Experimental Calibration of a Coupled Reaction-Flow Simulator

U. Mok, F. J. Longstaffe, C. H. Moore, J. S. Dudley, W. D. Gunter, and B. Wiwchar

Two flow-through experiments in sandstone were conducted to assess the impact of artificial diagenesis (neogenesis) during steam-assisted oil recovery in a bitumen reservoir in NE-Alberta, Canada (Clearwater formation). The benchmark experiments were designed to calibrate and validate a reaction-flow simulator (REACTRAN). Because of the system's complexity, the simulator has to be validated in the laboratory before being used in field applications. In the second experiment, reported on here, the impact of neogenesis on preserved core from the field was investigated. Salient features of the experiment are: fluid composition - brine, pH 9.5; injection time - 28 days; temperature - 246°C; sediment - bitumen extracted, immature, litharenite sand; permeability - 3 Darcies system length - 90 cm; flow rate - 10.2 cc/h. The initial and final rock composition were analyzed. We found: (1) small overall permeability reduction (8%); (2) the post-steam core remained unconsolidated; (3) the most reactive sand components are carbonates and the matrix of volcanic rock fragments; (4) many plagioclase grains were dissolved; (5) K-feldspar, smectite, and chlorite were formed. These results show promising agreement between REACTRAN predictions and the laboratory experiments. In the near future, such experimentally calibrated simulators may be effective in predicting beneficial and deleterious reactions that may occur during thermally-assisted oil recovery.

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