Визначення ефективності застосування композиційного інгібітора солевідкладень у привибійній зоні карбонатних пластів при заводненні

Le résumé fourni par la source

The object of research is the formation processes and prevention methods of inorganic scale deposits (calcium carbonate CaCO₃, calcium sulfate CaSO₄, and barium sulfate BaSO₄) in downhole equipment and the near-wellbore zone (NWZ) during waterflooding of carbonate reservoirs. The problem addressed concerns the insufficient effectiveness of existing approaches to simultaneous prediction and prevention of carbonate and sulfate scale deposits in well equipment and the NWZ under varying thermobaric conditions and incompatible water mixing. A novel composite inhibitor based on phosphonic acids was investigated, comprising 1-hydroxyethylidene-1,1-diphosphonic acid (HEDP), diethylenetriamine-penta(methylenephosphonic acid) (DTPMP), and polyethylenepolyamine-N-methylphosphonic acid (PAF-1), as well as ammonium chloride, isopropyl alcohol, 5% hydrochloric acid solution, and water. Static and dynamic testing demonstrated inhibition efficiency exceeding 90% at a concentration of 30 mg/L across a temperature range of 60–120°C. A positive synergistic effect was identified between HEDP/PAF-1 and DTPMP/PAF-1 components. Without inhibitor application, core permeability in carbonate samples decreased to 55% of the initial value due to scale deposition; the studied inhibitor composition preserved permeability at 92–95%. The minimum operating concentration under dynamic conditions was 25–30 mg/L. The distinctive features of the obtained results lie in the quantitative characterization of the synergistic effect (Em/Ea = 1.085–1.091) for phosphonic acid pairs and the development of an empirical model for predicting NWZ permeability reduction with a coefficient of determination of 0.99. The results are explained by the synergistic interaction among components and their adsorption on the carbonate rock surface. The findings can be applied in designing inhibitor protection technologies for producing wells in carbonate reservoirs, particularly at late-stage field development.

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