THE POTENTIAL OF THE GLOBAL POSITIONING SYSTEM (GPS) IN PETROLEUM EXPLORATION

Abstract

The exploitation of offshore hydrocarbon reserves needs consistent high accuracy positioning in many applications throughout all operational stages from exploration to development and subsequent field maintenance.

Traditionally, this requirement has been met by a variety of terrestrial electronic position-fixing aids all of which have advantages and disadvantages in relation to different offshore tasks. Now satellite systems are being developed which will have a major impact on offshore positioning and the most important of these is the American NavStar Global Positioning System (GPS).

In GPS the marine navigator and surveyor at last has a system that potentially can give him a truly global 24-hour real-time high-accuracy system which will meet or assist with many of his requirements for positioning.

However, great care must be exercised in the use of this military system over which the civil user has no direct control. In addition, errors in the system, some inherent and some deliberately applied, must be monitored and if possible corrected. Consequently, significant civil user infrastructure must surround the application of GPS for offshore work in order to achieve the high-quality accurate service demanded.

This paper discusses the current and future performance of GPS and looks at the sources of error, with particular attention to the deliberately applied Selective Availability, arguing the need for a robust, monitored, differential environment, but noting the problems of providing a dependable data link.