Document Type : Research Paper
Authors
1
Department of Chemical Engineering, School of Chemical and Petroleum Engineering, Shiraz University
2
Department of Petroleum Engineering, School of Chemical and Petroleum Engineering, Shiraz University, Shiraz, Iran
3
Department of Chemical Engineering, School of Chemical and PEtroleum Engineering, Shiraz University
10.22078/pr.2024.5512.3451
Abstract
Well stimulation through acid injection to near wellbore region is applied to remove deposits and clogging from porous medium and to recover reservoir productivity. However, improper process design and implementation cause different formation damages, and probably complete loss of well production. Despite its high importance, there are no enough studies on acid-induced formation damages such as formation of stable acid-oil emulsion and sludge with some ambiguities in several aspects. As some Iranian oilfields require acidizing then it is imperative to survey the literature. In this paper, a comprehensive study has been done including acidizing process explanation, its affecting factors, and introducing of the recommended approaches with their challenges. The literature review shows that the phenomenon of acid-induced sludge formation has been considered more than acid-oil emulsion. In addition, most studies on emulsion were related to water-oil systems, which would differ profoundly from acid-oil systems due to their complex interactions although they are common in some features with the same fundamentals. Therefore, acid-oil compatibility experiments are crucial, and if they are designed and performed appropriately, they can lead to a more effective oilfield acidizing process. The use of chemical additives is the most applied approach which may come with considerable cost, but its efficacy would be affected by incompatibility of the chemical additives with crude oil or formation rock. In this process, careful attention to the properties of crude oil is particularly important so that optimized acidizing conditions in a region of the reservoir may be undesirable in other areas. Finally, further studies are still required, especially on the novel acidizing approaches, the role of indigenous solid particles, salinity, and the presence of different ions, pressure, and crude oil properties in acidizing effectiveness.
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