考虑压溶作用的THCM耦合模型研究

压溶作用在岩石孔隙和裂隙的演化中具有重要的作用，而岩石的孔隙和裂隙对CO2的封存和运移又起着决定性的作用。本文在多场耦合数值模拟程序TOUGHREACT-FLAC3D的基础上增加的考虑压溶作用的模块，并通过建立一维实验室尺度理论模型，探究压溶作用对CO2封存的影响。本文基于压溶作用，建立了石灰岩THCM耦合作用模型，研究发现：在CO2存在的条件下，压溶作用能够促进岩石孔隙率的变化，并且压溶对孔隙率的修正作用占孔隙率的总变化量的20%左右；力学方面，压溶作用使岩石应变速率增加10%左右；在矿物演变方面，钙离子浓度增加1/1000左右，矿物含量降低1/1000左右。本文创新点：在原有耦合计算模块上，添加了考虑压溶作用计算模块；在前人工作基础上进行了合理的有效的模拟实验并得出定量的结论。

RESEARCH OF THE THCM COUPLING MODEING THEL CONSIDER PRESSURE SOLUTION

Pressure solution plays an important role in the evolution of rock pores and fractures. The porosity and fissure of rock play a decisive role in CO2 storage and migration. In this paper, based on the multifield coupled numerical simulation program TOUGHREACT-FLAC3D,an additional module considering pressure solution is added. And the theoretical model of one-dimensional laboratory scale is established to explore the effect of pressure solution on CO2 sequestration. This paper is based on pressure-solubilization. The coupling model of limestone THCM is established. The study found that:In the presence of CO2,Pressure solubilization can promote the change of rock porosity, and the effect of pressure solution on porosity is about 20% of the total change of porosity. In mechanics, pressure solution increases the strain rate of rock by about 10%.In terms of mineral evolution, the concentration of calcium increases by about 1/1000,The mineral content is reduced by about 1/1000. The innovation of this paper is on the original coupling calculation module. The calculation module considering pressure solution is added. Based on the previous work, a reasonable and effective simulation experiment is carried out and a quantitative conclusion is drawn.