新型同径分层止水工艺在地热探采深井的应用

Application of new single diameter multi-level water sealing technology in geothermal exploration and production wells

摘要:

原平大营地热探采结合深井完钻井深3088 m，为探明494~3088 m变质岩地层的水文地质参数和水源补给情况，基于岩心和测井资料划分4个抽水试验段，且试验后需要恢复目的含水层。根据“一孔同径分层止水”原则，设计了管内止水托盘止水、管外止水伞止水的新型同径分层止水工艺。该工艺简化了井身结构，避免了管外投粘土球、注水泥等堵塞含水层的情况。现场实施表明，该工艺止水效果完全满足水文地质抽水试验要求，可为同类工程提供经验和借鉴。

Abstract:

The well designed for geothermal exploration and production in Daying， Yuanping was completed at depth of 3088m. To find out hydrogeological parameters and water recharge of 494~3088m formation， it was divided with four pumping test sections based on core and logging data； meanwhile， the target aquifer needed to be restored as much as possible after tests. According to the principle of “multi-level sealing in a single diameter hole”， a new water sealing process was designed with the water-stop tray for inside-pipe sealing and the canvas umbrella for outside-pipe sealing. This process simplifies the well structure and avoids clogging caused by dropping clay balls， injecting cement， etc. from outside the pipe. Field use shows that this process meets the water-sealing requirements of hydrogeological pumping tests， and can provide reference for similar projects.