Acid treatment of carbonate reservoir with a new dual action microemulsion: Selection of optimal application conditions

Abstract

Complex emulsifying systems based on acid have been widely used in petroleum production. The advantage of these agents is that the rock dissolution rate is slow and the corrosion activity is reduced. This allows acid to penetrate deeper into the reservoir to increase the drainage area of the well while reducing the destructive impact on the surface of downhole equipment. This work is a continuation of the study of a unique acid emulsion for stimulation of carbonate reservoirs, which is already common in the fields in Russia. The new emulsion has a dual action, capable of forming wormholes in the bottomhole area and dissolving paraffin. The application of a single composition significantly reduces the cost of oil production. The main advantage of the technology is that it does not require workover crew when performing the treatment. The accumulated production experience in the implementation of acid treatments without the workover crew can evaluate whether this technology can be further popularized, showing a very broad prospect. We substantiated the selection criteria of candidate wells for stimulation of reservoir by double-action emulsion. The groups of effective and ineffective operations were determined by linear discriminant analysis. We can identify the factors that determine the final effectiveness of the measure through the analysis of field data. In order to ensure that the predicted value is highly consistent with the actual value, We developed a statistical model to estimate the potential increase in oil flow rate after acidizing. The model was piloted on two wells, which can better justify the design of measures and increase their final efficiency by 17–23%. The results confirm that acidizing technology of carbonate reservoir without workover crew is an excellent alternative to standard acidizing, characterized by reduced operating well time and improved profitability.