Method for analyzing pore characterization of tight sandstone reservoir based on Matlab

Abstract

The invention discloses a method for analyzing pore characterization of a tight sandstone reservoir based on Matlab, and the method is as follows: firstly reading a cast thin slice image and an SEM image of the tight sandstone reservoir; then adjusting an image threshold, and performing binarization processing on the cast thin slice image and the SEM image to obtain a binary image; calculating porosity by identifying black pixel points of the binary image; and obtaining pore radius distribution of the tight sandstone reservoir; finally, the obtaining the pore average diameter and the varianceof the tight sandstone reservoir, and the outputting the obtained binary image and obtained data. Researches on the pore characterization of the tight sandstone reservoir by use of the software Matlabare mainly divided into two methods. One method uses a built-in function to quantitatively analyze the binary image, and is suitable for nano-scale pores and micro-scale pores. The other method useslinecut or a slice method to directly analyze the cast thin piece and SEM image and the like, and is suitable for nano-scale pores.

Description

technical field [0001] The invention relates to the technical field of pore characterization analysis of tight sandstone reservoirs, in particular to a method for analyzing the pore characterization of tight sandstone reservoirs based on Matlab. Background technique [0002] Reservoir microscopic pore structure refers to the geometric shape, size, distribution and interconnection of pores and channels in reservoir rocks, which directly affects the development of reservoir pore space. Reservoir storage space is divided into three levels: millimeter pores, micropores, and nanopores. Cai Cai and others discovered nanopores for the first time in the study of unconventional reservoirs in China by applying field emission scanning electron microscopy and nano-CT reconstruction technology. Famous scholars have studied the pore structure and characterization of tight sandstone reservoirs, and various methods have been applied to study the pores of tight sandstones, mainly in three ca...

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Problems solved by technology

Fluid injection experiments represented by mercury porosimetry can indirectly obtain parameters such as reservoir space distribution and pore size through mercury intrusion curves, but cannot directly observe reservoirs like image observation methods such as SEM and nano-CT technology. Spatial distribution, pore throat characteristics and other characteristics

[0004] However, guided by scanning electron microscopy and nano-CT, most of the research results are qualitative descriptions of the geometry and connectivity of pore throats, and quantitative research on pore characterization is still insufficient.

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