VTK垂直钻井系统在龙深1井钻井中的应用

龙深1在钻遇推覆体地层时，地层倾角变化大，自然造斜能力强，采用塔式钻具、钟摆钻具、大尺寸PDC钻头等多种防斜技术，其结果是井斜控制十分困难、钻井速度极慢；利用弯螺杆＋转盘钻井复合技术，虽然钻井速度有一定的提高，但仍不能达到提速的目的。为提高机械钻速，引进贝克休斯的VTK垂直钻井技术，它是由AUTOTRAK（闭环旋转导向系统）、高性能X-TREME马达、可靠的MWD三种技术开发出来的一种闭环自动垂直钻井技术，能够根据井眼的偏斜，经井下微处理器分析判断，使导向稳定地靠近井眼高边方向导向肋板伸出顶向上井壁，这样使钻头产生合理的降斜力，从而使井眼回到垂直轨道上来。现场应用表明：该技术较好地解决了钻井提速工作中井斜与钻压之间的矛盾，使钻井效率明显提高；为充分发挥该技术的作用，需要选择合适的钻头类型和合理的钻井液性能

Application of VTK Vertical Drilling System in the Well Longshen-1

Drilling through the thrust block in the well Longshen 1 had encountered the problem of strong natural formation deflection tendency due to high formation dip variation. The combination of tapered assembly, pendulum assembly and large diameter PDC bit had resulted in difficult deviation control and low ROP. The composite drilling using bent sub PDM and rotary drilling had improved the ROP to some extent, but still far from the desired ROP improvement goal. So in order to improve ROP, the VTK vertical drilling technology of Baker Hughes was introduced. VTK is a kind of closed loop, automatic, and vertical drilling technology, made up of closed loop rotary steering drilling system AUTOTRAK, high performance X-TREME motor and reliable MWD. It is able to return the well path back to vertical by adopting downhole microprocessors to analyze the measured deviation data and determine the proper force necessary for decreasing the deviation angle to guide the steering rib at the high side to reliably stick out against the upper wellbore. The field application shows that this technology can solve the contradiction between hole deviation and WOB during fast drilling, the drilling efficiency can be increased very obviously.However, it is to be noted that proper selection of bit type and drilling fluid properties are required for taking full advantages of this technology.