The Benefits of Enhanced Integration Capabilities in 3-D Reservoir Modelling and Simulation

Stephen T. O'Rourke, Austin Ikwumonu

The use of proprietary, closely linked 3-D geological and reservoir simulation software (GEOCAP 2 and MoReS) has greatly enhanced the reservoir modelling process by enabling complete integration of geological and engineering data in a 3-D manner. These software were used to model and simulate a deltaic sandstone reservoir in the Nigerian Forcados Yokri field in order to describe the reservoir sweep pattern.

Well logs, 3-D seismic, limited core data and sequence stratigraphic concepts were used to define a three dimensional depositional model. A detailed correlation of the reservoir genetic units revealed four parasequences comprising mainly upper shoreface and channel sands, both of which have excellent reservoir properties. The intervening flooding surfaces are represented by thin marine shales which in many places have been eroded by overlying channels. These shales are the only intra-reservoir baffles to flow and thus, proper modelling of them was critical to achieving a history match. The detailed correlation was used to generate a 3-D geological model in GEOCAP where petrophysical parameters were assigned. The model was then upscaled and input to the reservoir simulation system MoRe ; this input from 3-D models was achieved much more efficiently than utilising the conventional 2-D structural and property maps. Simulation of the initial GEOCAP model did not yield a proper match with the dynamic reservoir data. Alternative shale models were easily generated and evaluated until an acceptable match was achieved.

By using modelling software that are designed to facilitate the creation and evaluation of detailed 3-D reservoir models, cross-discipline integration of data and expertise is greatly enhanced. The software provides the capability to evaluate multiple reservoir models utilising all relevant data in a time frame that was previously impossible. The result is a better understanding of the reservoir and a commensurate improvement in field development optimisation.

AAPG Search and Discovery Article #91020©1995 AAPG Annual Convention, Houston, Texas, May 5-8, 1995