Abstract: Reservoir Development of a Shelf-Edge Delta: A Case Study from Mississippi Canyon 109, Gulf of Mexico

W. H. Mills, S. P. Mitchell, G. S. Vinson, III, C. A. Yeilding

The Mississippi Canyon 109 field is a structural-stratigraphic trap, located in 1000^prime of water in the Gulf of Mexico. The first phase of drilling was completed in early 1994 with a total of 30 wells, including 8 dual and 8 horizontal completions. Early field appraisal from well and seismic data suggested the two main pay horizons were middle Pliocene shelf-edge deltas. Subsequent development grilling has substantiated the shelf-edge deltaic model and added significant information on stratigraphic complexities which affected reservoir management decisions.

Reservoirs thickness and rock properties provide an excellent character tie to 3-D seismic data, enabling identification of gross pay and depositional geometries within the main reservoirs. Clinoform features identified on the seismic data are believed to be associated with contemporaneous slumping and progradation of deltaic mouthbar facies. These features suggested the strong possibility of reservoir barriers. Development drilling verified the presence of compartmentalized reservoirs within each of the fields three fault blocks; thus the need for a detailed reservoir model.

The central fault block was performance modeled as a pilot study for waterflood. Quantitative rock property correlations with acoustic impedance were derived from interpretation of cores, logs, seismic data, maps, and fluid data. These correlations were applied to the 3-D seismic acoustic impedance data set to predict porosity, permeability, water saturation, and rock type.

Results of this study have improved the overall understanding of the reservoir architecture within the field and facilitated near-term waterflood planning. Good agreement between seismic rock properties from the model and individual wells was observed. Field performance data and initial simulation results suggest that small scale stratigraphic features have a considerable impact in reservoir performance. A combination of deterministic and stochastic methods to provide sub-seismic details is currently being considered for future modeling.

AAPG Search and Discovery Article #90986©1994 AAPG Annual Convention, Denver, Colorado, June 12-15, 1994