Shale reservoir permeability prediction method based on improved kozeny-carman model

Abstract

The invention discloses a shale reservoir permeability prediction method based on the improved Kozeny-Carman model, which corrects the shale reservoir pore cross section from non-circular pores to circular pores; uses the pore equivalent diameter to quantitatively characterize the pore size evolution ; Determine the pore size fractal factor based on the fractal coarsening theory; calculate the capillary length and the number of pores in the preset range according to the pore size fractal factor, calculate the pore volume by using the real-time pore equivalent radius and the capillary length, and use the capillary length and the preset range The matrix volume is calculated by the number of pores, the dynamic porosity is calculated by using the pore volume and the matrix volume, and the apparent permeability of a single capillary of different sections is calculated by using the real-time equivalent pore radius. Permeability calculates the apparent permeability of shale. The invention comprehensively considers the characteristics of the shale reservoir, dynamically characterizes the porosity of the shale reservoir based on the fractal theory, and applies the dynamic porosity to the quantitative characterization of the permeability of the shale reservoir.

Description

technical field [0001] The technical field of the invention is the theoretical calculation field of shale reservoir permeability in unconventional oil and gas development, and specifically relates to a shale reservoir permeability prediction method based on an improved Kozeny-Carman model. Background technique [0002] As a new type of unconventional natural gas resource, shale gas is attracting increasing attention and attention due to its wide distribution and large amount of resources. How to develop this kind of unconventional energy scientifically and efficiently needs to start from the characteristics of shale reservoirs, and according to its completely different pore structure, storage mode and other characteristics, establish a corresponding calculation method or model for quantitatively characterizing the physical parameters of the reservoir. As the key basic parameters of reservoir physical properties, permeability and permeability are the basis of reserve calculat...

AI Technical Summary

Problems solved by technology

Although the classical Kozeny-Carman equation established based on equal-diameter circular capillaries has been widely used in the permeability prediction of conventional reservoirs, due to the complex pore structure of shale reservoirs, organic pores, inorganic pores and stress-sensitive slit-shaped pores are common. development and strong microscopic heterogeneity, the classical Kozeny-Carman model used to characterize the relevant physical properties of shale reservoirs has the following problems: 1. The diversity of pore cross-section geometry in shale reservoirs is not considered; 2. Shale reservoirs are not considered Reservoir cross-scale pore structure characteristics; 3. The pore size evolution caused by adsorption and stress sensitivity during the dynamic development process of shale reservoir depressurization is not considered; 4. Mass transfer behaviors such as slip boundary, surface and Knudsen diffusion are not considered

Therefore, the physical parameters of shale reservoirs calculated by using the traditional Kozeny-Carman equation theory deviate greatly from the measured data, which leads to a large deviation in the productivity prediction results

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