Stimulation Practices Using Alcoholic Acidizing And Fracturing Fluids For Gas Reservoirs (1974)

This paper was prepared for the SPE-European Spring Meeting 1974 of the Society of Petroleum Engineers of AIME, held in Amsterdam, the Netherlands, May 29–30, 1974. Permission to copy is restricted to an abstract of not more than 300 words. Illustrations may not be copied. The abstract should contain conspicuous acknowledgment of where and by whom the paper is presented. Publication elsewhere after publication in the JOURNAL OF PETROLEUM TECHNOLOGY or the SOCIETY OF publication in the JOURNAL OF PETROLEUM TECHNOLOGY or the SOCIETY OF PETROLEUM ENGINEERS JOURNAL is usually granted upon request to the Editor PETROLEUM ENGINEERS JOURNAL is usually granted upon request to the Editor of the appropriate journal provided agreement to give proper credit is made. Discussion of this paper is invited. Three copies of any discussion should be sent to the Netherland Section of the Society of Petroleum Engineers, P. O. Box 228, The Hague, the Netherlands. Such discussion may be presented at the above meeting and, with the paper, may be considered for publication in one of the two SPE magazines. Abstract Stimulation treatments of gas bearing reservoirs using alcoholic based fluids are producing improved results over water based producing improved results over water based fluids. By reducing the formation retention characteristic of the stimulating fluids, water blocking is reduced or eliminated and rock wettability and saturation changes do not occur. Well clean-up time after treatments is reduced so that productivity tests may be quickly obtained. The increased volatility of the treating fluids requires special care and handling procedures with extreme caution toward safety standards being fully emphasized. Introduction Alcohol based acidizing fluids have proved highly successful in stimulating proved highly successful in stimulating production from "problem wells" in sandstone production from "problem wells" in sandstone formations. Alcoholic fracturing fluids have also been developed for those formations requiring a greater degree of stimulation. The fracturing fluids are relatively new and have not yet been widely used, but they are designed to provide the same advantages as the acidizing fluids. The primary advantage of the alcoholic fluids is the better and more rapid clean-up properties provided by the added alcohol. They properties provided by the added alcohol. They are particularly useful in gas producing formations, especially those with high clay content. Stimulation treatments of gas wells are often unsuccessful because of slow and incomplete clean-up of stimulation fluids following treatment. These clean-up problems are often the result of water blocking in the critical matrix surrounding the wellbore. Water blocking is caused by the capillary forces present in porous rock and the high mobility ratio of gas and water. Water remains around the wellbore following a stimulation or workover treatment. When the well is put back on production, the gas forces some of the water out of the rock; but when the gas breaks through, a high water saturation is left around the wellbore. This high water saturation reduces the effective permeability of the sand to gas (Fig. 1).