Gelled Acid vs. Self-Diverting Systems for Carbonate Matrix Stimulation: an Experimental and Field Study

The paper considers the choice of the optimal acid treatment technology using chemical flow divertion, for low-temperature heterogeneous and depleted carbonates, based on the analysis of field data, a complex of physico-chemical and core studies. To increase the efficiency of acid treatments of wells that operate the specified reservoir, two technologies of chemical flow divertion (using a gelled acid (GA) and a self-diverting acid (SDA) are considered in the paper. It was revealed that during acid treatments using SDA a longer exposure time of the reagent in the bottom-hole zone (BHZ) of the well is required, as a result of which the planned efficiency for the conditions of the reservoir under consideration is not achieved. By means of core studies, a higher efficiency of using GA under considered conditions was confirmed. The results of physico-chemical and core studies were used to simulate acidizing and adapt treatment designs. Field study of the treatment technology of producing wells with the use of GA was carried out. According to the results of well logging, there is an increase in the working inflow intervals after treatment. The performed field studies confirmed the results of core studies, theoretical studies and physico-chemical surveys.