ROTARY STEERABLE DRILLING TOOL AND METHOD FOR DIRECTIONAL DRILLING

摘要

The device contemplated provides a method for positioning the drill bit (16) in a drilling operation to achieve small changes in hole angle or azimuth as drilling proceeds. Two different positions are available to the operator. The first is a straight ahead position where the tool essentially becomes a packed hole stabilizer assembly. The second position tilts the bit across a rotating fulcrum to give a calculated offset at the bit-formation interface. The direction that the bit offset is applied in relation to current hole direction is controlled by positioning the orienting pistons prior to each drilling cycle, through the use of current measurement-while-drilling (MWD) technology. Components of the tool comprise a MWD housing (14), upper steering and drive mandrel (50) , non-rotating position housing (32), lower drive mandrel (52) splined with the upper mandrel, rotating fulcrum stabilizer and drill bit.