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.