Wellbore cleaning device

Claim 3

Apparatus for cleaning out a portion of an internal surface of a highly-angulated wellbore prior to running a string of casing in order to dislodge cuttings which have gravitationally settled out of a mud stream and become caked on a lower portion of said wellbore, said apparatus comprising: a scouring brush means affixed to a leading end of a drill string, said drill string having substantial weight per unit length; means for advancing said scouring brush means through a portion of the highly-angulated wellbore to be cleaned; a helical driving surface affixed to said scouring brush means for rotating said scouring brush means during advancement to enhance dislodgement of said caked cuttings, and the like, from said lower portion of said wellbore; means for supporting said brush means in a position that is generally centered within the wellbore so as not to permit the weight of said drill string to ride on said brush; means to reverse circulate drilling fluid in said highly-angulated wellbore to entrain said recently dislodged cuttings and carry them upwardly out of said wellbore through said drill string.

Claim 4

Apparatus for cleaning out a portion of an internal surface of a highly-angulated wellbore prior to running a string of casing in order to dislodge cuttings which have gravitationally settled out of a mud stream and become caked on a lower portion of said wellbore, said apparatus comprising: a scouring brush means affixed to a leading end of a drill string, said drill string having substantial weight per unit length; means for advancing said scouring brush means through a portion of the highly-angulated wellbore to be cleaned; a helical driving surface affixed to said scouring brush means for rotating said scouring brush means during advancement to enhance dislodgement of said caked cuttings, and the like, from said lower portion of said wellbore; means for supporting said brush means in a position that is generally centered within the wellbore so as not to permit the weight of said drill string to ride on said brush; means to reverse circulate drilling fluid in said highly-angulated wellbore to entrain said recently dislodged cuttings and carry them upwardly out of said wellbore through said drill string.

Claim 5

The apparatus of claim 2 wherein said means for supporting said brush means comprises dolly means mounted about the drill string periphery.

Claim 6

The apparatus of claim 3 wherein said dolly means comprises a plurality of sets of caster members.

Claim 7

The apparatus of claim 4 wherein each set of caster members comprise three casters equally spaced about said drill string periphery.

Claim 8

The apparatus of claim 5 wherein the casters of a second set of said plurality of sets of caster members are laterally offset with respect to the casters of a first set of caster members.

Claim 9

The apparatus of claim 5 wherein each of such casters is resiliently mounted to permit accomodation for dimensional variations in said wellbore.

Claim 10

The apparatus of claim 5 wherein each of said casters comprises a wheel with a rotational axis that extends generally orthogonally to the longitudinal axis of said drill string.

Claim 11

The apparatus of claim 5 wherein each of said casters comprises a free-floating sphere mounted in and partially extending from a housing permitting said sphere at least two degrees of rotational freedom in order to facilitate the translational and rotational movement of said scouring brush means.

Claim 12

The apparatus of claim 2 wherein said helical driving surface is affixed to an external surface of said scouring brush means.

Claim 13

The apparatus of claim 2 wherein said helical driving surface is affixed to an internal surface of said scouring brush means.

Claim 14

The apparatus of claim 2 wherein said means for rotating said scouring brush means further comprises said drilling fluid which has sufficient hydraulic pressure when directed into contact with said helical driving surface as to rotate said scouring brush means.

Claim 15

The apparatus of claim 2 comprising an end section with a first portion which fixedly mounts said brush means at least said first portion of said end section being rotatable with respect to a second non-rotatable portion of said drill string.

Claim 16

The apparatus of claim 13 further comprising bearing means between said rotatable and non-rotatable portions to facilitate rotation of said brush means.

Claim 17

The apparatus of claim 14 further comprising seal means for inhibiting flow of said drilling fluid between said rotatable and said non-rotatable portions.

Claim 18

The apparatus of claim 15 wherein said seal means comprises at least one low-pressure, low-friction seal member.

Claim 19

Apparatus for cleaning out a portion of an internal surface of a highly-angulated wellbore prior to running a string of casing in order to dislodge cuttings which have gravitationally settled out of a mud stream and become caked on a lower portion of said wellbore, said apparatus comprising: a scouring brush means affixed to a first leading end portion of a drill string, said drill string having substantial weight per unit length and said first leading end portion being rotatable with respect to a second non-rotatable portion of said drill string; means for advancing said scouring brush means through a portion of the highly-angulated wellbore to be cleaned; means for rotating said scouring brush means during advancement to enhance dislodgement of said caked cuttings, and the like, from said lower portion of said wellbore; means for supporting said brush means in a position that is generally centered within the wellbore so as not to permit the weight of said drill string to ride on said brush; means to reverse circulate drilling fluid in said highly-angulated wellbore to entrain said recently dislodged cuttings and carry them upwardly out of said wellbore through said drill string.

Claim 20

Apparatus for cleaning out a portion of an internal surface of a highly-angulated wellbore prior to running a string of casing in order to dislodge cuttings which have gravitationally settled out of a mud stream and become caked on a lower portion of said wellbore, said apparatus comprising: a scouring brush means affixed to a first leading end portion of a drill string, said drill string having substantial weight per unit length and said first leading end portion being rotatable with respect to a second non-rotatable portion of said drill string; means for advancing said scouring brush means through a portion of the highly-angulated wellbore to be cleaned; means for rotating said scouring brush means during advancement to enhance dislodgement of said caked cuttings, and the like, from said lower portion of said wellbore; means for supporting said brush means in a position that is generally centered within the wellbore so as not to permit the weight of said drill string to ride on said brush; means to reverse circulate drilling fluid in said highly-angulated wellbore to entrain said recently dislodged cuttings and carry them upwardly out of said wellbore through said drill string.

Claim 21

The apparatus of claim 17 wherein said means for rotating said scouring brush means comprises a helical driving surface affixed to said first leading end portion.

Claim 22

The apparatus of claim 18 wherein said means for rotating said scouring brush means comprises, at least in part, said reverse-circulated drilling fluid which, when directed against said helical driving surface, has sufficient hydraulic pressure to rotate said scouring brush means.

Claim 23

The apparatus of claim 17 wherein said helical surface is affixed to an external surface of said first leading end portion.