摘要
地热井开发过程中的碳酸钙结垢严重制约了地热能的可持续开发利用,为了给地热井阻垢技术的应用提供理论依据,对河北博野地热井X井结垢位置进行了数值模拟研究。基于地热井井身结构,利用WELLSIM软件,进行了结垢位置预测和结垢影响因素分析研究。研究结果表明:根据出口流体成分反推得到的井底流体温度为128.0℃;地热流体沿井筒上升过程中压力迅速降低,在井下56.10 m处发生闪蒸,其干度、CO2分压随之发生突变;地热井内流体闪蒸位置随CO2质量分数、NaCl质量分数和地热流体流量增大而下移,其中CO2质量分数对地热水闪蒸位置的影响最大。现场防垢时,潜水泵的下入深度或阻垢剂的加注深度均应在闪蒸点56.10 m以下。研究表明,控制井口压力和流量可以调节闪蒸位置,实现地热开采与防垢技术的协同优化。
Calcium carbonate scaling in geothermal wells seriously hinders the sustainable development and utilization of geothermal energy.In order to provide a theoretical basis for the implementation of scale inhibition technology in geothermal wells,the scaling spots of a geothermal well in Boye County of Hebei Province were numerically simulated.Based on the casing program of geothermal wells,the influencing factors and scaling spot depth prediction were studied by using WELLSIM.The results showed that fluid temperature at the bottomhole calculated from the composition of outlet fluids was 128.0℃.The geothermal fluid pressure drops rapidly as it rose along the wellbore.A flash occurred at the depth of 56.10 m,the dryness and CO2 partial pressure sharply changed accordingly.The flash depth of geothermal fluids migrated downwards with the increase of CO2 mass fraction,NaCl mass fraction and geothermal fluid flow rate,in which CO2 mass fraction played the decisive role.In field scale prevention practice,the setting depth of the submersible pump and the injection depth of the scale inhibitor should be below the flash depth of 56.1 m.The research shows that the flash depth can be adjusted by controlling the wellhead pressure and flow rate to accomplish the collaborative optimization of geothermal exploitation and scale prevention.
作者
梁海军
郭啸峰
高涛
卜宪标
李华山
王令宝
LIANG Haijun;GUO Xiaofeng;GAO Tao;BU Xianbiao;LI Huashan;WANG Lingbao(New Energy Research Institute,Sinopec Star Petroleum Co.,Ltd.,Beijing,100083,China;China National Research and Technology Center of Geothermal Energy,Beijing,100083,China;Guangzhou Institute of Energy Conversion,Chinese Academy of Sciences,Guangzhou,Guangdong,510640,China;Key Laboratory of Renewable Energy,Chinese Academy of Sciences,Guangzhou,Guangdong,510640,China;Guangdong Key Laboratory of New and Renewable Energy Research and Development,Guangzhou,Guangdong,510640,China)
出处
《石油钻探技术》
CAS
CSCD
北大核心
2020年第5期105-110,共6页
Petroleum Drilling Techniques
基金
国家重点研发计划项目“井储防垢除垢关键技术及工艺”(编号:2019YFB1504104)
中国石化集团科技攻关项目“中高温地热水防垢除垢技术研究”(编号:JP18063-2)部分研究内容。
关键词
地热井
碳酸钙
结垢
闪蒸位置
防垢
二氧化碳
geothermal well
calcium carbonate
scaling
flashing depth
antiscale
carbon dioxide
