ABSTRACT: South Dome Oregon Basin Field: An Integrated Study for Improved Oil Recovery Opportunities

Michael J. Heymans, David R. Petro, A. J. Kaltenback, R. M. Just

Through the combined efforts of geoscientists and engineers to characterize the Tensleep and Phosphoria reservoirs, improved oil

recovery opportunities have been realized in the South dome of the Oregon basin field. This giant multi-producing-horizon field began production in 1928 and is located approximately 12 mi southeast of Cody, Wyoming. Integrated reservoir characterization results in this field generally are also applicable to other Tensleep and Phosphoria reservoirs in the Big Horn basin.

Methods used to characterize these reservoirs include (1) a computer database and state-of-the-art computer mapping techniques to manipulate and interpret geologic and well-performance data; (2) stratigraphic paleoreconstructions for flow zone and matrix properties delineation; (3) build-up and fall-off tests for fracture properties delineation; (4) crude oil geochemistry analyses to confirm that both reservoirs were part of a common hydrodynamic system and, therefore, should have a common free-energy surface for estimating original oil in place; and (5) production geophysics for high-angle fault delineation.

All of these methods have been incorporated into a full-field, 281-well, computer numerical simulation in an attempt to match the history of reservoir performance from initial production in 1928 to the present. A match of oil and water production and reservoir pressures will be used to predict future reservoir performance. This study should provide the basis for optimum reservoir management and potential enhanced oil recovery projects during the remaining life of this field.

AAPG Search and Discovery Article #91003©1990 AAPG Annual Convention, San Francisco, California, June 3-6, 1990