Steamflood Modeling and Scale Up in a Hetrogeneous Reservoir

K. Dehghani, W. M. Basham, L. J. Durlofsky, and K. E. Tucker

A study was undertaken to investigate the effects of different levels of reservoir description for modeling the steamflood process in Midway-Sunset 26C south. This reservoir is highly stratified and interbedded with fine scale heterogeneities. The study also included development of a methodology for coarsening very detailed geostatistically derived models so that the effects of fine scale heterogeneities on the steamflood performance prediction can be captured.

Porosity and permeability cubes with three different levels of detail in layering were generated geostatistically for a 30 acre area in the 26C south using data from 57 wells. Cross section models were extracted from these cubes in both dipping and non-dipping structures for steamflood simulations using field injection data and the results were compared. The most detailed models were coarsened by two methods. In the first method, the impermeable layers were retained and the permeable sands coarsened by averaging each 10 layers. In the second method the dominant flow paths in the cross section are identified and used to selectively scale up the reservoir properties, leaving detail in regions where required and coarsening in other regions.

The results showed that the detailed geostatistical model gives a more accurate performance prediction than a coarse geostatistical model. The results also showed that the most accurate coarsened models were obtained by applying the general scale up technique.

AAPG Search and Discover Article #91019©1996 AAPG Convention and Exhibition 19-22 May 1996, San Diego, California