Downhole tool
AssigneeSpecialised Petroleum Services Group Limited
InventorsGeorge Telfer, Edward Docherty Scott, Rae Andrew Youngor, James Edward Atkins
Life of this patent
Estimating the term…
Abstract
A downhole tool which can perform a task in a well bore, such as circulating fluid radially from the tool. The function is selectively performed by virtue of a sleeve moving within a central bore of the tool. Movement of the sleeve is effected by dropping a ball through a ball seat on the sleeve. Movement of the sleeve is controlled by an index sleeve such that the tool can be cycled back to the first operating position by dropping identical balls through the sleeve. Embodiments are described wherein the balls are deformable, the seat is deformable and the seat provides a helical channel through which the ball passes.
Claims44
A downhole tool for selectively performing a task in a well bore, the tool comprising a substantially cylindrical body having a central bore running axially therethrough, a sleeve located within the bore, the sleeve including a ball seat, a plurality of balls, each ball having substantially similar dimensions and each ball arresting a majority of fluid flow through the bore when located in the ball seat, mechanical biasing means located between the sleeve and the body to bias the sleeve in a first direction, and functional means on the body to perform a task in the well bore, the functional means being operable on relative movement of the sleeve, wherein the functional means has at least a first and a second operating position, each change in position being effected by passing a said ball through the sleeve in a reverse direction, and wherein the said changes form a cyclic pattern such that the functional means can be cycled back to the first operating position.
A method of circulating fluid in a borehole, the method comprising the steps:
- (a) inserting in a work string a tool comprising a tubular body including a plurality of first radial outlets in which is located a sleeve including a plurality of second radial outlets;
- (b) running the work string and tool into a borehole, with the sleeve in a first position relative to the body wherein the first and second radial outlets are arranged in a first operating position;
- (c) dropping a ball into the work string such that the ball lands on the sleeve and forces the sleeve into a second position relative to the body wherein the first and second radial outlets are arranged in an intermediate operating position and fluid flow is restricted by the ball;
- and
- (d) increasing pressure behind the ball to cause the ball to pass through the sleeve, the releasing of pressure caused by the ball passing through the sleeve thereby allowing the sleeve to move to a third position relative to the body wherein the first and second radial outlets are arranged in a second operating position;
- and wherein the ports are aligned in a either of the operating positions and misaligned in the other operating position.
A ball arrester for dissipating momentum of a ball after it has passed through a ball seat, the arrester comprising a substantially cylindrical body in which is located a non-linear pathway through which the ball is guided.
A ball seat for a downhole tool, the ball seat comprising a sleeve formed from a plurality of part cylindrical sleeves which can shuttle with respect to each other, longitudinally in the tool, wherein a ball can only pass through the seat when the part cylindrical sleeves are located at their longitudinal extent.
An actuation mechanism for a downhole tool, the mechanism comprising a substantially cylindrical body having a central bore running axially therethrough, a sleeve located within the bore, the sleeve including a deformable ball seat, mechanical biasing means located between the sleeve and the body to bias the sleeve in a first direction and a ball, wherein the deformable ball seat releasably retains the ball to prevent fluid flow through the sleeve and cause the sleeve to move in the reverse direction relative to the body and wherein on release of the ball the seat returns to its original dimensions.
An actuation mechanism for a downhole tool, the mechanism comprising a substantially cylindrical body having a central bore running axially therethrough, a sleeve located within the bore, the sleeve including a helical channel on an inner surface, mechanical biasing means located between the sleeve and the body to bias the sleeve in a first direction and a ball, sized to run in the helical channel in a reverse direction to prevent a majority of fluid flow through the sleeve and cause the sleeve to move in the reverse direction relative to the body.
A method of circulating fluid in a borehole, the method comprising the steps:
- (a) inserting in a work string a tool comprising a tubular body including a plurality of first radial outlets in which is located a sleeve including a plurality of second radial outlets;
- (b) biasing the sleeve in a first direction towards a first position relative to the body wherein the first and second radial outlets are arranged in a first operating position;
- (c) running the work string and tool into a borehole, with the sleeve in the first position;
- (d) dropping a first ball into the work string such that the ball lands on the sleeve and forces the sleeve in a direction reverse to said first direction into a second position relative to the body wherein the first and second radial outlets are arranged in an intermediate operating position and fluid flow is restricted by the ball;
- (e) increasing pressure behind the first ball to cause the first ball to pass through the sleeve, the releasing pressure allowing the sleeve to move to a third position relative to the body wherein the first and second radial outlets are arranged in a second operating position;
- (f) dropping a second ball of substantially similar dimensions to the first ball into the work string such that the second ball lands on the sleeve and forces the sleeve in said reverse direction back to the second position relative to the body wherein the first and second radial outlets are arranged in the intermediate operating position and fluid flow is restricted by the second ball;
- and
- (g) increasing pressure behind the second ball to cause the second ball to pass through the sleeve, the releasing pressure allowing the sleeve to move back to the first position relative to the body wherein the first and second radial outlets are arranged in the first operating position;
- wherein the first and second radial outlets are aligned in one of the first and second operating positions and misaligned in the other one of the first and second operating positions.
An actuation mechanism for a downhole tool, the mechanism comprising:
- a substantially cylindrical body having a central bore running axially therethrough and a plurality of first radial outlet ports;
- a sleeve located within the bore, the sleeve including a deformable ball seat and a plurality of second radial outlet ports;
- the sleeve being movable relative to the body between a first axial position in which the first and second radial outlet ports are in a first operating position, a second axial position spaced axially from the first axial position in which the first and second radial outlet ports are in an intermediate operating position, and a third axial position spaced axially from both the first and second axial positions in which the first and second radial outlet ports are in a second operating position, wherein the first and second radial outlet ports are aligned in one of the first and second operating positions and misaligned in the other one of the first and second operating positions;
- mechanical biasing means located between the sleeve and the body to bias the sleeve in a first direction;
- and
- a ball;
- wherein the deformable ball seat releasably retains the ball to prevent fluid flow through the sleeve thereby causing the sleeve to move in a reverse direction relative to the body from the first axial position to the second axial position;
- and wherein increasing pressure behind the ball causes the ball to pass through the sleeve such that the biasing means moves the sleeve in the first direction from the second axial position to the third axial position;
- and
- further wherein on release of the ball the seat returns to its original dimensions.
Dependencies are inferred from the claim text.