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Waterflooding practice shows the negative consequences, referred to by experts as “viscous instability of the displacement front”, “finger-shaped displacement front”, “premature water breakthrough”, “fractal geometry of the displacement front” and other versions, including those related to the instability of the displacement front. All these phenomena eventually lead to a violation of the reservoir pressure maintenance – well optimization –pumping equipment control. Therefore, it is important to substantiate the physical mechanism of the formation and advance of the displacement front and the early forecast of growth or faster rate of unstable movement of the water phase in the flow at certain sites and stages of the dynamic process of non-stationary waterflooding. The article presents fragments of a scientific and methodological system approach that includes a number of independent tasks that are organically combined with non-stationary flooding in conditions of instability of the displacement front. Among the necessary and priority tasks determination of stagnant and poorly drained zones of the reservoir is considered by calculating the coefficients of normalized specific production rates for oil, water and liquid. Distribution of the producing well stock by technological groups for oil and water recovery according to the Pareto principle is analyzed. The mutual interference of wells of the producing and injection stock is determined by establishing a statistical and causal relationship. It is discussed the optimization of the system reservoir – well – subsurface equipment by monitoring and the control operating practices of production and injection wells based on calculations of the dynamics of the discriminant criterion for oil and water growth models. Regulation of pressure characteristics of pumps in accordance with the requirements of the optimization conditions of the system reservoir – well – subsurface equipment is considered. It is shown the application of the obtained criteria and decisive rules in the form of a program for control operating practices of the production and injection well stock and a program of geological and technical measures to involve in the development of stagnant and poorly drained zones and increase the productivity of marginal wells. The article considers as an example an element of the productive formation of the Nong-Yegan field. References 1. Mirzadzhanzade A.Kh., Shakhverdiev A.Kh., Dinamicheskie protsessy v neftegazodobyche: sistemnyy analiz, diagnoz, prognoz (Dynamic processes in the oil and gas production: systems analysis, diagnosis, prognosis), Moscow: Nauka Publ., 1997, 254 p. 2. Mandrik I.E., Panakhov G.M., Shakhverdiev A.Kh., Nauchno-metodicheskie i tekhnologicheskie osnovy optimizatsii protsessa povysheniya nefteotdachi plastov (Scientific and methodological and technological basis for EOR optimization), Moscow: Neftyanoe khozyaystvo Publ., 2010, 288 p. 3. Shakhverdiev A.Kh., Sistemnaya optimizatsiya protsessa razrabotki neftyanykh mestorozhdeniy (System optimization of oil field development process), Moscow: Nedra Publ., 2004, 452 p. 4. Shakhverdiev A.Kh., System optimization of non-stationary floods for the purpose of increasing oil recovery (In Russ.), Neftyanoe khozyaystvo = Oil Industry, 2019, no. 1, pp. 44–50. 5. Shakhverdiev A.Kh., Shestopalov Yu.V., Mandrik I.E., Aref'ev S.V., Alternative concept of monitoring and optimization water flooding of oil reservoirs in the conditions of instability of the displacement front (In Russ.),Neftyanoe khozyaystvo = Oil Industry, 2019, no. 12, pp. 118–123. 6. Shakhverdiev A.Kh., Shestopalov Yu.V., Qualitative analysis of quadratic polynomial dynamical systems associated with the modeling and monitoring of oil fields, Lobachevskii Journal of Mathematics, 2019, V. 40, no. 10, pp. 1695–1710. 7. Arnol'd V.I., Teoriya katastrof (Catastrophe theory), Moscow: Nauka Publ., 1990, 128 p. 8. Kreyg F.F., Razrabotka neftyanykh mestorozhdeniy pri zavodnenii (Applied waterflood field development), Moscow: Nedra Publ., 1974, 191 p. 9. Shaohua Gu, Yuetian Liu, Zhangxin Chen, Cuiyu Ma, A method for evaluation of water flooding performance in fractured reservoirs, Journal of Petroleum Science and Engineering, 2014, V. 120, pp. 130–140. 10. Wang Dashun, Di Niu, Huazhou Andy Li, Predicting waterflooding performance in low-permeability reservoirs with linear dynamical systems, SPE-185960-PA, 2017. 11. Nigmatullin R.I., Dinamika mnogofaznykh sred (The dynamics of multiphase media), Part 2, Moscow: Nauka Publ., 1987, 360 p. 12. Rodygin S.I., Water-cut dynamics in oil-saturated porous media under pressure waves propagation. Numerical Simulations (In Russ.), Georesursy, 2012, no. 1 (43), pp. 31–34. |
