STUDY AND APPLICATION OF NEW HINGE TYPE BOTTOM HOLE ASSEMBLY

A new hinge type bottom hole assembly used in straight well for well inclining prevention and hole straightening was put forward account to the fact that the actual pendulum and packed drill assemblies were not satisfactory for inclining prevention and hole straightening in formations with strong natural deflecting build up capacity. Meanwhile a mechanical model of this kind of bottom hole assembly was set up and its mechanism of inclining prevention and hole straightening was described. The influences of structural parameters of the bottom hole assembly and drilling technological indices on bit lateral force were also analyzed in detail and a comparison of bit lateral deflecting decreasing fOrce of this drill assembly with pendulum assembly was done. The rig-site applications revealed that the deflecting decreasing effect of this assembly was evident when it was used fast deflecting rectifying with normal drilling weight and the penetration rate approached to the normal case.