旋冲螺杆钻具在硬岩地热钻探中的应用研究

Application study of rotary⁃percussive screw drilling toolin hard⁃rock geothermal drilling

针对目前地热钻探中,在花岗岩、片麻岩等硬岩地层中机械钻速低的问题,引入一种机械式旋冲螺杆钻具,先后在JHR-1井花岗岩地层及HG-1井片麻岩地层中进行了试验应用。与普通螺杆钻具相比,旋冲螺杆钻具在JHR-1井Ø215.9 mm井段、HG-1井Ø215.9 mm井段和Ø311.2 mm井段机械钻速分别提高了10%、8.4%和7.6%,同时,旋冲螺杆钻具使用过程中未产生其他副作用。试验证明使用旋冲螺杆钻具可以有效地提高花岗岩、片麻岩等硬岩地层的机械钻速,为旋冲螺杆钻具在硬岩地层地热钻探中的应用推广打下了基础。

In view of the problem of low mechanical drilling speed in the hard rock such as granite and gneiss in the geothermal drilling at present,a mechanical rotary‑percussive screw drilling tool is introduced and tested in granite formation of JHR-1 well and gneiss formation of HG-1 well.Compared with the ordinary screw drilling tool,the mechanical drilling speed of the rotary‑percussive screw drilling tool increases respectively by 10%,8.4%and 7.6%inØ215.9 mm well section of JHR-1,Ø215.9 mm andØ311.2mm well section of HG-1,and no other side effects exist during the drilling process.The test proves that the mechanical drilling speed can be effectively improved by the use of rotary‑percussive screw drilling tool,which provides a foundation for the application and popularization of the rotary‑percussive screw drilling tool in the drilling of hard rock such as granite and gneiss.