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Development Geology--Emphasis of the Future: What Is It?

Russell B. Lennon

In last year's opening session we were told that the future emphasis of the oil business will be in development geology. Just what is development geology? This paper will define the job by citing examples of some of the tasks it involves.

As the name implies, it starts after the discovery of an oil or gas field with an orderly delineation and development of the field. For faulted structures, it requires the preparation of precise fault maps as well as multiple horizon maps and possible isochore maps to insure structural conformity. Unconformity traps necessitate accurate construction of intersecting planes, while the early development of a depositional or diagenetic model is essential for the exploitation of a stratigraphic field. In all cases, 3-D seismic may be the answer. Fluid contacts are also needed early in the game, and formation pressures or capillary data may be of assistance.

When development is complete and surveillance begins, the development geologist has two added factors in his favor: production data and time. Production data may point to unseen faults, permeability barriers, or undetected structural complexities. And time may permit a complete, unhurried field review which often results in additional reserves.

Planning and initiating supplemental recovery require a detailed understanding of the reservoir plumbing incorporating all available data. Often this is at the stage that reservoir simulation is done, calling for geological input in detail but generalized enough to be handled by the computer.

All this requires a detailed, analytical engineering approach to the science of petroleum geology.

AAPG Search and Discovery Article #91038©1987 AAPG Annual Convention, Los Angeles, California, June 7-10, 1987.