A method and a device for predicting the change of water cut rise rate of a water flooding reservoir

Abstract

The invention provides a method and a device for predicting the change of water cut rise rate of a water flooding reservoir. The method includes: determining the actual water cut rise rate and water cut of the reservoir, and drawing the scatter plot of the actual water cut rise rate and water cut of the reservoir; based on the relationship between water cut rise and water cut, fitting the scattered plot of actual water cut rise and water cut to obtain the initial water cut of the reservoir, the oil recovery degree when the water cut is initial water cut and the ultimate oil recovery factor when the water cut is limit water cut; determining the law of water cut rise rate with the recovery degree, and determining the water drive reservoir water cut rise rate change. The invention also provides a prediction device for water cut rise rate change of a water flooding reservoir. The method and the device of the invention consider the actual oil field production data, and can more truly predict the variation rule of the water cut rise rate.

Description

technical field [0001] The invention relates to a method for predicting the change of the water cut rising rate of an oil reservoir based on oil field production dynamic data, and belongs to the technical field of oil reservoir development. Background technique [0002] Water cut rise rate and recovery degree are important production indicators of oilfield development, and their changes reflect the quality of oilfield water flooding development to a certain extent. Through the statistics of the actual production data of the oilfield, it is found that there is a certain relationship between the water cut increase rate and the recovery degree of the water flooding reservoir. The relationship between water cut rising rate and recovery degree can determine the change of water cut rising rate with recovery degree. This relationship not only depends on reservoir parameters such as heterogeneity of the reservoir, fluid properties, water body size, and fluid distribution, but also ...

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Problems solved by technology

However, there will be a large error between the calculation result and the actual data near the two endpoints of irreducible water saturation and residual oil saturation. During the calculation process, this error will be retained and will be substituted into the subsequent reservoir analysis. Detrimental effects on reservoir dynamic analysis and planning scheme preparation

In particular, the above-mentioned relative permeability curve characterization method has the following disadvantages: ① The change of oilfield development index in the low water-cut stage is not consistent with the water drive characteristic curve; ② The relative permeability curve at a higher water injection multiple has a piecewise nonlinear feature, and the oil-water relative permeability ratio has little influence on the water cut in actual production, so the relative permeability curve at this stage The characterization accuracy requirements of the oil field are not high, and the change of oilfield development index conforms to the characteristics of the water drive curve; Then it is completely linear, and the linear relationship is only suitable for the middle section of the relative permeability curve, but cannot represent the complete relative permeability curve.

[0007] The above method proposes that as long as the oil-water relative permeability curve is known, the change of the water cut increase rate of the oilfield can be predicted. However, the actual water cut change of the oilfield is not only related to the oil-water relative permeability curve, but also has a lot to do with the well pattern and development mode of the oilfield. It cannot reflect the actual production characteristics of the oilfield well, and cannot be well used in the actual oilfield water flooding development effect evaluation and index prediction, and its practicability is poor

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