The efficiency of bottomhole zone hydrochloric acid treatment depends on geological and physical characteristics of the productive formation (formation temperature, fracturing, proximity of water-oil and gas-oil contacts, etc.), the degree of rock dissolution during interaction with acid composition, and formation coverage. To assess the influence of these parameters, an integrated approach is required when planning the design of acid treatment of horizontal wells. In order to improve the efficiency of acid treatment in the conditions of Riphean deposits of the Yurubcheno-Tokhomskoye oilfield, represented by low-temperature dolomitized rocks, a set of analytical and laboratory studies was carried out to determine the optimal treatment technology. The main features of this object are: low share of working intervals in relation to the total length of the open wellbore of production wells, low reservoir temperature, fractured dolomitized reservoir, risks of acid breakthrough into water- and gas-saturated parts of the deposit. In the course of physico-chemical experiments, the prospect of increasing the efficiency of exposure with an acid composition based on 24% HCl, modified by a mutual solvent, which provides an increase in the rate of reaction of the composition with the rock of the Riphean object of the Yurubcheno-Tokhomskoye field, was shown. In order to evaluate the effect of the modified acid composition on the rock matrix, a filtration experiment was carried out, the results of which revealed the formation of a highly conductive dissolution channel, which confirms the effectiveness of the composition. The horizontal well treatment design adapted to the conditions of the Riphean object was developed. Pilot tests of acid treatment technology with the use of modified composition were carried out; the results of the research and the technology effectiveness were confirmed.
References
1. Hill A.D., Schechter R.S., Economides M.J., Nolte K.G., Fundamentals of acid stimulation, In: Reservoir Simulation, John Wiley & Sons Ltd., 2000, 856 p.
2. Bulgakova G.T., Kharisov R.Ya., Sharifullin A.R., Pestrikov A.V., Optimizing the acidizing operations of horizontal wells in carbonate reservoirs (In Russ.), Neftyanoe khozyaystvo = Oil Industry, 2013, no. 6, pp. 102–105.
3. Hoefner M.L., Pore evolution and channel formation during flow and reaction in porous media, AIChE Journal, 1988, V. 34, no. 1, pp. 45–54, DOI: https://doi.org/10.1002/aic.690340107
4. Lund K., Fogler H.S., McCune C.C., Acidization – I. The Dissolution of Dolomite in Hydrochloric Acid, Chemical Engineering Science, 1973, V. 28, no. 3, pp. 691–700.
5. Kristian M., Sokol S., Konstantinesku A., Uvelichenie produktivnosti i priemistosti skvazhin (Increasing productivity and injectivity of wells), Moscow: Nedra Publ., 1985, 184 p.
6. Cherepanova N.A., Maksimova E.N., Chertina K.N. et al., Influence of the carbonate rocks dolomitization in the Eastern Siberia on the acid impact efficiency (In Russ.), Neftepromyslovoe delo, 2022, no. 10(646), pp. 48–53, DOI: https://doi.org/10.33285/0207-2351-2022-10(646)-48-53
7. Folomeev A.E., Magadiev A.F., Khatmullin A.R. et al., Acidizing combined with heat generating system in low-temperature dolomitized wax damaged carbonates, SPE-202069-MS, 2020, DOI: https://doi.org/10.2118/202069-MS
8. Harris O.E., Hendrickson A.R., Coulter A.W., High-concentration hydrochloric acid aids stimulation results in carbonate formations, Journal of Petroleum Technology, 1966, V. 18, no. 10, pp. 1291–1296, DOI: https://doi.org/10.2118/1654-PA
9. Liu H., Coston C., Yassin M. et al., A novel stimulation technique for horizontal openhole wells in carbonate reservoirs – A case study in Kuwait, SPE-105127-PA, 2009, DOI: https://doi.org/10.2118/105127-PA
10. Folomeev A.E., Taipov I.A., Khatmullin A.R. et al., Gelled acid vs. Self-diverting systems for carbonate matrix stimulation: an experimental and field study, SPE-105127-PA, 2009, DOI: https://doi.org/10.2118/105127-PA
