碳酸盐岩热储对湖水回灌的响应  

GEOCHEMICAL RESPONSES OF CARBONATE RESERVOIR TO UNTREATED LAKE WATER REINJECTION

作　　者：刘东林[1] 李义曼[2] 庞忠和[2,3] 赵苏民 范翼帆[2,3] LIU Donglin;LI Yiman;PANG Zhonghe;ZHAO Sumin;FAN Yifan(Tianjin Geothermal Exploration and Development-Designing Institute, Tianjin 300250;Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing 100029;University of Chinese Academy of Sciences, Beijing 100049)

机构地区：[1]天津地热勘查开发设计院,天津300250 [2]中国科学院地质与地球物理研究所,北京100029 [3]中国科学院大学,北京100049

出　　处：《工程地质学报》2019年第1期178-183,共6页Journal of Engineering Geology

基　　金：东丽湖地表水蓟县系雾迷山组热储回灌工程项目(国土房任[2014]25号)资助~~

摘　　要：回灌式开采是目前普遍提倡的保持热储压力、减缓水位下降、实现地热资源可持续开发利用的有效手段之一。外源水回灌是近年来探讨的新思路,是易于回灌的碳酸盐岩储层的优选方案。本文针对天津东丽湖地区蓟县系雾迷山组白云岩热储,通过开展储层条件下水-岩相互作用实验,探讨了未处理湖水回灌的可行性和热储层的地球化学响应。结果表明,未经处理湖水回灌后,其TDS显著降低,说明发生了沉淀,经计算沉淀量为142. 6 mg·L-1,相当于矿物质量增加了0. 09%。反应初期阶段,斜长石发生溶解,释放出K、Ca、Na等碱金属和Si O2等组分;导致溶液中白云石、方解石和钾长石过饱和而沉淀析出;随着反应进行,不全等溶解沉淀作用使部分白云石发生溶解,而方解石持续沉淀;伊利石是反应过程中形成的主要黏土矿物,其对储层结构的影响取决于其形状。基于现有实验结果,认为未处理湖水直接回灌对白云岩热储的影响较小,不会破坏储层结构。Exploitation with reinjection is thought to be one of the most effective ways to keep reservoir pressure and mitigate water table decrease, which it s widely encouraged. Reinjection with water from other sources is proposed for carbonate reservoir that is easily to inject. This paper discusses the possibility of reinjection with untreated lake water and geochemical responses of carbonate reservoir based on water-rock interactions experiments for dolomite reservoir of Wumishan Group in Donglihu Area, Tianjin. Results show that after reactions with dolomite, TDS of reacted water decreases indicating that precipitation occurs and the precipitates amounts to 142.6mg·L^-1 ,which is equal to 0.09%increase in mineral quality. At the initial stage, plagioclase dissolves and alkaline metals like K、Ca、Na, SiO2 and Al-bearing compositions were released, leading to oversaturation and precipitations of dolomite, calcite and K-feldspar. With the progresses of reactions, incongruent dissolution causes part of the dolomite dissolves while calcite keeps precipitating. Illite precipitates and its effects on reservoir structure depend on its shape. Based on the experimental data, it s concluded that the dolomite reservoir will slightly be affected by reinjection of lake water and it s still a good way to explore sustainable developments for geothermal exploitation.

关 键 词：碳酸盐岩 湖水回灌 地球化学响应 雾迷山组 白云岩 

分 类 号：P314[天文地球—固体地球物理学]