雄安牛驼镇地热田岩溶热储层地热深井井身结构优化设计

雄安新区牛驼镇地热田主要储层为岩溶热储型,地层破碎、裂隙发育,钻进时多失返性漏失。以往的开发主要集中于1800 m以浅,岩溶热储段长为300~500 m,裸眼段较短,钻进施工较简单。为了加强对深部地热资源的探测,满足雄安新区规划建设的需求,开展了深部地热资源调查工作,主要目的层为雾迷山组和高于庄组,其存在的难点主要有岩溶热储层裸眼段长、地层破碎、长段漏失、上部地层稳定性差等。本文对地热深井施工过程中钻遇的问题及难点进行了深入的分析,从一开下深、井径级配等方面提出了优化建议,并总结了施工关键技术,以提高地热深井的安全稳定性。

Optimization design of the geothermal wellbore structure in karst reservoir

The main geothermal reservoir is of a thermal karst type in the Niutuo geothermal field in Xiongan New District.In the past,the development was concentrated mainly at the depth less than 1800m,where the length of karst reservoir is 300 to 500m with short open hole section,hence simple drilling.In order to strengthen the exploration of deep geothermal resources and satisfy the needs of the planning and construction of Xiongan New District,investigation of deep geothermal resources was carried out with Wumishan Formation and Gaoyuzhuang Formation as the main targets.The main difficulties included the long open?hole section in the Karst Reservoir,broken formation,circulation loss over long well sections,poor stability of the upper strata.With analysis of drilling problems and difficulties encountered in drilling of the deep thermal exploration wells,the optimization suggestions are put forward for design of the well structure,and the key techniques for drilling in the karst thermal reservoir are summarized so as to effectively improve the safety and stability.