Abstract

Modern Control Systems can provide sophisticated control for unmanned Wellhead platforms and Offshore Oil and Gas production plants. This paper describes design concepts formulated to modernize offshore control in ADMA-OPCO's fields in the U.A.E. These concepts cover the inter-related topics of Wellhead control and safety shutdown, supervisiory control and data acquisition, fire and gas detection and protection and solar system applications. protection and solar system applications

Introduction

Existing control systems on offshore platforms range from basic pneumatic and platforms range from basic pneumatic and hydraulic to simple electronic analog and digital control systems. As some of these units become obsolete and in need Of replacement due to high maintenance costs, unavailability of adequate spares or capacity limitations, certain problems are encountered. These problems relate to the selection of new equipment, scheduling to minimise downtime, phasing, compatibility and ensuring adequate return on investment. Some specific conceptual designs are presented in this paper which overcome these problems as paper which overcome these problems as well as offer many advantages and new features.

A. Control and Safety Shutdown System for unmanned Wellhead Oil and Gas Production Platforms. Production Platforms.

An unmanned wellhead platform may consist of 3, 6 or 9 slots and one test separator. Each slot accommodates a single or dual string producer or a water injection well. producer or a water injection well. Some of these wellhead platforms have a single outgoing sea-line while other platforms have one or more incoming sea-lines and a single outgoing sealine.

Presently the safety shutdown Presently the safety shutdown functions on most unmanned wellhead platforms are implemented using platforms are implemented using conventional pneumatic and hydraulic logic. These systems use numerous pnueumatic and hydraulic components, pnueumatic and hydraulic components, which on average have low meantime between failure ratings (MTBF). Maintenance costs of a system are directly related to the system reliability.

The system reliability is in turn related to the number of components used and their mean time between failures rating (MTBF). The Pneumatic/Hydraulic system also Pneumatic/Hydraulic system also require a large quantity of tubing and joints. This implies significant effort and cost when installing or renewing these systems typically 1000 meters of tubing and 1400 joints for a nine slot tower).

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