Method for evaluating sealing properties of cap rocks in carbon dioxide flooding storage

Abstract

The invention discloses a method for evaluating sealing properties of cap rocks in carbon dioxide flooding storage, and belongs to the field of a carbon dioxide flooding process. The method is characterized by comprising the following steps of 1) building a carbon dioxide geological storage body well log response model; 2) determining a regional cap rock, a direct cap rock and an interlayer in a reservoir; 3) compiling a cap rock plane distribution chart, and determining cap rock player plane distribution feature parameters; 4) calculating a seepage velocity of carbon dioxide of each phase state in the cap rocks, and establishing percolation comprehensive evaluation parameters; 5) building a porosity and displacement pressure fitting model and a permeability and throat feature parameter fitting model; 6) performing numerical simulation on a reaction process of different chemical substances in the cap rocks, and determining erosion resistance of different cap rocks; and 7) establishing evaluation indexes for the seal properties of the cap rocks in the carbon dioxide flooding storage of an oil field, thereby performing comprehensive evaluation on the sealing abilities of the cap rocks. According to the method, multi-factor stereoscopic comprehensive evaluation is performed for the cap rocks, so that the precision of evaluating the sealing abilities of the cap rocks is greatly improved.

Description

technical field [0001] The invention belongs to the technical field of carbon dioxide flooding, and in particular relates to a method for evaluating the sealability of cap rocks in carbon dioxide flooding and sequestration. Background technique [0002] Up to now, the sealing performance evaluation of cap rocks in carbon dioxide flooding and sequestration of ultra-low permeability reservoirs in China is still insufficient. Only the escape of free phase carbon dioxide is considered, and the research on the escape of diffuse phase and water-soluble phase carbon dioxide is less and not deep enough. Throats are the key factors affecting the microscopic seepage of ultra-low permeability reservoirs and cap rocks. However, the current research only stays at the level of pore analysis, without distinguishing pores from throats. influences. Contents of the invention [0003] The present invention aims to solve the above problems, and provides a method for evaluating the sealabilit...

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Problems solved by technology

[0002] Up to now, the sealing performance evaluation of cap rocks in carbon dioxide flooding and sequestration of ultra-low permeability reservoirs in China is still insufficient. Only the escape of free phase carbon dioxide is considered, and there are few and in-depth studies on the escape of diffuse phase and water-soluble phase carbon dioxide.

Throats are the key factors affecting the microscopic seepage of ultra-low permeability reservoirs and cap rocks. However, the current research only stays at the level of pore analysis, without distinguishing pores from throats. influences

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