Reasonable layering method of water injection oil reservoir

Abstract

A reasonable layering method of a water injection oil reservoir comprises the steps: S10, establishing a plurality of typical injection-production well group models; S20, performing numerical simulation of multi-layer commingled injection; S30, drawing a Lorentz curve according to the simulated cumulative percentage and yield cumulative contribution rate of each layer of reserves before water breakthrough; drawing a Lorentz curve according to the cumulative percentage of reserves of each layer after water breakthrough and the cumulative contribution rate of the yield to obtain Lorentz coefficients before and after water breakthrough; S40, calculating equilibrium displacement criteria before and after water breakthrough; S50, introducing an LSTM neural network to carry out simulation rationality supervision to obtain a final equilibrium displacement criterion threshold value; and S60, judging the layering rationality of the well group. According to the invention, the Lorentz coefficientis introduced as an evaluation standard, the water breakthrough time level difference of each layer before water breakthrough and the water content rise rate level difference of each layer after water breakthrough which comprehensively consider each dynamic and static factor are taken as economic and technical boundaries of layered water injection. The situation that injected water is not evenlydistributed in the longitudinal direction is improved, the accuracy of oilfield flooding stratification evaluation is improved, the flooding utilization rate is increased, and the method is an effective measure for improving the flooding effect.

Description

technical field [0001] The invention relates to the technical field of petroleum exploitation, in particular to a reasonable layering method for water injection oil reservoirs. Background technique [0002] Due to the difference in the physical properties of the sub-layers in the reservoir system, their water absorption capabilities are different. During general water injection, most of the water injected into the oil layer is absorbed by the high-permeability layer with a small thickness, and the water absorption profile of water injection is very poor. Uniformity, low utilization rate of water injection, serious invalid water circulation, seriously restrict the efficient and effective development of oil reservoirs. [0003] Layered water injection is a very effective method to solve the above problems. Layered water injection is to use packers to combine small layers with similar reservoir physical properties and development conditions to inject water into one layer, and ...

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Problems solved by technology

However, this is still the equivalent single-phase flow idea

[0005] On the other hand, the interaction of various simulation methods among well group parameter factors will lead to the fluctuation of the Lorentz coefficient in a certain simulation time step; while the selection of the equilibrium displacement standard is based on the optimization of subjective settings. Empirical methods such as values ​​and typical values ​​will lead to locally reasonable stratification in the time step where the Lorenz coefficient fluctuates, but it will have a great cumulative impact on the overall simulation results, which will result in high cost of test production and test injection when reflected in reality

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