Methods and apparatus for controlled directional drilling of boreholes

Directional drilling apparatus adapted for drilling a borehole along one or more selected axes and comprising:

• a body having a longitudinal passage and adapted to be dependently supported in a borehole and rotated by a tubular drill string in which a drilling fluid is circulating;
• earth-boring means coupled to said body for rotation thereby and including two or more fluid outlets in communication with said longitudinal passage and respectively adapted for discharging separate streams of drilling fluid into adjacent borehole sectors upon rotation of said earth-boring means to clear away formation materials from said earth-boring means and adjacent borehole surfaces;
• and
• direction controlling means including fluid-directing means selectively operable upon rotation of said earth-boring means for either discharging streams of drilling fluid from each of said fluid outlets into all adjacent angularly-spaced borehole sectors to direct said earth-boring means along a first course or discharging streams of drilling fluid from each of said fluid outlets into only a single adjacent borehole sector to redirect said earth-boring means along a second course.

Directional drilling apparatus adapted for drilling a borehole along one or more selected axes and comprising:

• a first body having a fluid passage therein and adapted to be dependently suspended in a borehole and rotated by a tubular drill string in which a drilling fluid is circulating;
• a rotary drill bit including a second body coupled to said first body for rotation thereby, means on said second body defining at least three separate fluid passages operatively arranged and adapted upon rotation of said drill bit for respectively discharging separate angularly-displaced streams of a drilling fluid into adjacent borehole sectors to clear away formation materials from ahead of said drill bit and on adjacent borehole surfaces;
• direction-controlling means including fluid-directing means operatively arranged in one of said bodies for selectively communicating said fluid passages upon rotation of said drill bit and including a flow obstructing member, means rotatably journaling said flow obstructing member in one of said bodies for rotation between successive operating positions respectively obstructing fluid communication through at least one of said three separate passages and establishing fluid communication in the remaining separate passages, driving means selectively operable for rotating said flow-obstructing member between its said successive operating positions in a first mode of operation selected to sequentially discharge drilling fluid from each of said three separate passages into adjacent angularly-displaced borehole sectors to uniformly clear away formation materials ahead of said drill bit and for rotating said flow-obstructing member between its said successive operating positions in a second mode of operation to sequentially discharge drilling fluid from each of said separate fluid passages into only into a single borehole sector to preferentially clear away formation materials in said single borehole sector ahead of said drill bit.

A method for selectively excavating an inclined borehole with rotatable earth-boring apparatus suspended from a tubular drill string having a drilling fluid circulating therethrough, said earth-boring apparatus having a plurality of fluid passages respectively arranged therein for discharging a stream of said drilling fluid into an adjacent sector of said inclined borehole as said earth-boring apparatus is being advanced, and comprising the steps of:

• determining the azimuthal direction and angular inclination in which said earth-boring apparatus is advancing in said inclined borehole;
• whenever said earth-boring apparatus is advancing in a selected azimuthal direction, discharging said drilling fluid in a controlled sequence from each of said fluid passages as said earth-boring apparatus is rotating for selectively directing said streams of drilling fluid into angularly-separated sectors of said inclined borehole to advance said earth-boring apparatus further in said selected azimuthal direction as it continues to excavate said inclined borehole;
• whenever said earth-boring apparatus is advancing at a selected angular inclination, discharging said drilling fluid in a controlled sequence from each of said fluid passage as said earth-boring apparatus is rotating for selectively directing said streams of drilling fluid into angularly-separated sectors of said inclined borehole to advance said earth-boring apparatus further at said selected angular inclination as it continues to excavate said inclined borehole;
• whenever said earth-boring apparatus is not advancing in said selected azimuthal direction, discharging said drilling fluid in a controlled sequence from each of said fluid passages as said earth-boring apparatus is rotating for selectively directing said streams of drilling fluid into only a single selected sector of said inclined borehole to divert said earth-boring apparatus toward said selected azimuthal direction as it continues to excavate said inclined borehole;
• and
• whenever said earth-boring apparatus is not advancing at said selected angular inclination, discharging said drilling fluid in a controlled sequence from each of said fluid passages as said earth-boring apparatus is rotating for selectively directing said streams of drilling fluid into only a single selected sector of said inclined borehole to divert said earth-boring apparatus toward said selected angular inclination as it continues to excavate said inclined borehole.

A method for excavating an inclined borehole along selected courses of excavation with rotatable earth-boring apparatus suspended from a tubular drill string having a drilling fluid circulating therethrough, said earth-boring apparatus having a plurality of fluid passages respectively arranged therein for discharging a stream of said drilling fluid into an adjacent sector of said borehole, and comprising the steps of:

• while said earth-boring apparatus is advancing along a first course of excavation, obtaining measurements representative of the azimuthal direction of said first course of excavation in relation to a selected first azimuthal direction;
• so long as said measurements indicate that said earth-boring apparatus is advancing in said first azimuthal direction, sequentially discharging said streams of drilling fluid from each of said fluid passages into angularly-separated sectors of said borehole while rotating said earth-boring apparatus for progressively excavating a first inclined interval of said borehole in said first azimuthal direction;
• whenever said first inclined interval is to be terminated, sequentially discharging said drilling fluid from each of said fluid passages into only a selected sector of said borehole lying in a selected second azimuthal direction while rotating said earth-boring apparatus for diverting said earth-boring apparatus to a second course of excavation;
• while said earth-boring apparatus is advancing along said second course of excavation, obtaining additional measurements representative of the azimuthal direction of said second course of excavation in relation to said second azimuthal direction;
• and
• once said additional measurements indicate that said earth-boring apparatus is advancing in said second azimuthal direction, sequentially discharging said streams of drilling fluid from each of said fluid passages into angularly-separated sectors of said borehole while rotating aid earth-boring apparatus for progressively excavating a second inclined interval of said borehole in said second azimuthal direction.

A method for drilling a borehole with a rotary drill bit suspended from a rotatable tubular drill string having a drilling fluid circulating therethrough, said drill bit having a plurality of fluid passages arranged therein for respectively discharging a stream of drilling fluid into an adjacent peripheral sector of said borehole, and comprising the steps of:

• rotating said drill string for operatively rotating said drill bit to drill a borehole into the earth;
• sequentially discharging said drilling fluid from each of said fluid passages into multiple peripheral sectors of said borehole as said drill bit rotates for progressively drilling a first interval of said borehole along a generally-linear course of excavation;
• whenever an inclined interval of said borehole is to be drilled in a selected azimuthal direction, sequentially discharging said drilling fluid from each of said fluid passages into only a single peripheral sector of said borehole facing in said selected azimuthal direction as said drill bit rotates for progressively drilling a second interval of said borehole along a generally-arcuate course of excavation toward said selected azimuthal direction;
• obtaining measurements indicative of the direction of advancement of said drill bit in said second borehole interval in relation to said selected azimuthal direction;
• and
• whenever said directional measurements indicate that said drill bit is then advancing in said selected azimuthal direction, sequentially discharging said drilling fluid from each of said fluid passages into multiple peripheral sectors of said borehole as said drill bit rotates for progressively drilling an inclined third interval of said borehole along a generally-linear course of excavation in said selected azimuthal direction.