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The article presents the results of laboratory study, coreflow tests, modeling and practical approach of acid treatment applied to remove scales from oil producing wells in sandstone reservoir. The fact of scaling from produced water was determined with using of core tests. Ways to estimate the amount of calcium carbonate scales in near-wellbore region using Oddo – Thomson’s method and coreflow tests were considered. Optimal hydrochloric acid and modification reagent concentrations for Sorovskoye field formation were chosen during laboratory study. Chemical compatibility of chosen acid compositions with the formation water and oil were tested. The results of coreflow tests with using different technological solutions (various acid compositions and mutual solvent as a preflush) were demonstrated. Approach to treatment modeling to remove calcium carbonate scales from near wellbore zone of oil producing wells in a sandstone reservoir was described. It consists of three calculation stages: calcium carbonate scale quantity, acid composition volume and technological efficiency of acid treatment. Acidizing calculation template with optimal treatment design function (type, concentration, volume of acid and estimated production rate after ramp up) was developed. The results of field tests with using treatment modeling have been demonstrated. Comparison of the field tests results and calculated production rate was given. References 1. Folomeev A.E., Sharifullin A.R., Vakhrushev S.A., Davidenko I.S., Proektirovanie kislotnogo vozdeystviya dlya usloviy soleotlagayushchikh skvazhin, ekspluatiruyushchikh terrigennye ob"ekty, na primere Sorovskogo mestorozhdeniya (Designing the acid effect for salt-depositing wells operating terrigenous objects, on the example of the Sorovskoye field), Proceedings of Interregional Scientific and Technical Conference “70 let nauchnykh issledovaniy i proektirovaniya obustroystva mestorozhdeniy nefti i gaza” (70 years of research and design for the development of oil and gas fields),Ufa, September 21–22, 2017, Ufa: Publ. of BashNIPIneft', 2018, pp. 205–216. 2. Folomeev A.E., Faizov R.A., Sharifullin A.R. et al., An integrated approach in justifying the choice of technology for combating scaling in oil wells (In Russ.), Inzhenernaya praktika, 2018, no. 06–07, pp. 98–104. 3. Oddo J.E., Tomson M.B., Method predicts well bore scale, corrosion, Oil and Gas Journal, 1998, June, pp. 107–114. 4. Sidorovskiy V.A., Vskrytie plastov i povyshenie produktivnosti skvazhin (Formation drilling and increase well productivity), Moscow: Nedra Publ., 1978, 256 p. 5. Economides M.J., Nolte K.G., Reservoir stimulation, New York: JohnWilley & Sons, LTD, 2000, 824 p. 6. McLeod H.O., Jr. Ledlow L.B., Till M.V., The planning, execution and evaluation of acid treatments in sandstone formations, SPE-11931-MS, 1983. 7. McLeod N.O., Matrix acidizing, Journal of Petroleum Technology, 1984, v. 36, pp. 2055–2069. |
