THM耦合条件下CO_(2)地质封存注入方案优化研究  

RESEARCH ON OPTIMIZATION OF C_(2)INJECTION SCHEME UNDER THM COUPLINGS IN C_(2)GEOLOGICAL STORAGE

作　　者：龚耕 李毅[1,2] 唐栋 喻浩 蒋中明[1] GONG Geng;LI Yi;TANG Dong;YU Hao;JIANG Zhongming(School of Hydraulic and Environmental Engineering,Changsha University of Science and Technology,Changsha 410114,China;Key Laboratory of Water-Sediment Sciences and Water Disaster Prevention of Hunan Province,Changsha 410114,China)

机构地区：[1]长沙理工大学,水利与环境工程学院,长沙410114 [2]长沙理工大学,水沙科学与水灾害防治湖南省重点实验室,长沙410114

出　　处：《工程地质学报》2023年第3期1084-1096,共13页Journal of Engineering Geology

基　　金：湖南省教育厅科学研究重点项目(资助号:22A0218);湖南省自然科学基金项目(资助号:2023JJ30027);国家自然科学基金(资助号:52179095)。

摘　　要：我国首个GCS示范工程神华多储层场地出现了单储层吸气量剧增的现象,在其原设计方案下,压缩后变冷的CO_(2)被注入至深部高温含水层中,引起首层含水层中流体压力和温度应力急剧变化,从而导致大量裂隙产生,增加了单储层的可注入性的同时,降低了系统总体封存能力,并带来了泄露风险。本文基于TOUGH-FLAC三维多相多组分THM耦合数值模拟程序,开发了场地尺度岩体开裂模块来研究CO_(2)注入方案对目标含水层耦合特性和开裂特性的综合影响,并设计了定速率、先增速后定速、间歇定速、间歇变速、二次变速等多类型注入方案,分别计算分析了储层岩体的热力学特性、多相流特性与开裂情况。结果表明:设计方案下含水层产生了较多的开裂现象,是导致其可注入性增大的根本原因,持续注入CO_(2)引起含水层岩体中有效应力大幅度降低,渗透率增加,定速率方案产生的温度应力最小,在设计各类注入方案中,定速率注入方案下储层的裂缝发育最少。Shenhua multi-layered reservoir is the first GCS demonstration project in China.The gas absorption of its single reservoir increased dramatically.Under the original designed scheme,the cooled CO_(2)after compression was injected into the deep high-temperature aquifer,resulting in a sharp change in the fluid pressure,thermal stress and a large number of fractures in the first aquifer.The injectivity of the first layer was increased,but the storage capacity of the whole system was reduced,and it also brought the risk of leakage.A site-scale rock mass cracking module was developed,based on the TOUGH-FLAC,a three-dimensional multiphase multi-component THM coupling numerical simulation program,to study the comprehensive effect of CO_(2)injection scheme on the coupling characteristics and cracking characteristics of the target aquifer.Injection schemes including constant rate,first growth rate and then constant rate,intermittent constant rate,intermittent variable rate and secondary variable rate were designed,and the thermodynamic characteristics,multiphase flow characteristics and cracking of reservoir rock mass were calculated and analyzed.The results show that there are many cracks observed in the aquifer under the original designed scheme,and it is the reason of the injectivity increase.Continuous injection of CO_(2)causes a significant decrease in the effective stress in the aquifer rock mass and an increase in the permeability.The thermal stress under the constant rate scheme is the smallest.Among the designed injection schemes,the fracture observed in the reservoir under the constant rate injection scheme is the least.

关 键 词：THM耦合 GSC 二氧化碳地质封存 数值模拟 开裂 

分 类 号：P642.5[天文地球—工程地质学]