Downhole tool
A downhole tool, comprising: an inner body, having first and second connections in a drill string to convey fluid from immediately upper to immediately lower components. The inner body defines a flow bore which communicates between the first and second connections. An outer body disposed around at least part of the inner body is axially movable with respect to the inner body, in a direction which is parallel or substantially parallel with a longitudinal axis of the tool, such that introduction of pressurised fluid into pressure chambers tends to drive the outer body axially with respect to the inner body. The tool further comprises a component which is activated or operated by axial movement of the outer body with respect to the inner body.
1 . A downhole tool, comprising:
an inner body, having a first connection to connect the tool to an immediately upper component in a drill string and to receive fluid from the immediately upper component, and a second connection to connect the tool to an immediately lower component in a drill string and to deliver fluid to the immediately lower component, the inner body defining a flow bore therealong which communicates between the first connection and the second connection;
an outer body disposed around at least a part of the inner body;
a plurality of first protrusions extending outwardly from the inner body;
a plurality of second protrusions extending inwardly from the outer body;
a plurality of pressure chambers, each pressure chamber at least partly defined on an inner side by the inner body and on an outer side by the outer body, and at least partly defined on upper and lower sides by one of the first protrusions and one of the second protrusions; and
a plurality of first flow ports, each of the first flow ports allowing fluid communication between the flow bore and one of the pressure chambers, wherein:
the outer body is axially movable with respect to the inner body, in a direction which is parallel or substantially parallel with a longitudinal axis of the tool, such that introduction of pressurised fluid into the pressure chambers tends to drive the outer body axially with respect to the inner body;
one or more blades or cutters which are driven radially inwardly or outwardly by axial movement of the outer body with respect to the inner body, and wherein the blades or cutters are arranged to be driven axially with respect to the inner body by the outer body;
a guide arrangement which guides the blades or cutters to move radially inwardly or outwardly with respect to the inner body when the blades or cutters move axially with respect to the inner body; and
a blade housing, which is connected to the outer body, and is connected to one or more travelling blocks, wherein each blade or cutter can slide radially inwardly and outwardly with respect to the one or more travelling blocks, but is fixed to the one or more travelling blocks in the axial direction.
2 . A tool according to claim 1 , wherein at least one of the pressure chambers is below the component, and at least one of the pressure chambers is above the component.
3 . A tool according to claim 1 , wherein the inner body comprises a plurality of piston inners, and the outer body comprises a plurality of corresponding piston outers, each piston outer at least partially surrounding the corresponding piston inner to form a piston which includes one of the pressure chambers.
4 . A tool according to claim 3 , wherein each piston inner includes an outwardly-protruding flange, which comprises one of the first protrusions.
5 . A tool according to claim 3 , wherein each piston outer includes an inwardly-protruding flange, which comprises one of the second protrusions.
6 . A tool according to claim 1 , wherein the inner body comprises a shaft, which extends continuously between the first connection and the component.
7 . A tool according to claim 6 , wherein the first protrusions comprise piston members that are attached to the shaft.
8 . A tool according to claim 6 , wherein the outer body comprises a plurality of piston outers, each piston outer at least partially surrounding a corresponding one of the first protrusions to form a piston which includes one of the pressure chambers.
9 . A tool according to claim 8 , wherein each piston outer includes an inwardly-protruding flange, which comprises one of the second protrusions.
10 . A tool according to claim 1 , wherein:
the tool has a first configuration, in which the elements are retracted;
the tool has a second configuration, in which the elements are activated, and protrude radially outwardly to a greater extent from a longitudinal axis of the tool than in the first configuration.
11 . A tool according to claim 1 , wherein the pressure chambers comprise at least one first pressure chamber, communicating with the flow bore, wherein the introduction of pressurised fluid into the first pressure chamber tends to drive the outer body axially with respect to the inner body in a first direction, and at least one second pressure chamber, communicating with the flow bore, wherein the introduction of pressurised fluid into the second pressure chamber tends to drive the outer body axially with respect to the inner body in a second direction, which is opposite or substantially opposite to the first.
12 . A tool according to claim 11 , further comprising an isolation arrangement, wherein when the isolation arrangement is activated fluid flow from the first connection to the or each first pressure chamber is blocked or substantially blocked, and fluid may flow from the first connection to the or each second pressure chamber.
