High water-cut oilfield well position determining method based on evolutionary algorithm

Abstract

The invention provides a high water-cut oilfield well position determining method based on an evolutionary algorithm. The method comprises the steps of building an oil reservoir model of a predetermined oil area, and dividing the oil reservoir model into grids; obtaining the oil reservoir data, and obtaining a surplus oil potential enrichment area in a history matching mode according to the oil reservoir data; computing a well position constraint value for representing the surplus oil distribution and injected water waves and volume in the surplus oil potential enrichment area to obtain the well position advantage area; carrying out iteration on an oil well in the advantage area through the evolutionary algorithm to compute a fitness function, and evaluating the fitness function through a Kriging algorithm, wherein the evolutionary algorithm is adjusted according to the fitness function, and the Kriging algorithm considers the multi-dimensional space, the nugget effect and the local weight; obtaining a maximum fitness function value according to the iteration computing of the evolutionary algorithm so as to determine the well position. The improved evolutionary algorithm and the Kringing algorithm serve as the optimization tools, a dynamic potential index is built to reduce the searching space of the evolutionary algorithm, and the optimization computing convergence precision and speed are greatly improved.

Description

technical field [0001] The invention belongs to the technical field of adjusting well positions for development of high water-cut oilfields, and in particular relates to a method for determining well positions in high-water-cut oilfields based on an evolutionary algorithm. Background technique [0002] For the oil reservoirs developed by water flooding in my country, most of them are old oilfields with high water content that have been developed by water flooding for decades. The heterogeneity of underground reservoirs and the complexity of oil-water relationship lead to the distribution of remaining oil being "scattered overall and concentrated locally". "The complex characteristics of the oil field caused great difficulties to the late adjustment of the oil field, and directly affected the water flooding development effect and economic benefits. Determining a reasonable adjustment of the well location is an important main technology for the adjustment of high water-cut matu...

AI Technical Summary

Problems solved by technology

Although the current quality map method considers some static and dynamic attributes of the reservoir, it does not consider the influence of the reservoir driving mechanism, the drainage of the existing well pattern, and the swept volume of injected water on the adjusted well location, which has caused a great impact on the optimized well location. certain error

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