COMPUTER-GENERATED DISPLAYS IN THE STUDY OF A PRODUCING RESERVOIR

Abstract

Since the Barrow Island oil field was discovered in 1964, over 500 production, injection, and water source wells have been drilled through the principal producing reservoir, the Windalia Sand. With the initial interpretation of logs and core data, and the subsequent recording of production/injection rates and pressure measurements, a large volume of disparate but related data has been accumulated-well evaluations, correlation sheets, porosity and saturation data and fluid production/injection histories.

In late 1972, behaviour of the water-flood indicated the need for additional geological analysis of the Windalia Pool and a subsequent production review and re-assessment of the water-flood programme as a control for future production from the reservoir.

Given limited time and a large mass of data to be reworked and re-evaluated, it was evident that detailed analyses would not be possible without the use of some automatic data processing system to produce the many pre-requisite displays. WAPET's Computer Services Division was called in and a set of computer programs was developed for generating a wide range of maps, cross sections, and performance graphs. All of these provide simple but powerful display-definition procedures to give extensive user control over the scope, content and presentation of a display. Specified data items for a group of wells are easily referenced and operated upon mathematically and logically to produce a number of different displays, e.g., an isopach or water cut map, a stratigraphic cross-section, a series of porosity bar charts, or a series of production performance curves or cross-plots.

The programs were used extensively in the two reservoir studies, and proved to be of great assistance. The power, flexibility, and ease of use of the programs allowed the examination of a large volume of data in a short time, resulting in a much more objective analysis than would have been possible using traditional manual techniques of display preparation.