东丽湖外源水回灌对碳酸盐岩储层的影响研究

Study on the effect of exogenous water reinjection of Donglihu on carbonate reservoirs

中文关键词: 东丽湖地区  外源水回灌  碳酸盐岩  水-岩反应  Phreeqc程序

英文关键词: Donglihu area  exogenous water reinjection  carbonate rocks  water-rock reactions  Phreeqc

中文摘要:

      地热回灌是维持热储压力的有效手段，针对碳酸盐岩热储回灌效果好的特点，外源水回灌是值得尝试的 方案。本文以东丽湖地区雾迷山组热储为研究对象，根据高温高压水-岩反应实验结果，深入探讨了外源 水回灌对储层的地球化学影响。实验结果表明:高浓水作为回灌水源虽然成本较低，但回灌过程中出现 了钾长石、方解石和伊利石的沉淀，且沉淀量是参与反应岩屑的 1.30%，这可能对储层结构有影响；而采用 混合水作为水源时，回灌过程中生成的新矿物主要以颗粒状附着于白云石或者石英颗粒表面，仅为储层 质量的 0.06%~0.09%，对储层结构的影响微乎其微。综合地球化学因素，笔者认为利用外源水回灌至本地 区雾迷山组碳酸盐岩热储是可行的。同时，从成本效益角度出发，建议优先采用地热尾水和处理后湖水 的混合水进行回灌。

英文摘要:

      Geothermal reinjection is an effective means to maintain the pressure of thermal reservoirs. In viewof the good reinjection effect of carbonate rock thermal reservoirs, external water reinjection is a scheme worth try-ing. This paper takes the thermal reservoir of Wumishan Formation in Donglihu area as the research object. Basedon the experimental results of high-temperature and high-pressure water-rock reaction, it deeply explores the geo-chemical influence of external water recharge on the reservoir. The experimental results show that although the cost of high-concentration water as the reinjection water source is relatively low, the precipitation of potassium feldspar,calcite and illite occurs during the reinjection process, and the precipitation amount is 1.30% of the rock debris in-volved in the reaction. This may have an impact on the reservoir structure. When mixed water is used as the watersource, the new minerals generated during the reinjection process mainly adhere to the surface of dolomite or quartzparticles in granular form, accounting for only 0.06% to 0.09% of the reservoir mass, and have a negligible impacton the reservoir structure. Taking into account the geochemical factors comprehensively, we believe that it is fea-sible to reinject exogenous water into the carbonate rock thermal reservoirs of the Wumishan Formation in this area.Meanwhile, from the perspective of cost-effectiveness, it is recommended to give priority to using the mixed water ofgeothermal tail water and treated lake water for reinjection.