In geothermal reservoir exploitation, the thermal conductivity of casing cement material is a key parameter that may affect the heat exchange and utilization efficiency of geothermal reservoirs. Based on a systematic approach of theoretical analysis, experimental research and microscopic analysis, this paper presents graphite composite cement (GC) with high thermal conductivity for potential application in geothermal reservoir exploitation. The GC consists of ordinary Portland cement (P.O 42.5), natural flake graphite, water-reducing agent (GB), early strength agent (CaCl₂) and defoamer (HB-03). The physical properties of the GC, such as fluidity, pumpability, setting time, compressive strength and thermal conductivity, were obtained by carefully prepared laboratory tests that met our expectation. Finally, X-ray diffractometry and environmental scanning electron microscopy were used to analyze the micro-characteristics for an interpreted thermal conduction mechanism of GC. The results of analyses show that the formation of thermal conductivity network of natural flake graphite in cement is a key to improve thermal conductivity. The research results provide a new solution to the problems of low thermal energy extraction efficiency and poor cementing quality of geothermal reservoirs.

中文翻译：

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用于地热开采的高导热水泥

在地热油藏开发中，套管水泥材料的导热系数是可能影响地热油藏热交换和利用效率的关键参数。基于理论分析，实验研究和微观分析的系统方法，本文提出了具有高导热率的石墨复合水泥（GC）在地热油藏开发中的潜在应用。GC由普通波特兰水泥（PO 42.5），天然鳞片石墨，减水剂（GB），早期强度剂（CaCl ₂）和消泡剂（HB-03）。GC的物理性质，例如流动性，可泵送性，凝结时间，抗压强度和导热系数，是通过精心准备的符合我们期望的实验室测试获得的。最后，使用X射线衍射仪和环境扫描电子显微镜分析了GC解释的热传导机理的微观特征。分析结果表明，水泥中天然片状石墨导热网络的形成是提高导热系数的关键。该研究结果为地热储层热能提取效率低，固井质量差的问题提供了新的解决方案。