A method and device for constructing a digital core

Abstract

An embodiments of the application disclose a method and a device for constructing a digital core. The method comprises the following steps: carrying out computer tomography (CT) on a core sample to obtain a three-dimensional CT grayscale image of the core sample, wherein the three-dimensional CT grayscale image comprises two-dimensional CT grayscale images corresponding to the designated areas onthe surface of the core sample; scanning the designated areas by using a scanning electron microscope to obtain two-dimensional scanning electron microscope pictures; determining porosities corresponding to the designated pixel points in the two-dimensional CT grayscale images according to the two-dimensional scanning electron microscope pictures; testing the designated areas by using an electronprobe so as to obtain mineral types corresponding to the designated pixel points in the two-dimensional CT grayscale images; determining a corresponding relation between the porosities and a grayscaledistribution range; determining porosities of pixel points in the three-dimensional CT grayscale image, and constructing the four-dimensional digital core of a target area based on the porosities ofthe pixel points in the three-dimensional CT grayscale image. After the technical scheme provided by the embodiments of the application is adopted, the accuracy of the determined digital core can be improved.

Description

technical field [0001] The present application relates to the technical field of logging petrophysical analysis in petroleum exploration, in particular to a method and device for constructing digital cores. Background technique [0002] In the process of petroleum exploration, one of the key tasks of logging interpretation is to accurately calculate the saturation of oil-gas-bearing layers, and when calculating the saturation of oil-gas-bearing layers, it is necessary to determine the saturation index corresponding to the saturation of oil-gas-bearing layers. At present, it is usually necessary to conduct displacement experiments in the laboratory to determine the saturation index. The displacement experiment is to simulate the process of oil and gas displacing water in the early stage of rock accumulation, and to analyze and determine the saturation index by observing the resistivity at different oil saturations. [0003] However, for ultra-low porosity and permeability san...

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Problems solved by technology

However, since the pore size of tight sandstone is mainly at the nanometer level, which generally accounts for 70 percent (%) or even higher of the total pores, the pore framework obtained by the above-mentioned binarization process in the three-dimensional micro-CT grayscale image There are often no connected pore clusters in the core sample, that is, there is no connected channel from one end face of the core sample to the other end face, so that the resistivity value of the subsequent simulation is infinite, or there is an order of magnitude error with the actual situation

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