Effect of Formation Damage from Drilling, Completion, and Fracture Treatment onGas Productivity of Frontier Sandstone Wells. Topical Report, October 1989-September 1992

摘要

Based on special core analyses, and well tests before and after trac treatment,there was only minor permanent formation damage in three wells in the Frontier sandstone in the Moxa Arch area of Southwestern Wyoming. The study was performed because of concern that gas productivity in the Frontier sandstone is seriously damaged by the fluids used in drilling, completion, and fracture treatment. As a central part of the study analyses were conducted on cores from one well to measure regained gas permeability after fracture fluid invasion. Best regained gas permeability occurred after foam frac filtrate invasion, but all three frac fluids tested gave acceptable results. However, frac gel did not break properly at reservoir temperature until five times the recommended breaker concentration was used. Routine and special analyses were performed on cores from all three wells. Fibrous illite, present in the pay zone of one well, severely reduces reservoir gas permeability, but its presence is currently unpredictable in the study area.