Adjustable Bent Drilling Tool Having in situ Drilling Direction Change Capability

Abstract

An adjustable bent drilling tool capable of changing in situ drilling direction to facilitate horizontal drilling. The drilling tool may be controlled from the surface and eliminates the need to bring the tool to the surface for reconfiguration. In one embodiment, the drilling tool utilizes a communications module to communicate with upstream sections of the tool. The communications module is connected to a programmable electronic control module which controls an electric motor. A hydraulic valve assembly follows the control module, which receives input signals and controls a pilot piston between two fixed points of a mid-assembly typically located adjacent to and downstream of the hydraulic valve assembly on the drill tool. A lower assembly is attached to the drill tool immediately following the mid-assembly, and provides both a safety release sub-assembly as well as a bendable sub-assembly which directs the adjustable drill tool to change drilling angle and direction.

What is claimed is: 
     
         1 . A coupling assembly for non-rotatably coupling two sections of a drill tool, comprising:
 a first cylindrical section having an annular cavity located concentrically within the first section, and a slot adjacent a first end of the first section;   a second cylindrical section having a circumferential groove disposed coaxially on the outer surface of the second section and adjacent a first annular end of the second section, the first end of the second section having a diameter smaller than the diameter of the cavity;   a pin hole located in the circumferential groove; and,   a semi-circular key, the key having a pin located at an end thereto;   wherein the first end of the second section is inserted into the annular cavity of the first section such that the pin hole is aligned with the slot, the semi-circular key used to operatively couple the first and second cylindrical sections together.   
     
     
         2 . The coupling assembly of  claim 1  wherein the pin of the key is inserted into the pin hole and the second section is rotated relative to the first section such that the key is secured into an annular space formed between the first and second sections.