When developing oil fields with bottomhole pressures in the wells below the saturation pressure of oil with gas, oil degassing zones will be formed in the bottomhole formation zone with different values of the phase mobility ratio, depending on the degree of bottomhole pressure decrease below the bubble point pressure. Under such operating conditions, the speed of movement of the gas phase and water will be significantly higher than the rate of oil filtration, which will lead to a decrease in the productivity index of the well. In the second half of the twentieth century, petroleum engineers, as a result of research, established the maximum permissible bottomhole pressure limit at 80% of the oil saturation pressure. In the current field development conditions, more and more production wells operate with bottomhole pressure close to the bubble point pressure, therefore, the relevance of determining the optimal bottomhole pressure relative to the bubble point pressure has significantly increased. At present, using modern means of monitoring the well operation mode, it is possible to determine this ratio in almost every field, using hydrodynamic studies of production wells equipped with an electric centrifugal pump. By changing the frequency of the electric motor using a frequency converter, and controlling the pressure at the pump intake using a thermomanometric system, it is possible to change the operating mode of the well and monitor the change in the productivity factor. As a result of the studies carried out, a limit is established for lowering the bottomhole pressure, below the saturation pressure of oil with gas, at which the maximum production rate of the production well is ensured. The article offers recommendations for maintaining a given bottomhole pressure as the main conclusions.
References
1. Nazarova L.N., Nechaeva E.V., The analysis of influence of bottomhole pressure decrease under saturation pressure on the oil recovery (In Russ.), Neftyanoe khozyaystvo = Oil Industry, 2013, no. 1, pp. 83–85.
2. Kim V.G., Baymukhametov M.A., Review of well-known methods of hydrodynamic studies of wells operating at bottomhole pressure below saturation pressure (In Russ.), Sciences of Europe, 2019, V. 45, pp. 51–57.
3. Lysenko V.D., Razrabotka neftyanykh mestorozhdeniy. Effektivnye metody (Development of oil fields. Effective methods), Moscow: Nedra-Biznestsentr, 2009, 552 p.
