Variable outside diameter tool for use in pikewells

A drill string stabiliser comprising a tubular member having a longitudinal axis, an external surface of said tubular member supporting a first circumferentially rotatable member and a second circumferentially rotatable member, the first and second circumferentially rotatable members being axially spaced from one another and resilient means being provided for producing a resilient force to urge said first and second circumferentially rotatable members toward one another, a radially movable member which is movable in a radial direction with respect to said longitudinal axis toward and away respectively from said external surface, said radially movable member being supported by the first and second circumferentially rotatable members, there being a taper on a radially outer side from said longitudinal axis on at least one of the first and second circumferentially rotatable members, a complementary taper with said taper on a radially inner side of the radially movable member for sliding abutment between said complementary taper and said taper, a radially outer surface of said radially movable member having a pair of oppositely angled tapers facing in opposing longitudinal axial directions, whereby said resilient means urges the first and second circumferentially rotatable members toward one another so as to urge the radially movable member along said sliding abutment radially outwardly from said longitudinal axis, and when said oppositely angled tapers meet an obstruction in a pipewell and the reactive force produced therebetween exceeds said resilient force then the radially movable member is urged inwardly along said sliding abutment to move the first and second circumferentially rotatable members axially apart against the force of said resilient means.

An underreamer for use downhole comprising a support tubular member having a longitudinal axis for connection to a drilling string, an external surface of said support tubular member supporting a movable member which is axially movable therealong and a further member axially spaced from said movable member, a radially movable member which is movable in a radial direction with respect to said longitudinal axis toward and away respectively from said external surface, said radially movable member being supported radially outwardly from said support tubular member by said axially movable member and said further member, a taper on a radially outer side from said longitudinal axis on at least one of said axially movable member and said further member, a complementary taper with said taper on a radially inner side of the radially movable member for sliding abutment between said complementary taper and said taper to permit expansion and contraction respectively of said radially movable member, a radially outer surface of said radially movable member having a pair of oppositely angled tapers facing in opposing longitudinal axial directions, resilient means for exerting a resilient force on said axially movable member in an axial direction toward said further member to urge said radially movable member along said sliding abutment in a radially outward direction from said longitudinal axis, and cutting means provided on a downhole facing one of said oppositely angled tapers and whereby when a leading one of said oppositely angled tapers meets an obstruction in a pipewell and the reactive force produced therebetween exceeds said resilient force then said radially movable member is thereby urged inwardly so that said sliding abutment moves the axially movable member away from said further member against the force of said resilient means.

A packer retriever comprising a support tubular member for connection to a drilling string, a longitudinal axis of said tubular member, an external surface of said support tubular member supporting a movable member which is axially movable therealong and a further member axially spaced from said movable member, a radially movable member defining a packer catching portion which is movable in a radial direction with respect to said longitudinal axis toward and away respectively from said external surface, said radially movable member being supported radially outwardly from said support tubular member by said axially movable member and said further member, a taper on a radially outer side from said longitudinal axis on at least one of said axially movable member and said further member, a complementary taper with said taper on a radially inner side of the radially movable member for sliding abutment between said complementary taper and said taper, a radially outer surface of said radially movable member having a pair of oppositely angled tapers facing in opposing longitudinal axial directions, and resilient means for exerting a resilient force on said axially movable member in an axial direction toward said further member to urge said radially movable member along said sliding abutment in a radially outward direction from said longitudinal axis and whereby when a leading one of said oppositely angled tapers meets an obstruction in a central bore of a packer and the reactive force produced therebetween exceeds said resilient force then said radially movable member is thereby urged inwardly so that said sliding abutment moves the axially movable member away from said further member against the force of said resilient means.

A variable outside diameter tool for use in pipewells including a support tubular member for connection to a drilling string, a longitudinal axis of said support tubular member, an external surface of said tubular member supporting a movable member which is arranged to be axially movable along said tubular member and also circumferentially rotatable thereabout, and a further member which is arranged to be circumferentially rotatable about the tubular member and axially spaced from said axially movable member, a radially movable member which is movable in a radial direction with respect to said longitudinal axis toward and away respectively from said external surface, said radially movable member being supported radially outwardly from said tubular member by said axially movable member and said further member, a taper on a radially outer side of said longitundinal axis on at least one of said axially movable member and said further member, a complementary taper with said taper on a radially inner side of the radially movable member for sliding abutment between said complementary taper and said taper, a radially outer surface of said radially movable member having a pair of oppositely angled tapers facing in opposing longitudinal directions, and resilient means for exerting a resilient force on said axially movable member in an axial direction toward said further member to urge said radially movable member along said sliding abutment in a radially outward direction from said longitudinal axis, and whereby when a leading one of said oppositely angled tapers meets an obstruction in a pipewell and the reactive force produced therebetween exceeds said resilient force then said radially movable member is thereby urged inwardly so that said sliding abutment moves the axially movable member away from said further member against the force of said resilient means.

A packer retriever comprising a support tubular member having a longitudinal axis for connection to a drill string by an external screw thread on said support tubular member mating with an internal screw thread on said drill string, a portion of said support tubular member longitudinally adjacent the mating screw threads being located within a bore of said drill string, a generally V-shaped notch formed in an outer wall of said portion of the support tubular member, a locking means inserted through a sidewall of the drill string into a wall of the V-shaped notch to thereby prevent the support tubular member unscrewing from the drill string, an external surface of said support tubular member supporting a movable member which is axially movable therealong, and a further member axially spaced from said movable member, a radially movable member defining a packer catching portion which is movable in a radial direction with respect to said longitudinal axis toward and away respectively from said external surface, said radially movable member being supported radially outwardly from said support tubular member by said axially movable member and said further member, a taper on a radially outer side form said longitundinal axis on at least one of said axially movable member and said further member, a complementary taper with said taper on a radially inner side of the radially movable member for sliding abutment between said complementary taper and said taper, a radially outer surface of said radially movable member having a pair of oppositely angled tapers facing in opposing longitudinal axial directions, and resilient means for exerting a resilient force on said axially movable member in an axial direction toward said further member to urge said radially movable member along said sliding abutment in a radially outward direction from said longitudinal axis and means for adjusting said resilient force whereby when a leading one of said oppositely angled tapers meets an obstruction in a pipewell and the reactive force produced therebetween exceeds said resilient force then said radially movable member is thereby urged inwardly so that said sliding abutment moves the axially movable member away from said further member against the force of said resilient means, and wherein a collapsible sheild is mounted between the radially movable member and the support tubular member for preventing ingress of dirt therebetween.