Currently one of the main features of the development of low-permeability reservoirs is intensive waterflooding at high injection pressures to achieve targeted production compensation and increase the sweep efficiency. As the injection pressure rises and is exceeded over the rock fracture pressure, spontaneous development of technogenic fractures along the lines of maximum horizontal stresses is observed - the effect of auto-hydraulic fracturing. In such conditions, the waterflooding regime requires careful monitoring of the operating parameters of the entire reservoir pressure maintenance system - fr om cluster pumping stations to injection wells. Insufficient control can lead to premature flooding of production wells and the formation of zones with abnormally high reservoir pressure, in which there is no possibility of conducting geological and engineering operations. This leads to losses in oil production and failure to achieve the design oil recovery factor, as well as an increase in operating costs for the gathering, treatment and injection of an ineffective volume of water.
The paper describes methods for identifying problem pumped zones and identifying injection wells in which it is necessary to lim it injectivity. The analysis of the infrastructure of the reservoir pressure maintenance system was carried out. Scenario calculations were performed on a hydrodynamic simulator, based on the results of which the optimal values of injectivity and bottomhole pressure were determined. An integrated approach to optimizing waterflooding regimes in selected areas is proposed in order to reduce oil production losses, which makes it possible to increase technological and economic efficiency. The results of pilot projects aimed at limiting the ineffective injection volume of a working agent at the Priobskoye field are presented.
References
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