Compositional Simulation Using Three-Dimensional Geologic Description in Slaughter Field - Hockley County, Texas

by
Lois Katharine Folger, B.S., M.B.A., M.S.E.

University of Texas at Austin, 1995
Supervisors: Larry Lake
Kamy Sepehrnoori

Lois Katharine Folger,

A fully compositional simulation was constructed for final design optimization and monitoring of the Sundown Slaughter Unit CO₂ Project. The model area comprises 355 acres and consists of two waterflood patterns. The model uses a detailed three- dimensional geologic characterization. A very good overall history match was attained for the model and for individual wells without rate constraining producing wells. The model is an effective tool to better understand the CO₂ miscible process and to aid in project reservoir management. Discounted cash flow analysis of simulation output was performed over a wide range of oil prices. Several injection schemes yield similar economics. Only those injection schemes requiring large initial slugs of CO₂ or large gas to water volumes had poor economics. The three-dimensional geologic characterization provides a novel approach to defining the layers in the model. The impact of the number of layers on predicted waterflood and CO₂ flood performance was evaluated. different layering systems were selected from the geologic model to represent actual geology in varying detail. Output from the models showed that the number of layers did not have a large impact on primary and secondary oil recovery. However, for a CO₂ flood, the number of layers significantly affected tertiary oil recovery. Tertiary oil recovery decreases with increasing number of layers. The impact of total injection rates on recovery was also investigated. Tertiary oil recovery was found to be very sensitive to input injection rates. Decreases in injection rates caused significant reductions in tertiary oil recovery.

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