Characterization method and device for low-efficiency water injection belt of ultra-high water-cut period oil reservoir

Abstract

The invention discloses a characterization method and device for a low-efficiency water injection belt of an ultra-high water-cut period oil reservoir. The method comprises the steps: obtaining production dynamic data of an oil-water well, and screening out a well group of which the probability of containing a low-efficiency water injection belt reaches a first preset value according to the production dynamic data; calculating the stage water storage rate of each small layer in the well group with the probability of containing the low-efficiency water injection belt reaching the first preset value, and screening out a horizon of which the existence probability of the low-efficiency water injection belt reaches a second preset value according to the stage water storage rates; carrying out single-layer analysis and calculation on each horizon with the existence probability of the low-efficiency water injection belt reaching the second preset value, and determining the horizon where the low-efficiency water injection belt is located; and based on a grid system, performing analysis and calculation on grids in the horizon where the low-efficiency water injection belt is located, and determining low-efficiency water injection grids and the development level of the low-efficiency water injection grids. The method can determine the horizons, the development position and the developmentlevel of the low-efficiency water injection belt, and improves the representation effect of the low-efficiency water injection belt.

Description

technical field [0001] The invention relates to the technical field of oil and gas field development, in particular to a method and device for characterization of low-efficiency water injection zones in oil reservoirs in ultra-high water-cut periods. Background technique [0002] In the long-term water flooding development process of the oilfield, the heterogeneity of the reservoir will cause the unbalanced displacement of the injected water, resulting in significant differences in the pressure and saturation distribution of the fluid in the reservoir. Especially after the reservoir reaches the ultra-high water cut period, the difference between the fluid field and pressure field in different parts of the reservoir becomes more obvious, and the injected water circulates inefficiently in some areas, forming an inefficient water injection zone, which leads to The recoverable reserves are reduced, the oil displacement effect is poor, and the economic benefits are reduced. Ther...

AI Technical Summary

Problems solved by technology

[0005]The existing technology can only roughly judge whether there is a low-efficiency water injection zone in a certain well group, but cannot confirm the layer, development location and development of the low-efficiency water injection zone. Level, less effective in characterization of low-efficiency water injection zone

Images