Patent ID: 6810972
Filing Date: 2004-11-02
Classification: E21B

Abstract:
A steerable horizontal subterranean drill bit apparatus having a one bolt attachment system, the apparatus comprising:a steerable horizontal subterranean drill bit, a drill bit proximal end which is attachable to a housing, a drill bit distal end suitable for use in subterranean drilling, a longitudinal axis between said proximal and distal ends, a drill bit mounting face located at said drill bit proximal end, said mounting face being generally planar, said drill bit mounting face serving to abut against a housing to which said drill bit may be mounted, said drill bit mounting face including a plurality of stud receptacles therein, a plurality of locating studs mounted in said receptacles, said locating studs serving to project into holes on a housing and to bear against such holes in order to positively engage with a housing and fix the angular position of the drill bit with respect to the housing, a drill bit shank adjacent said mounting face, said shank being at least partially cylindrical in shape, said shank cylindrical portion having a longitudinal axis coincident with said drill bit longitudinal axis, said shank cylindrical portion having a radius Rshank said shank having a plurality of receptacles for receiving elevated wear protectors, a drill bit steering face, said steering face being generally planar in presentation, said steering face being situated along said drill bit shank in an angular orientation with respect to said drill bit longitudinal axis such that said steering face is neither parallel nor perpendicular to said drill bit longitudinal axis, said steering face intersecting said shank along an edge that is at least partially parabolic in shape, said steering face having at least one drilling fluid flow channel on its exterior to permit the drilling fluid to pass by said steering face during use of the drill bit; said steering face having a leading edge, said steering face having at least one receptacle for receiving at least one elevated wear protector therein, said steering face elevated wear protector receptacle being located in the vicinity of said leading edge, an elevated wear protector located in said steering face leading edge receptacle, said steering face leading edge elevated wear protector serving to protect said steering face leading edge from abrasive wear, at least some of said shank elevated wear protector receptacles being located along said steering face to shank parabolic intersection, said shank elevated wear protector receptacles having elevated wear protectors installed therein, said elevated wear protector receptacles serving to protect against abrasive wear, a crown located adjacent said shank and adjacent said steering face, said crown being located closer to said drill bit distal end than said shank, said crown having a plurality of receptacles thereon for placement of elevated wear protectors therein, said crown having an exterior surface that is at least partially cylindrical in shape, said crown cylindrical portion with radius Rcrown, said radius Rcrown being greater than said radius Rshank, a cutting face located at said drill bit distal end, said cutting face having a plurality of receptacles for receiving cutting teeth therein, each of said cutting face receptacles being situated at an angular orientation with respect to said drill bit longitudinal axis that is neither parallel nor perpendicular to said drill bit longitudinal axis, each of said cutting face receptacles being situated at an angular orientation with respect to each of said other cutting face receptacles so that no cutting face receptacle longitudinal axis is parallel to any other cutting face receptacle longitudinal axis, a plurality of cutting teeth located in said cutting face receptacles, the number of said cutting teeth being represented by the letter â€œiâ€  where â€œiâ€  is an integer, said cutting teeth being situated so that when the drill bit is rotated about its longitudinal axis, each cutting tooth â€œiâ€  circumscribes a circle Ci, where each such circle Ci is defined by a radius Ri, such that each Ri is not equal to Ri+1, so that when the drill bit is rotated about its longitudinal axis, the cutting teeth define a cutting path that includes offset overlapping cutting tooth patterns, said drill bit mounting face being situated at an angular orientation with respect to said drill bit longitudinal axis that is selected to be an angular orientation other than perpendicular and parallel, so that when a housing to which the drill bit is affixed is rotated, each cutting tooth â€œiâ€  moves in a manner that circumscribes a circle Câ€²i where each such circle Câ€²i is defined by a radius Râ€²i, such that for any cutting tooth â€œiâ€ , Râ€²i is greater than Ri, a bore through said drill bit, said drill bit bore being located generally parallel with said drill bit longitudinal axis, said drill bit bore having a first orifice in the vicinity of said drill bit mounting face, said drill bit bore having a second orifice which may be accessed from at least one of said steering face and said cutting face, said drill bit bore being configured to accommodate a one bolt attachment therethrough in order to secure the drill bit to a housing, said one bolt attachment serving to fix the longitudinal position of the drill bit with respect to a housing, and in combination with said locating studs, to positively engage a housing so that the drill bit may be used for drilling.