化学刺激技术在干热岩储层改造中的应用与最新进展  

Application and Recent Progresses of Chemical Stimulation on Hot Dry Rock Reservoir Modification

作　　者：冯波[1] 许佳男 许天福[1] 李胜涛[1,2] 宋丹[1] 陈明涛[1] FENG Bo;XU Jia-nan;XU Tian-fu;LI Sheng-tao;SONG Dan;CHEN Ming-tao(Key Laboratory of Groundwater Resources and Environment of Ministry of Education,Jilin University,Changchun 130021,Jilin,China;Center for Hydrogeology and Environmental Geology Survey,China Geological Survey,Baoding 071051,Hebei,China)

机构地区：[1]吉林大学地下水资源与环境教育部重点实验室,吉林长春130021 [2]中国地质调查局水文地质环境地质调查中心,河北保定071051

出　　处：《地球科学与环境学报》2019年第5期577-591,共15页Journal of Earth Sciences and Environment

基　　金：国家重点研发计划项目(2018YFB1501802);吉林省教育厅项目(JJKH20170807KJ);中国地质调查局地质调查项目(DD20190127);中国地质科学院基本科研业务费专项资金项目(YK201611)

摘　　要：干热岩是一种没有水(或含有少量水而不流动)的高温(>180℃)岩体,多为变质岩或花岗岩,岩性致密,很少存在孔隙或裂隙,渗透性极差。增强型地热系统(Enhanced Geothermal System,EGS)是利用水力压裂、化学刺激等措施形成人工地热储层,通过注入载热流体从低渗透性干热岩中经济有效地开采出热能的人工地热开采系统,是开发干热岩型地热资源的有效方法。增强型地热系统成功的关键在于可控性良好的储层改造手段,化学刺激即为储层改造常用的方法之一。通过回顾国内外有关增强型地热系统储层改造中化学刺激技术研究的最新成果,总结了实际应用化学刺激技术的增强型地热系统工程经验。结果表明:增强型地热系统中采用的化学刺激剂多数为酸性化学刺激剂,其中螯合酸具有阻垢性、缓速性、催化性、二次沉淀少、腐蚀性弱等优点,能够实现深穿透、低伤害的储层激发;单一的碱性化学刺激剂(NaOH和Na 2CO 3)的室内实验结果较为理想,但是场地应用效果并不令人满意,添加了NTA、EDTA等螯合剂的碱性化学刺激剂可减少次生沉淀的生成,从而取得良好的储层改造效果。最后,针对青海共和盆地正在开展的干热岩开发示范工程项目,提出热刺激和碱性化学刺激联合的储层刺激工艺,该工艺有可能在深部高温岩体中产生改造体积更大的地热储层,提高储层改造的效果。Hot dry rock(HDR)is a kind of high temperature(>180℃)rock without water(or with little water and cannot flow),and with low porosity and permeability,which is mostly composed of metamorphic rock or granite.Enhanced geothermal system(EGS)is an effective method for exploiting HDR geothermal resources.Artificial geothermal reservoir has been created to extract economical amounts of heat from low permeability geothermal resources by hydraulic fracturing or chemical stimulation,which is important for the exploitation of geothermal energy.As a consequence,chemical stimulation,in addition to hydraulic and thermal fracturing,is proposed and employed as an important method for the reservoir modification.The latest researches on chemical stimulation technology in EGS reservoir modification were reviewed,and the EGS engineering experience using chemical stimulation technology of practical application was summarized.The results show that most of the chemical stimulation used in EGS are acid chemical stimulation,especially the chelating acid has the advantages of scale inhibition,slowness,catalytic performance,less secondary precipitation,and weak corrosiveness,which can achieve deep penetration and low damage to reservoir excitation;alkaline chemical stimulation(NaOH and Na 2CO 3)laboratory experimental results are good,but the effect of practical application is not good,and the addition of alkaline stimulants,such as NTA,EDTA and other chelating agents,can reduce the formation of secondary precipitation and obtain good reservoir modification effect.Finally,a reservoir modification process combined with thermal stimulation and alkaline chemical stimulation for HDR development demonstration project being carried out in Gonghe Basin of Qinghai was proposed,this process may produce geothermal reservoir with larger volume and improve the effect of reservoir reconstruction.

关 键 词：干热岩 增强型地热系统 化学刺激 储层改造 酸性 碱性 螯合剂 渗透性 

分 类 号：P314[天文地球—固体地球物理学] TK521[天文地球—地球物理学]