Abstract: An Interdisciplinary Approach to Reservoir Management: The Malu Field, West Niger Delta, Nigeria

B. A. Patterson, C. T. Bluhm, E. U. Adokpaye, F. M. Kpenkaan, B. A. Onasanya

The Malu Field is 175 kilometers southeast of Lagos, offshore Nigeria. The field was discovered in 1967 and brought on stream in 1971. Peak production reached 31,300 barrels per day in 1972. Twenty-six wells have been drilled in the thirty-six square kilometer size field. In 1990 original-oil-in-place was estimated at 345 million barrels with cumulative production of 109 million barrels and an estimated 40 million barrels of remaining reserves.

The Malu Field review was initiated in 1994 to resolve structural and production inconsistencies and therefore improve reservoir performance. The tools used include reprocessed three-dimensional seismic, oil chemistry (primarily gas chromatography), and production data.

The complexly faulted field is subdivided into seven different fault blocks. Growth faults generally trend northwest to southeast and are downthrown to the west. Twenty-five different hydrocarbon-bearing sands have been identified within the field. These sands are separated into sixty-three different reservoirs by the series of southeast trending growth faults.

Most sands are laterally continuous within mapped fault blocks except in east Malu. Cross-fault communication of oils occurs among several of the shallow reservoirs in west Malu allowing wells to deplete unintended horizons. In addition, three of the dual string completions are producing oil only from only the upper sands.

The integration of seismic, oil chemistry, and production data allows more efficient management of production by providing accurate structure maps, reserve estimates, drainage pathways, and justification for workovers and future development drilling.

AAPG Search and Discovery Article #90956©1995 AAPG International Convention and Exposition Meeting, Nice, France