Carbonate rock pore structure classification method based on overburden pressure seepage experiment

Abstract

The invention relates to the field of reservoir rock pore structure classification in the oil and gas field development process, in particular to a carbonate rock pore structure classification methodbased on an overburden pressure seepage experiment, which comprises the following steps: preparing a rock sample, and measuring the gas permeability of the rock sample; after the rock sample is saturated with simulated oil, performing a permeability-confining pressure relation determination experiment, and obtaining a permeability-confining pressure curve; carrying out piecewise fitting on the permeability-confining pressure curve to obtain a permeability-confining pressure fitting curve, and analyzing a parameter change rate of piecewise fitting; observing the rock core, and preliminarily judging the pore structure type according to the rock core observation result; according to the difference of the change rates of the fitting parameters of different segments, classifying the pore structure type of the rock core by combining the rock core observation result and the theoretical analysis of the permeability-confining pressure fitting curve characteristics, and the pore structure classification result of the classification method is closer to the real situation of the carbonate reservoir.

Description

technical field [0001] The invention relates to the field of pore structure classification of reservoir rocks during the development of oil and gas fields, in particular to a method for classifying the pore structure of carbonate rocks based on overburden seepage experiments. Background technique [0002] There are many methods for characterization and classification of rock pore structure, such as mercury injection, casting thin section, nuclear magnetic resonance and other methods can be used to study and classify rock pore structure, but the classification of rock pore structure by these methods is only the result of static analysis and evaluation , does not reflect the pore structure and its dynamic change characteristics under actual formation conditions, especially in carbonate reservoirs, where fractures are developed and the pressure is generally high. The dynamic evaluation method is needed to classify the pore structure types. Contents of the invention [0003] ...

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Problems solved by technology

[0002] There are many methods for characterization and classification of rock pore structure, such as mercury injection, casting thin section, nuclear magnetic resonance and other methods can be used to study and classify rock pore structure, but the classification of rock pore structure by these methods is only the result of static analysis and evaluation , does not reflect the pore structure and its dynamic change characteristics under actual formation conditions, especially in carbonate reservoirs, where fractures are developed and the pressure is generally high. constantly changing, it is necessary to use dynamic evaluation methods to classify its pore structure types

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