Identifying the efficiency factors on the basis of evaluation of acidizing of carbonate reservoirs

Abstract

This study was carried out to determine the optimal flow and rate of injection of acid compounds during acidizing treatments of formations and to determine the factors that influence the technological and economic efficiency of implementing such technology. The research included evaluating the results of the industrial experimental work performed to implement the technology of large-volume acid treatment, analyzing formation treatments with relatively high specific volume of acid compositions, as well as studying the results of the performed acid fracturing. Altogether, the undertaken statistical and factor analyses covered the results for 180 borehole operations. The results of the study confirmed the hypotheses about the influence of the injection rate and specific flow of the acid composition on the efficiency of the treatments, i.e. the increase of acid composition flow, and identified the factors that increase the risk of performing inefficient operations: exceeding the hydraulic fracturing pressure in the process of implementing the technology significantly increases the risk of water encroachment in the well after the treatment; energy level of the formation: the level of reservoir pressure in the desired production target is 40% below the initial one; the presence of active water-saturated feed zones that maintain the formation pressure in the process of production but increase the risk of water breakthrough.