An Overview of HF Acid as Applied to the Wilcox Sand in Reddell Field, Southwest Louisiana

Abstract

Abstract The Wilcox reservoir in South Central Louisiana's Reddell Field has responded quite favorably to slow-reacting HF acid treatments. A historical perspective, dating back to 1981, is the basis for the comparison of traditional HF acid (12% HCl – 3% HF) systems to that of the slow-reacting HF acid system. These documented benefits are listed below:Two-to four-fold production increaseAccelerated recovery of well productionReduced workover fluid recovery time from 24 months to 2 monthsIncreased success rate associated with stimulation from 40% to 90% The improved performance was achieved because of careful attention to reducing chemical incompatibilities. Separation of the HF fluids from the potassium chloride workover fluids and the proper choice of HC1-HF concentrations for the Wilcox formation mineralogy dramatically reduced secondary plugging from the HF treatment. This paper discusses Wilcox formation mineralogy and its susceptibility to formation damage. In addition, the paper compares conventional acid treatments to slow-reading HF acid treatments. Finally, criteria are suggested regarding applications of HF acid for similar formations.