LONG REACH ROTARY DRILLING ASSEMBLY

摘要

A long reach rotary drilling assembly comprises an elongated conduit, a dril l bit (122), a 3-D steering tool (118) on the conduit, and a tractor (110) on the conduit for applying force to the drill bit. The steering tool includes a telemetry section (100), a rotary section (224), and a flex section (272) assembled as an integrated system in series along the length of the tool. Th e flex section (226) comprises a flexible drive shaft (244) to which a bending force is applied when making inclination angle adjustments. The rotary secti on (224) includes a deflection housing which rotates for making a azimuth angle adjustments. The telemetry section (100) receives inclination and azimuth angle steering commands together with actual inclination and azimuth angle feedback signals for controlling course. A propulsion assembly moves the tractor with respect to the gripper (1104) while the gripper portion is in t he first position. The tractor (110) applies force to the drill bit for drillin g the bore along a desired course the direction of which is controlled by the 3- D steering tool (118).