Optimized Recovery Through Continuing Interdisciplinary Cooperation
Authors: Craig F.F. , Willcox P.J. , Ballard J.R. , Nation W.R. 
Published: December 2007

Close cooperation among reservoir engineers, geologists, and members of other disciplines is needed to develop necessary reservoir descriptions for studies of optimum recovery processes. Two examples given are of a model study of a North Sea dry gas reservoir and an oil reservoir in the Gulf of Suez.

Introduction

Our increasing knowledge of recovery processes has been accompanied by a multiplication of choices available to us in the way we operate a reservoir. Fortunately, there have been significant advances in the technological tools available to the reservoir engineer for appraising these choices. However, the use of this technology requires not only greater skill on the part of the engineer, but also a tremendous volume of detailed data. Today's practicing reservoir engineer is dependent on close cooperation with a variety of disciplines-with the geologist for more detailed reservoir descriptions; with the petroleum and production engineer for performance data and special production engineer for performance data and special test results; with the mathematician, chemist, physicist, and chemical engineer for the continual development of his methods; and with the computer scientist for the application of these methods. The way in which the need for this cooperation has increased is evident in the history of the calculation techniques available to the reservoir engineer. The early hand-calculation methods are typified by the zero-dimensional, material-balance calculation. In this calculation, all detailed information was discarded and the reservoir was treated as a simple tank having average characteristics and properties. Waterflooding led to the development of one-dimensional techniques such as the Buckley-Leverett equation. Layering was simulated by methods such as that presented by Stiles. Two features characterize these hand-calculation methods:the reservoir engineer's skill was used in approximating the real reservoir by one of the simple "ideal" systems for which solutions were available, andin the process, detailed geological and performance data were discarded we invariably had more data than we could use.

A revolution in techniques has come with the advent of numerical simulation models. We are now in a situation where the capability of the tools to use reservoir data frequently exceeds the availability of these data. Far from discarding data, the reservoir engineer today finds himself seeking more data, both in quantity and detail, from the geologist, production engineer, and petroleum engineer. Nor is the flow of information simply one way. With the sophisticated simulation tools now available to the reservoir engineer, reservoir structure can be investigated in much greater detail than previously possible, and history matching can lead to a feedback of possible, and history matching can lead to a feedback of geological information to the geologist. The degree of interaction between today's reservoir engineer and geologist can be illustrated with two examples - the Leman gas field in the U.K. North Sea and El Morgan oil field in the Gulf of Suez, Egypt.

Leman Field

The Leman field in the southern North Sea lies 30 miles off the English coast in 100 ft of water. The field contains more than 10 Tcf of gas reserves and is the world's largest producing offshore gas field. The field came on stream in producing offshore gas field. The field came on stream in 1968 and by 1976 had produced 3.0 Tcf of gas, or nearly 30 percent of the reserves. percent of the reserves. JPT

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