天津市塘沽低温热储回灌的水-岩相互作用地球化学模拟

地球化学模拟是了解早期阶段回灌影响的有效方法，对塘沽热田的地热回灌试验进行了地球化学模拟，以地热供暖尾水作为初始反应流体，通过模拟其与储层岩石的水－岩相互作用，确定回灌对储层性质的影响，模拟是根据回灌水在不同温度下分别与岩石反应及在不断升温过程中连续与岩石相互作用而进行的，结果表明，回灌的影响在开始阶段是相当重要的，在仅考虑溶解和沉淀矿物间体积平衡的情况下，回灌对储层的孔隙度产生正的效应，水－岩相

MODELING WATER_ROCK INTERACTION OF GEOTHERMAL REINJECTION IN THE TANGGU LOW-TEMPERATURE FIELD, TIANJIN

Geothermal reinjection is carried out in the Tanggu geothermal field. The geochemical modeling is the approach that can be used to understand the early stage effects of reinjection on reservoir properties. Water_rock interaction modeling has taken into consideration the reactions of the reinjected water with the reservior rock under different temperatures and its continuous reactions with the rock during the elevation of the temperature respectively. The results show that reinjection has a positive effect on the reservoir porosity on account of the volumetric balance of dissolution of the rock and the precipitation of secondary minerals. The effect is important at the beginning of reinjection. The secondary minerals assemblage formed by water_rock interaction consists of chalcedony, calcite, muscovite, kaolinite and clinochloee. The composition of the reinjection water tends to be the same as that of geothermal water in reservoir.