热储特征对砂岩热储采灌井距的影响

水热型地热资源的回灌式开采是公认的地热可持续开采方式，而采灌井距是地热项目中需要着重关注的问题，以避免开采井中的热突破现象。回灌水在热储中的运移取决于热储特征，也就是储层的透水能力，主要指热储的孔隙度、渗透率及砂泥岩组合关系等参数。基于济阳坳陷典型地热田的储层数据，采用Tough2为核心的Petrasim软件建立数值模型，系统研究了储层孔隙度、渗透率及单砂体厚度对热储中回灌水的运移以及温度场的影响。模拟结果显示：（1）储层孔隙度对回灌压力与采灌井距几乎没有影响；（2）储层渗透率对采灌率和采灌压力影响较大，控制着热储的回灌能力，但对采灌井距没有影响；（3）多次叠置的薄砂层热储中的泥岩隔层影响回灌水运移，在多层薄砂叠置的热储中回灌水水平运移距离远，温度影响范围更大，应扩大采灌井距。该研究对地热开发项目的可持续运行具有指导意义。

Impact of reservoir characteristics on the well spacing of sandstone geothermal reservoir: A case study of Jiyang Depression

The reinjection exploitation of hydrothermal resources is a recognized method of sustainable exploitation. The well space between the production and reinjection well is an essential issue because the thermal breakthrough in production well is the main negative impact during reinjection. The migration of reinjection water in the geothermal reservoir depends on the permeability of the reservoir, constrained by the geothermal reservoir characteristics. In this study, A numerical model using the Petrasim software with Tough2, as the core as well as reservoir data of each typical geothermal field in Jiyang depression, was established. The impact of the reservoir porosity and permeability and the thickness of a single sand layer on the migration of reinjection water and temperature field in the geothermal reservoir were analyzed systematically. The simulation results revealed that the reservoir porosity had a minor impact on the reinjection of the geothermal reservoir, including the reinjection pressure and the spacing of production and reinjection wells. The reservoir permeability affected the reinjection pressure, and then controlled the reinjection performance of the geothermal reservoir, while it had no impact on the spacing of production and reinjection wells. The sand layer superposition combination had a minor impact on the reinjection pressure of the geothermal reservoir. The distance of the horizontal migration of reinjection water in the multilayer stacked thin sand layers was longer, and the range of temperature influence was larger. Thus, it is necessary to expand the well space between production and reinjection well. This study is of significance for the stable operation of geothermal development projects.