Method for determination of three-dimensional pore structure of rocks for CO2 water-rock reaction

Abstract

The present invention provides a method for CO 2 A rock three-dimensional pore structure determination method for water-rock reaction, the method comprising: cutting a collected rock columnar sample into a first rock sample and a second rock sample; determining the porosity of the first rock sample before the experiment, and obtaining the Multiple micro-drill samples, determine the volume ratio of each micro-drill sample; determine the porosity of the second rock sample before the experiment; reset each micro-drill sample on the corresponding position of the second rock sample, and place the first rock sample and the second rock sample The rock samples were assembled and packaged; the packaged samples were subjected to CO 2 Water-rock reaction experiment; determine the porosity of the first rock sample after the experiment, determine the porosity of the second rock sample after the experiment; determine the pore change characteristics of the first rock sample, and determine the pore change characteristics of the second rock sample; according to the second rock sample The pore change characteristics of the first rock sample are constrained to determine the pore structure evolution characteristics of the rock columnar sample.

Description

technical field [0001] The invention relates to the field of rock pore structure determination, in particular to a method for CO 2 Method for determination of three-dimensional pore structure of rocks by water-rock reaction. Background technique [0002] With the great development of the global economy today, with CO 2 The impact of greenhouse gases on the environment has attracted global attention, how to effectively carry out CO 2 Reduced emissions, emitted CO 2 How to carry out effective storage and utilization has become an important issue that the government is concerned about. will CO 2 Inject into low porosity and permeability oil layers, on the one hand, reduce CO 2 The impact on the atmosphere, on the other hand, enhances oil recovery, so it has become a storage method that many countries and regions focus on. Supercritical CO 2 The influence on rock pore structure has become a hotspot of research and attention. supercritical CO 2 After entering the reservoi...

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Problems solved by technology

With the increase of Peclet number, the proportion of diffusive transport decreases and the proportion of convective transport increases) and the corresponding relationship between the dissolution intensity, which indicates that the low Peclet number forms surface corrosion, and the medium Peclet High Peclet number forms large-scale dissolution channels, and high Peclet number forms uniform dissolution; then, Garcia-Rios et al. observed and confirmed this understanding through experiments, and Dávila et al. also confirmed that with the increase of Peclet number, the dissolution in rocks However, at the same time, Dávila et al. also pointed out that it is necessary to pay attention to the influence of rock heterogeneity in the research process, and local heterogeneity may have a fundamental impact on the overall dissolution trend.

[0003] However, previous studies on CO 2 When studying the three-dimensional pore structure of rocks before and after the water-rock reaction, the accuracy of the CT scanning used cannot meet the research requirements

CO in the laboratory 2 During water-rock reaction, considering the high-temperature and high-pressure environment, the size of the selected sample is generally large, mainly with a diameter of 2.54cm, and the resolution of CT equipment is directly related to the size of the scanned sample. Therefore, the published data show that CT The scanning resolution is only tens of microns, it is difficult to scan the rock pore structure with high resolution

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