川渝页岩气水平井水平段“一趟钻”关键技术与进展

CRITICAL TECHNIQUES TO ENSURE ONLY ONE BIT RUN WHEN DRILLING HORIZONTAL INTERVAL DRILLING THROUGH SHALE AT SICHUAN AND CHONGQING AREA AND TECHNICAL ADVANCEMENTS

通过技术创新与集成应用,实现一只钻头、一套钻具组合、一次起下钻“一趟钻”钻完某个开次或某个井段的所有进尺,是缩短钻井周期、减少工程费用的有效途径。北美页岩气通过推广应用“一趟钻”,实现了“日进尺一英里”,提速提效效果明显。川渝页岩气岩石可钻性差,地质条件更加复杂,实现“一趟钻”面临着更大的挑战,由于机械钻速慢、部分工具寿命短、井下复杂多,川渝页岩气1500 m水平段通常需要3趟钻以上才能完成,亟待攻关解决。为此,分析了川渝页岩气水平井地质工程难点,探讨了“一趟钻”关键技术与工具,通过优化PDC钻头、旋转阀式MWD、钻柱扭摆系统,配套旋转导向、油基钻井液技术,建立了水平段“一趟钻”技术模板,评价了“一趟钻”实施效果与存在的问题,为提高“一趟钻”成功率,助推钻井提速提效提供了良好的基础参考。

Drilling of one spud or one complete interval with only one bit,one BHA in one trip is an effective way to shorten drilling cycle and reduce engineering costs.Through one bit run drilling in North America,a daily drilling footage of one mile per day has been realized,the ROP improvement results are very obvious.In Sichuan and Chongqing,the shale gas formation is featured with poor drillability and more complicated geologic conditions,posing greater challenges on one bit run drilling.Normally to complete 1500m long horizontal intervals in shale formations in Sichuan-Chongqing,not less than 3 bit runs are required due to the low ROP,short working life of some tools and complex problems dowhole.Study has been done on critical techniques and tools for one bit run drilling,a technical pattern is thus set up,the results and related problems evaluated,which will provide a basic reference for ROP improvement.