摘要
在中深层地热资源的开发中,存在成本高、技术难、井筒易结垢和腐蚀等问题。单井井下换热器开采具有“取热不取水”的特点,能有效解决回灌中腐蚀结垢问题,是一种低成本、低环保风险的新兴技术,对中深层地热资源开发具有重要意义。基于国内外单井井下换热器的理论研究和现场应用状况,解释不同类型的单井井下换热器的工作原理,对比分析3种类型的单井井下换热器开采的优缺点,提出未来的发展方向。研究结果表明:①在中深层单井井下换热技术中,同轴套管井下换热器换热效率高,技术成熟,现场完井深度可达2300 m,出口水温超过40℃,热能产出可达220 MWh/a;②超长重力热管换热器具有避免工质损失、减少压裂等优点。虽然目前现场应用较少,但其产出温度超过100℃,具有巨大的发展潜力;③U型管换热器虽然换热量低,但具有安装简便,不易渗漏的优点,目前现场应用很少。基于U型管换热器在浅层地热资源开发中的重要性,它也将成为未来中深层单井换热的主攻方向之一。
For most mid-deep geothermal resources,their development is confronted with a series of problems,such as high cost,difficult to use techniques,and easy scaling and corrosion at wellbore.However,single-well heat exchanger,as an emerging cost-effective and environment-friendly technique to"extract heat without water"while effective avoiding the scaling and corrosion during recharge,is of great significance to the development.So,based on both theoretical research and field application of various single-well downhole heat exchangers around the world,their working principle was analyzed,both advantages and disadvantages of three heat exchangers were compared,and their future development direction was put forward.Results shows that:(1)as one mature technique,the downhole coaxial casing heat exchanger is featured by the highest efficiency,the on-site completion depth up to 2300 m,the outlet water temperature above 40℃,and the heat output reaching 220 MWh/a;(2)the gravity heat pipe heat exchanger with super long length can effectively avoid quality loss and reduce fracturing.Even though a little application,its output temperature can achieve higher than 100℃,indicating huge development potential;and(3)characterized by low capacity,but simple installation and leak resistance,the U-tube heat exchanger is seldom used on site.Since the U-tube one is critical in developing shallow geothermal resources,it is expected to be the major option for mid-deep geothermal resources.
作者
李海福
杨宇
宋荣彩
王玉婷
孙晗森
郑丽婧
Li Haifu;Yang Yu;Song Rongcai;Wang Yuting;Sun Hansen;Zheng Lijing(College of Energy,Chengdu University of Technology,Chengdu,Sichuan 610059,China;CNOOC Research Institute,Beijing 100027,China)
出处
《天然气勘探与开发》
2021年第3期118-126,共9页
Natural Gas Exploration and Development
基金
中海石油(中国)有限公司“地热资源利用可行性研究”(编号:ZYJSA2020-317)。
关键词
地热资源
井下换热器
单井换热
同轴套管
超长重力热管
U
型管
Geothermal resources
Downhole heat exchanger
Single-well heat exchange
Coaxial casing
Gravity heat pipe with super long length
U-tube