13 . A tool according to claim 1 , further comprising a vent allowing fluid flow from the flow bore to an exterior of the tool, and wherein the vent is open at or near the limit of the motion of the outer body with respect to the inner body in a first direction, and closed during other relative positions between the inner and outer body.
14 . A tool according to claim 1 , comprising a latch arrangement which may be moved between an engaged state and a disengaged state, and where when the latch arrangement is in the engaged state, the latch arrangement substantially prevents relative axial movement of the inner body and the outer body.
15 . A tool according to claim 14 , wherein the latch arrangement comprises:
a latch element having a resilient part, the latch element being carried by or fixed in relation to one of the inner body and the outer body;
a receiver having a recess in which a part of the latch element is received, the receiver being carried by, or fixed in relation to, the other one of the inner body and the outer body.
16 . A tool according to claim 15 , wherein the latch arrangement further comprises a blocking component which, in a first position, prevents the resilient part of the latch element from deforming to allow the part of the latch to be removed from the recess, and in a second position does not prevent the resilient part of the latch element from deforming to allow the part of the latch to be removed from the recess.
17 . A downhole tool, comprising:
an inner body, having a first connection to connect the tool to an immediately upper component in a drill string and to receive fluid from the immediately upper component, and a second connection to connect the tool to an immediately lower component in a drill string and to deliver fluid to the immediately lower component, the inner body defining a flow bore therealong which communicates between the first connection and the second connection;
an outer body disposed around at least a part of the inner body;
a plurality of first protrusions extending outwardly from the inner body;
a plurality of second protrusions extending inwardly from the outer body;
a plurality of pressure chambers, each pressure chamber at least partly defined on an inner side by the inner body and on an outer side by the outer body, and at least partly defined on upper and lower sides by one of the first protrusions and one of the second protrusions; and
a plurality of first flow ports, each of the first flow ports allowing fluid communication between the flow bore and one of the pressure chambers, wherein:
the outer body is axially movable with respect to the inner body, in a direction which is parallel or substantially parallel with a longitudinal axis of the tool, such that introduction of pressurised fluid into the pressure chambers tends to drive the outer body axially with respect to the inner body; and
the tool further comprises a component which is activated or operated by axial movement of the outer body with respect to the inner body,
wherein at least one of the pressure chambers is below the component, and at least one of the pressure chambers is above the component.
18 . A downhole tool, comprising:
an inner body, having a first connection to connect the tool to an immediately upper component in a drill string and to receive fluid from the immediately upper component, and a second connection to connect the tool to an immediately lower component in a drill string and to deliver fluid to the immediately lower component, the inner body defining a flow bore therealong which communicates between the first connection and the second connection;
an outer body disposed around at least a part of the inner body;
a plurality of first protrusions extending outwardly from the inner body;
a plurality of second protrusions extending inwardly from the outer body;
a plurality of pressure chambers, each pressure chamber at least partly defined on an inner side by the inner body and on an outer side by the outer body, and at least partly defined on upper and lower sides by one of the first protrusions and one of the second protrusions; and
a plurality of first flow ports, each of the first flow ports allowing fluid communication between the flow bore and one of the pressure chambers, wherein:
the outer body is axially movable with respect to the inner body, in a direction which is parallel or substantially parallel with a longitudinal axis of the tool, such that introduction of pressurised fluid into the pressure chambers tends to drive the outer body axially with respect to the inner body; and
the tool further comprises a component which is activated or operated by axial movement of the outer body with respect to the inner body, wherein:
the tool further comprises a blade carrier, which is connected to the inner body and defines a pocket for each blade;
each blade comprises a blade body having an inclined face at its top end; and
at the top end of each pocket, a corresponding inclined face is formed, which is set at the same, or substantially the same, angle as the inclined face at the top end of the corresponding blade body.
19 . A downhole tool according to claim 18 , wherein each pocket comprises a cut-out section in the cross-sectional shape of the blade carrier, which extends part of the way from the circumference of the blade carrier towards the centre thereof.
20 . A downhole tool according to claim 18 , wherein the pockets are equally radially spaced apart from each other.