Method and device for determining water cut rate and water cut rise rate of a reservoir

Abstract

The invention provides a method and device for determining the water cut rate and water cut rise rate of an oil reservoir. The determination method includes: determining the actual recovery degree and water cut of the oil reservoir, drawing a scatter diagram of the actual recovery degree and water cut of the oil reservoir; Fitting the scatter diagram of oil production degree and water cut, the initial water cut of the reservoir, the oil recovery degree at the initial water cut of the reservoir water cut, and the final crude oil oil recovery at the limit water cut of the reservoir water cut are obtained. Recovery factor: Determine the relationship between water cut rise rate and water cut rate, and the change law of water cut rise rate with recovery degree, and determine the change of water cut rise rate in water flooding reservoirs. The invention also provides a device for determining the water cut rate and water cut rise rate of the oil reservoir. The method and device of the present invention consider the actual oilfield production data, and can more truly determine the water cut rate and water cut rise rate of the oil reservoir.

Description

technical field [0001] The invention relates to a method for determining the water content and rising rate of the oil reservoir based on the actual production data of the oil reservoir, and belongs to the technical field of oil reservoir exploitation. Background technique [0002] Water cut, 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 oil field, it is found that there is a certain relationship between the water cut and the water cut rise rate of the water flooding reservoir and the degree of recovery. Reflecting that, using the water cut and the relationship between the water cut rising rate and the degree of recovery can determine the change of the rising rate of the water cut with the degree of recovery. This relationship depends not only on reservoir parameter...

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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.

[0008] The above method proposes that as long as the oil-water relative permeability curve is known, the change of the oilfield water cut rise rate 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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