Bit feed principles and operations of slide drilling

Slide bit feed is often used in the drilling of directional and horizontal wells. How the surface intermittently feeding of drill pipe into the well transfers to down hole drill bit pushing? How to reduce the WOB error due to slide friction between the drill string and the borehole wall? What are the advantages and disadvantages of the existing sliding drilling bit feed technologies? In order to answer these questions, this paper first introduces bit feed principles of the down hole drill string elasticity, the hydraulic oscillator and the hydraulic thruster. Then, introduces the relationships between surface drilling parameters and bottom hole drilling parameters for slide feeding technology of the BHA only with motor, and it also with hydraulic oscillator or it also with hydraulic thruster. Finally, these three technologies are compared. The best is the slide feeding technology of BHA with the hydraulic thruster, WOB is smooth and adjustable, the hydraulic thrusters can be used in tandem and the upper part of the drill string can make short trip while the bit is drilling. Two potential devices facilitating slide feeding are introduced.