ISSN 1000-3665 CN 11-2202/P

    渗透率对干热岩开采过程储层变化规律的影响

    Influence of permeability on reservoir change during dry hot rock mining

      摘要
    • 摘要: 热储层由基质系统和裂隙系统共同构成，二者热量传递的方式存在很大区别。仅考虑基质渗透率或裂隙渗透率，与实际采热过程并不相符。只有明确基质-裂隙双重渗透率下热储层的变化规律，才能更为合理、有效地开发地热资源。因此以青海共和盆地地热田GR1井为研究对象，基于热流固耦合理论，运用COMSOL数值模拟软件，建立双重孔隙介质渗透率水流传热模型。通过考虑不同基质渗透率(0，1×10-18，1×10-16 m2)、裂隙渗透率(5×10-11, 1×10-10，2×10-10 m2)，得到了储层温度场、应变场、应力场、位移场变化规律。研究发现：(1)仅考虑裂隙渗透率，会高估储层的开采寿命和产出温度；会低估采热过程中储层产生的压应变和沉降量，表明基质渗透率不能忽略。(2)最优裂隙渗透率为1×10-10 m2，此时最适宜进行热开采；裂隙渗透率为2×10-10 m2，储层寿命低于50 a。(3)采热初期，相比裂隙渗透率5×10-11 m2时的最大压应变，裂隙渗透率为2×10-10 m2时最大压应变提高了2.74倍；采热40 a，相比裂隙渗透率为5×10-11 m2，裂隙渗透率为2×10-10 m2时，储层沉降量增加0.164 05 m，沉降区域扩大3倍左右。所得结论对青海共和盆地干热岩开采过程中渗透率与储层变化规律的研究提供了一定参考。

       

      Abstract: A thermal reservoir consists of a matrix system and a fracture system. There is a big difference in the way of heat transfer between the two systems. Considering only the matrix permeability or the fracture permeability is not consistent with the actual heat recovery process. It is only by clearing the law of the change in the geothermal reservoir under the double permeability of the fracture-matrix that the geothermal resources are developed more reasonably and effectively. The GR1 well in the geothermal field of the Gonghe Basin in Qinghai is taken as the research object. Based on the thermal fluid-solid coupling theory, the COMSOL numerical simulation software is used to establish the dual-porosity medium permeability heat transfer model. The changes in reservoir temperature field, strain field, stress field and displacement field are obtained by considering different matrix permeability (0, 1×10-18, 1×10-16 m2) and fracture permeability (5×10-11, 1×10-10, 2×10-10 m2). The results indicate that (1) when only considering the fracture permeability, the reservoir production life and output temperature will be overestimated; the compressive strain and settlement of the reservoir during the heat recovery process will be underestimated, indicating that the matrix permeability cannot be ignored. (2) The optimal fracture permeability is 1×10-10 m2, which is most suitable for thermal mining. The fracture permeability is 2×10-10 m2 and the reservoir life is less than 50 a. (3) At the initial stage of heat recovery, the maximum compressive strain increases by 2.74 times with the permeability of 2×10-10 m2 compared with the fracture permeability of 1×10-10 m2. When heating 40 a, compared with the permeability of 5×10-11 m2, when the fracture permeability is 2×10-10 m2, the reservoir settlement increases by 0.164 05 m, and the settlement area is expanded by about 3 times. The conclusions obtained provide a reference for the study of permeability and reservoir variation in the dry hot rock mining process in the Gonghe Basin in Qinghai.

       

      • HTML全文
      • 参考文献(24)
      • 相关文章
      • 施引文献
    • 资源附件(0)

    /

    返回文章
    返回

    邮件订阅

    RSS