Apparatus for optional straight or directional drilling underground formations

Claim 1

A device for use in underground directional drilling of boreholes in which either a straight borehole may be drilled or wherein a borehole having a predetermined radius of curvature may be drilled while said device is positioned in a borehole comprising: a tubular housing comprising upper, intermediate and lower sections connected to one another; a down-hole motor mounted in the upper section of said housing and having an output shaft; means for connecting said output shaft to a drill bit located below the lower section of said housing; means for connecting said housing to a drill string such that the axis of said upper section is initially essentially in alignment with the axis of said drill string; first and second stabilizers mounted on said housing; said first stabilizer being associated with said lower section of said housing and said second stabilizer being associated with said upper section of said housing; said upper section having a longitudinal axis and said lower section having a longitudinal axis which is arranged at an angle relative to the axis of said upper section; and said intermediate section having a longitudinal axis which intersects said upper and lower axes whereby upon rotation of said drill bit by rotating said said drill string and simultaneously rotating said motor an essentially straight borehole is drilled and whereby rotating said drill bit by rotation of said motor while said drill string is not rotated a curved borehole having a predetermined radius of curvature is drilled.

Claim 2

A device for use in underground directional drilling of boreholes in which either a straight borehole may be drilled or wherein a borehole having a predetermined radius of curvature may be drilled while said device is positioned in a borehole comprising: a tubular housing comprising upper, intermediate and lower sections connected to one another; a down-hole motor mounted in the upper section of said housing and having an output shaft; means for connecting said output shaft to a drill bit located below the lower section of said housing; means for connecting said housing to a drill string such that the axis of said upper section is initially essentially in alignment with the axis of said drill string; first and second stabilizers mounted on said housing; said first stabilizer being associated with said lower section of said housing and said second stabilizer being associated with said upper section of said housing; said upper section having a longitudinal axis and said lower section having a longitudinal axis which is arranged at an angle relative to the axis of said upper section; and said intermediate section having a longitudinal axis which intersects said upper and lower axes whereby upon rotation of said drill bit by rotating said said drill string and simultaneously rotating said motor an essentially straight borehole is drilled and whereby rotating said drill bit by rotation of said motor while said drill string is not rotated a curved borehole having a predetermined radius of curvature is drilled.

Claim 25

The method of directional drilling along a known predetermined radius of curvature wherein a drill string includes a bottom hole drilling assembly comprised of at least an upper section and a lower section and a downhole motor and wherein said upper section includes at least an upper component at least a portion of which contacts the bore wall and said lower section having an axis which is tilted with respect to said upper section and said lower section including a lower component at least a portion of which contacts the bore wall and said lower component being spaced from a drill bit connected to said lower section and wherein said downhole motor is connected to rotate said drill bit, the method comprising: assembling said drilling assembly to the drill string such that when said drill bit is rotated only by said motor, said drilling assembly drills a hole having a radius of curvature corresponding essentially to said predetermined radius of curvature, said step of assembling including the steps of: (a) mounting said respective components such that there is a predetermined known distance therebetween, (b) mounting said drill bit a predetermined known distance below said lower component such that the drill bit is on an axis which is tilted a known amount with respect to the axis of said drill string, (c) said radius of curvature being determined by the distance from a defined reference point to said upper component and which distance forms a radius for the radius of curvature, said defined point being defined by the intersection of one line perpendicular to the midpoint between the bit and the lower component and a second line perpendicular to the midpoint between the upper and lower components, lowering said drill string and said assembled bottom hole drilling assembly into a borehole, drilling a straight hole by simultaneously rotating both said drill string and said drill bit, the rotation of said drill bit being carried out by rotation of said downhole motor, and while said drill string and bottom hole drilling assembly are still positioned in said bore hole, rotating only said drill bit by operation of said downhole motor to drill a hole having a known radius of curvature which essentially corresponds to said predetermined radius of curvature.

Claim 26

The method of directional drilling along a known predetermined radius of curvature wherein a drill string includes a bottom hole drilling assembly comprised of at least an upper section and a lower section and a downhole motor and wherein said upper section includes at least an upper component at least a portion of which contacts the bore wall and said lower section having an axis which is tilted with respect to said upper section and said lower section including a lower component at least a portion of which contacts the bore wall and said lower component being spaced from a drill bit connected to said lower section and wherein said downhole motor is connected to rotate said drill bit, the method comprising: assembling said drilling assembly to the drill string such that when said drill bit is rotated only by said motor, said drilling assembly drills a hole having a radius of curvature corresponding essentially to said predetermined radius of curvature, said step of assembling including the steps of: (a) mounting said respective components such that there is a predetermined known distance therebetween, (b) mounting said drill bit a predetermined known distance below said lower component such that the drill bit is on an axis which is tilted a known amount with respect to the axis of said drill string, (c) said radius of curvature being determined by the distance from a defined reference point to said upper component and which distance forms a radius for the radius of curvature, said defined point being defined by the intersection of one line perpendicular to the midpoint between the bit and the lower component and a second line perpendicular to the midpoint between the upper and lower components, lowering said drill string and said assembled bottom hole drilling assembly into a borehole, drilling a straight hole by simultaneously rotating both said drill string and said drill bit, the rotation of said drill bit being carried out by rotation of said downhole motor, and while said drill string and bottom hole drilling assembly are still positioned in said bore hole, rotating only said drill bit by operation of said downhole motor to drill a hole having a known radius of curvature which essentially corresponds to said predetermined radius of curvature.