Achieving effective fracture lengths in carbonate formations by fracture acidizing has long been a recognized industry challenge. Severe fluid loss is generally considered a major factor limiting the effectiveness of acid fracturing treatments. A unique new acid fracturing fluid has been developed to control fluid loss. It has been tested in numerous laboratory and field studies. Test results confirm that this new fluid system improves live acid penetration in carbonate reservoirs by controlling acid fluid loss.
This paper discusses the technical basis for the development of this new fluid system. Laboratory test results are included. It also describes the results of field case histories in which the new system was successfully utilized in the Permian Basin of West Texas and the Williston Basin of North Dakota to control acid fluid loss in carbonate acid fracturing. Production comparisons show a substantial improvement in well performance from these wells following treatments that utilized this new system.