over many projects

"A move towards subsea control system standardisation?" This is the question we will now attempt to answer

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