Method for representing non-linear relationship of oil-water relative permeability curve at ultra-high water cut stage

Abstract

The invention provides a method for representing a non-linear relationship of an oil-water relative permeability curve at an ultra-high water cut stage. The method comprises the steps of selecting typical oil-water relative permeability data capable of representing the physical property of a block or an oil reservoir; judging the form of a relation curve between the oil-water relative permeability at the ultra-high water cut stage and water saturation; constructing a functional relational expression suitable for the relation curve between the oil-water relative permeability at the ultra-high water cut stage and the water saturation; and solving coefficients in the functional relational expression for the relation curve between the oil-water relative permeability at the ultra-high water cut stage and the water saturation by using a least square method. The method for representing the non-linear relationship of the oil-water relative permeability curve at the ultra-high water cut stage is used for mathematically representing the non-linear rule of the relative permeability curve at the ultra-high water cut stage and lays the foundation for deriving an oil reservoir engineering calculating method suitable for the ultra-high water cut stage, so that the water driving development effect and predictive index variation tendency of an ultra-high water oil reservoir are accurately evaluated, and the production practice of oil field development is directed.

Description

technical field [0001] The invention relates to the technical field of oilfield development, in particular to a characterization method for the relationship curve between oil-water relative permeability ratio and water saturation in ultra-high water-cut period (abbreviated as oil-water phase-permeability ratio curve in ultra-high water-cut period). Background technique [0002] There are many domestic studies on the law of oil-water two-phase seepage, mainly focusing on the influencing factors of the relative permeability curve, the calculation method of the relative permeability curve, and the characteristics of the relative permeability curve. There are few studies on curves. The foreign research on the phase permeability curve is basically the same as that in China. [0003] In the laboratory, the relationship curve between the ratio of oil phase and water phase relative permeability and water saturation obtained by displacing crude oil with water is called the relations...

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Problems solved by technology

For example, some units have nonlinear characteristics of water drive curves bending upwards during the period of ultra-high water cut, while the traditional Type A and Type B water drive characteristic curves are all linear, which cannot be used for the calibration of recoverable reserves and development effects of such units Evaluation etc.

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