基于正交试验的地热固井材料性能评价

Performance Evaluation of Geothermal Cementing Materials Based on Orthogonal Tests

常规地热固井材料导热系数低,会影响地热井取热量及降低能源利用效率。为了提高地热固井材料导热系数,本研究采用正交试验并运用层次分析和极差分析,对地热固井材料各项指标进行综合性能研究。研究表明:石墨、氧化铝和钢渣粉都能有效提高导热系数,石墨提升作用明显,钢渣粉次之,氧化铝最小;综合性能评价中石墨属于显著因素,氧化铝和钢渣粉属于一般因素;随着石墨掺量的增加,导热系数逐渐升高,8 h抗压强度和流动度降低。高导热固井材料最佳配比为:7%石墨、1%氧化铝黄睿、3%钢渣粉,导热系数为1.604 W/(m·K),比常规固井材料0.9059 W/(m·K)的导热系数提高了约77%。

The low thermal conductivity of geothermal cementing materials affects the heat extraction of geothermal cementing and reduces the energy utilization efficiency.In order to improve the thermal conductivity of geothermal cementing materials,orthogonal tests together with hierarchical analysis and extreme difference analysis were used to investigate the comprehensive performance of geothermal cementing materials.The results show that graphite,alumina and steel slag powder can effectively improve the thermal conductivity,with graphite having a significant improvement,steel slag powder being the second and alumina the smallest.In the comprehensive performance evaluation,graphite is a significant factor,and alumina and steel slag powder are general factors.With the increase of graphite dosing,the thermal conductivity gradually increased,the 8h compressive strength and flowability decreased.The best ratio of high thermal conductivity cementing material was 7%graphite,1%alumina and 3%steel slag powder,and the thermal conductivity was 1.604 W/(m·K),which was about 77%higher than the thermal conductivity of 0.9059 W/(m·K)in the control group.