中深层水平连通地热井取热特性研究

Heat Extraction Characteristics of Medium to Deep Horizontally Connected Geothermal Wells

张杰 王贵洋 王鹏涛 王姝媛

ZHANGJie WANGGuiyang WANGPengtao WANGShuyuan

西南石油大学机电工程学院, 四川 成都 610500 西南石油大学地热能研究中心, 四川 成都 610500 中石化绿源地热能(陕西)开发有限公司, 陕西 咸阳 712000 中国石油天然气销售公司, 北京 东城 100007

School of Mechatronic Engineering, Southwest Petroleum University, Chengdu, Sichuan 610500, China Geothermal Energy Research Center, Southwest Petroleum University, Chengdu, Sichuan 610500, China Green Energy Geothermal Development Co. Ltd., SINOPEC, Xianyang, Shaanxi 712000, China Natural Gas Marketing Company, PetroChina, Dongcheng, Beijing 100007, China

高效取热技术是实现地热效益化开发的关键，建立了水平连通地热井数值仿真模型，计算了连续开采和间歇开采工况下的出口流体温度和换热量，研究了注入温度、注入流量、水平段长度对系统换热性能和岩层温度恢复能力的影响。结果表明，随着注入流量增加，地热井出口水温下降，但整个系统换热量提高；当注入温度较高时，可有效提高出口水温，但系统换热量降低较大；随着水平段长度增加，出口水温和换热量逐渐上升，换热性能提高；岩层温度恢复能力随注入流量和注入温度的增加而提高。综合考虑钻井成本、水泵功耗等因素，适量增加注入流量、降低注入温度、增加水平段长度能有效提高水平连通换热井的换热性能；虽然高的注入温度可提升岩层温度恢复能力，但不利于提高系统换热性能。

Efficient heat extraction technology of geothermal well is the key to efficient and sustainable development. A numerical simulation model for horizontally connected geothermal wells has been established. The outlet fluid temperature and heat transfer under continuous and intermittent heat exchange conditions were calculated. Effects of injection temperature, injection flow rate and horizontal section length on the heat transfer performance of the geothermal system and the temperature recovery ability of rock strata were analyzed. The results show that the water temperature at the outlet of the geothermal well decreases with the increasing of injection flow, but heat extraction capacity of the whole system increases. When the injection temperature is high, the outlet water temperature can be effectively increased, but the heat exchange capacity of the system decreases greatly. With the increasing of horizontal section length, the outlet water temperature and heat exchange capacity gradually increase, and the heat transfer performance of geothermal well improves. Rock temperature recovery ability increases with the increasing of injection flow rate and injection temperature. Taking into account factors such as drilling cost and pump power consumption, the heat transfer performance of geothermal well can be effectively improved by appropriately increasing the injection flow, lowering the injection temperature and increasing the horizontal section length. Although increasing the injection temperature can improve the temperature recovery ability of rock formation, it is not conducive to improving the system heat production efficiency.

10.11885/j.issn.1674-5086.2022.06.17.01