نوع مقاله : مقاله پژوهشی
نویسندگان
1 بخش مهندسی شیمی، دانشکده مهندسی شیمی نفت و گاز، دانشگاه شیراز، شیراز، ایران
2 بخش مهندسی نفت، دانشکده مهندسی شیمی نفت و گاز، دانشگاه شیراز، شیراز ، ایران
چکیده
کلیدواژهها
موضوعات
عنوان مقاله [English]
نویسندگان [English]
Potential formation damage assessment due to the incompatibility of injected acid and reservoir crude oil is necessary before acid stimulation. Acid-oil emulsion, sludge formation, and applicability of controlling additives must be evaluated according to RP-42. In the last revision of RP-42 (1990), there are not enough details for conducting the tests including mixing conditions, data quantification, and the comparison of various experimental results. In addition, it has been explicitly mentioned that the results were not guaranteed, and RP-42 just included some recommendations to improve the accuracy of tests. In this paper, along with analyzing RP-42 in detail and presenting a literature review, some ambiguities are distinguished in experimental conditions including failure to consider the real reservoir temperature during emulsification, ambiguous mixing conditions of acid and crude oil, and its resulted shear, uncertainty associated with the sludge determination and its washing method. Therefore, the acid-oil compatibility test procedure has been revised based on the literature and experimental observations. The most important modifications are pre-heating the acid and oil phases and the container to the reservoir temperature, mixing with the same intensity as the shear of injecting acid into the reservoir, emulsion, and sludge evaluation by an integrated experiment, using multi-step screening with various mesh size for sludge separation, microscopic study of emulsion droplets and their comparison with the reservoir pore size distribution to recognize the clogging potential, introducing useful fluids to wash and purify the formed sludge, removing the destructive effects of ferric ions, and study completion by parallel conducting injection tests in core samples or micromodel. The revised procedure will help engineers to design acidizing processes more effectively, leading to lower costs, as well as paving the way for more accurate and realistic assessment of emulsion and sludge formation in the laboratory.
کلیدواژهها [English]
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