EIKREM,VERN, PETER NEDERLOF, JOHN STAINFORTH, CHARLES TUCKER, and BOB ELSINGER, Shell Oil Company, New Orleans, LA, USA

Abstract: Three Years of Production at the Mars Field: Reservoir Performance Exceeds Initial Forecast

The Mars Field was discovered in 1989 in the Mississippi Canyon area in the Gulf of Mexico, approximately 130 miles southeast of New Orleans. The field consists of seven major and numerous minor reservoirs, ranging in age from Upper Miocene to Lower Pliocene. Recoverable reserves from this stacked series of turbidite sands are currently estimated at 730 million BOE.This year, the field will reach its peak production with anticipated oil production of 140,000 STB/D and 140 MCF/D of gas. Production started in July 1996 after the Mars tension leg platform was installed in a record water depth of 2940 ft. Platform construction was completed in three years and total development costs will approach one billion dollars. Fabrication and installation of facilities and pipelines account for about 55% of the capital outlay while the remaining 45% is marked for development wells. Shell Deepwater Production Incorporated operates the field and has a 71.5% working interest while British Petroleum holds the remaining 28.5%.

At present, the Mars Field has been on production for just over three years. During this time, a wealth of data has become available and in this paper we will discuss drilling results along with pressure, well performance, and production data and their impact on the understanding of the geological architecture of the field. These production data provide an invaluable 4th dimension of time, which can be used to predict reservoir performance in future discoveries with few well penetrations. Initial production models have generally underestimated the performance of the Mars field: compressibility may have been understated, reservoir sands appear to be better connected and aquifer support is better than predicted from the initial geological, petrophysical, and geochemical models.

AAPG Search and Discovery Article #90923@1999 International Conference and Exhibition, Birmingham, England