摘要
化学刺激能够改善增强型地热系统(EGS)热储层裂隙连通情况、提高裂隙渗透率。本文以EGS热储化学刺激为出发点,开展土酸体系-花岗岩作用实验,总结实验规律,明确了酸岩作用机理,建立多矿物耦合反应动力学模型并获取重要参数。得出以下结论:土酸中HF浓度越高,对花岗岩的溶蚀率和溶蚀速率就越大,但更易产生二次沉淀;酸液中离子的浓度与不同矿物溶蚀存在对应关系,Na+和K+分别来自于钠长石和伊利石,Al3+和硅来自长石类和黏土类矿物,Ca2+前期来自方解石,后期受钙长石和氟石影响;土酸-花岗岩反应为双重机制控制下的动力学反应;HF机制下的矿物溶解反应速率常数数量级约为10-4~10-5,比中性机制下的矿物的溶解速率提高了约9个数量级。研究结果可以为EGS储层化学刺激工作提供理论支持。
Chemical stimulation can improve the fracture connectivity and permeability of an EGS reservoir.Experiments were carried out on the interaction of RMA(regular mud acid)with granite.The mechanism of acid rock action was clarified,and the dynamic model of multi-mineral reactions was established.Higher the HF concentration in the RMA,higher is the dissolution rate of the granite,but secondary precipitation is more likely to occur.Na+and K+come from feldspar and illite,Al3+and silicon from feldspar and clay minerals,Ca2+comes from calcite in the early stage,and is influenced by calcium-feldspar and fluorite in later stages.The reaction is a dynamic reaction under dual mechanism control.The order of magnitude of the mineral dissolution rate constant under the HF mechanism is approximately 10-4~10-5,which is increased by about 9 orders of magnitude compared to that of minerals under neutral mechanisms.The results can provide theoretical support for chemical stimulation of the EGS reservoir.
作者
岳高凡
李晓媛
甘浩男
王贵玲
YUE Gaofan;LI Xiaoyuan;GAN Haonan;WANG Guiling(Institute of Hydrogeology and Environmental Geology,Chinese Academy of Geological Sciences,Shijiahzuang,050060;Technology Innovation Center of Geothermal&Hot Dry Rock Exploration and Development,Ministry of Natural Resources,Shijiahzuang,050060)
出处
《地质学报》
EI
CAS
CSCD
北大核心
2020年第7期2107-2114,共8页
Acta Geologica Sinica
基金
国家自然科学基金青年基金项目(编号41807208)
国家重点研发计划(编号2018YFB1501800)
中国地质调查局地质调查项目(编号DD20190555)共同资助成果。
关键词
增强型地热系统
化学刺激
水岩作用实验
反应动力学
渗透率改造
enhanced geothermal systems
chemical stimulation
acid-rock interaction
multi-mineral reaction kinetics
permeability modification
