Quantitative evaluation method of oil reservoir water flooded layer

Abstract

The invention provides a quantitative evaluation method of an oil reservoir water flooded layer. The quantitative evaluation method comprises the steps that an oil-water relative permeability curve ofa core sample is measured; irreducible water saturation S<wi> and residual oil saturation S<or> of the core sample are obtained, and a movable oil index K<o> and a movable water index K<w> of the core sample are calculated; a K<ro>-K<o> curve and a K<rw>-K<w> curve of the core sample are drawn in a simulated mode; a to-be-evaluated core sample of a target oil reservoir water flooded layer is taken, the irreducible water saturation S<wi>, the residual oil saturation S<or> and water saturation S<w> of the to-be-evaluated core sample are obtained, the relative permeability index K<rf> of the to-be-evaluated core sample is solved, and then the water flooded layer of a target oil reservoir is quantitatively evaluated. According to the quantitative evaluation method, the seepage characteristicsof a reservoir are taken as the basis, core relative permeability testing data serve as the basis, and the trend of the oil-water relative permeability curve changing with the water saturation is analyzed; and based on this, the oil-water relative permeability index is constructed to represent the water flooding degree of the oil reservoir, a logging interpretation model of the oil reservoir is established, and the oil reservoir water flooded layer is evaluated more accurately.

Description

technical field [0001] The invention relates to the field of oilfield development geology, in particular to a quantitative evaluation method for water-flooded layers of oil reservoirs. Background technique [0002] The vast majority of oilfields in China are continental deposits, with serious heterogeneity and insufficient natural energy. They are mainly exploited by water injection, and the reserves of oilfields developed by water injection account for more than 85% of the total reserves. After decades of water flooding development, most oil fields have entered the stage of high water cut and high recovery degree, and one of the main problems faced in the middle and late stages of development is the evaluation of water flooded formations. Whether it is a sandstone reservoir or a conglomerate reservoir, the evaluation of the water-flooded layer is very difficult. The stronger the heterogeneity of the reservoir, the more difficult the evaluation is; The longer the water inje...

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Problems solved by technology

[0004] The main purpose of the present invention is to provide a quantitative evaluation method for water-flooded layers of oil reservoirs, to solve the problem of low evaluation accuracy for water-flooded layers of oil reservoirs in the prior art

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