A water-flooding reservoir water cut prediction method and its prediction device

Abstract

The invention provides a method and device for predicting the moisture content of a water-drive oil reservoir. The method comprises the following steps that the recovery degree R data and moisture content fw data of a sample point of a target oil pool are obtained; linear regression fit is conducted on a vertical coordinate and a horizontal coordinate, wherein the formula lg[(1-fw) / fw is treated as the vertical coordinate, and the recovery degree is treated as the horizontal coordinate, and thus the linearity curve graph of the formula and the recovery degree is obtained; the ultimate recoveryfactor E<R> when the moisture content reaches an economic limit moisture content f<wL> is obtained according to the linearity curve graph; a recovery degree history initial value R<0> and a moisturecontent history initial value f<w0> are obtained by combining the linearity curve graph and the following moisture content expression; and the moisture contents of an oil field under different recovery degrees are calculated according to the moisture content expression, namely the prediction value of the moisture content of the water-drive reservoir. The method calculates the formula of history moisture contents and the recovery rate of a specific oil field based on actual exploration dynamic data of the oil field, and accordingly change of the moisture content with variation of the recovery degree through a current exploration mode is predicted. The method more accords with the reality of the oil reservoir, and the moisture content accuracy predicted by the established formula is higher.

Description

technical field [0001] The invention belongs to the technical field of oil field development, and in particular relates to a method for predicting water content of a water drive reservoir and a predicting device thereof. Background technique [0002] Through the research on the water drive curve and the statistics of the actual production data of the oil field, it is proved that there is a certain relationship between the water cut and the recovery degree of any water drive reservoir. Comprehensive reflection of flow law, using the relationship between water cut and recovery degree can determine the change of water cut with recovery degree. This relationship depends not only on reservoir parameters such as heterogeneity of reservoir, fluid properties, water body size and fluid distribution, but also on human factors such as development well pattern, production method and working system. In actual oilfields, the parameters of each reservoir vary greatly, and the development ...

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Problems solved by technology

However, the formula does not have any theoretical derivation, it is just an assumption, and the constant a has no physical meaning

[0009] There are two main problems in the existing water cut and recovery degree relationship curve diagrams. One is that the Tong’s diagram obtained based on statistical laws 30 years ago cannot be well applied to the current water flooding reservoirs. The predicted Moisture content is often much different than the actual one, which has certain limitations; second, the revised chart formula only artificially modifies the coefficient 7.5 in Tong's chart formula to other constants, which lacks scientific nature

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