Method for representing oil-water relative permeability curve under condition of different driving displacement pressure gradients

Abstract

The invention provides a method for representing an oil-water relative permeability curve under the condition of different driving displacement pressure gradients, and belongs to the technical field of reservoir engineering in oil development. The method comprises the following steps that (1) different driving displacement pressure gradients are exerted on a group of rock cores with identical or similar permeability to obtain the relative permeability experiment data of each rock core, then, a permeability curve corresponding to each rock core is made according to the relative permeability experiment data, and next, the relative permeability curve corresponding to each rock core is subjected to normalization processing to obtain an oil-water relative permeability curve corresponding to each rock core; (2) the statistical laws on the water phase maximum relative permeability, the oil displacement efficiency and the pressure gradient are fit out according to the relative permeability experiment data, and the water phase maximum relative permeability and the residue oil saturation degree under different pressure gradients can be solved; (3) a characteristic curve equation of the relative permeability curve corresponding to each rock core is solved.

Description

technical field [0001] The invention belongs to the technical field of petroleum development reservoir engineering, and in particular relates to a characterization method for oil-water relative permeability curves under different displacement pressure gradient conditions. Background technique [0002] The oil-water relative permeability is an important parameter for studying reservoirs, through which the reservoir water injection development dynamics can be simulated and the recoverable reserves can be predicted. This parameter is often obtained through water flooding experiments with cores in the laboratory. The experimental results show that the oil-water relative permeability curve changes when the displacement pressure gradient is changed. At present, the determination of oil-water relative permeability can be divided into steady-state method and unsteady-state method. Among them, the unsteady-state method is widely used because of its short experiment time and coincid...

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Problems solved by technology

In 2007, Zhang Jicheng et al. proposed a method to characterize the relative permeability curve with the relative permeability characteristic curve equation, but this method is not suitable for popularization and application due to too many parameters

[0004] Although all experiments show that the displacement pressure gradient has a clear effect on the relative permeability curve, there is no method to characterize this effect

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