GB2457287A

GB2457287A - A drillstring connector

Info

Publication number: GB2457287A
Application number: GB0802406A
Authority: GB
Inventors: George Swietlik
Original assignee: Pilot Drilling Control Ltd
Current assignee: Pilot Drilling Control Ltd
Priority date: 2008-02-08
Filing date: 2008-02-08
Publication date: 2009-08-12
Anticipated expiration: 2028-02-08
Also published as: GB0802406D0; GB2457287B

Abstract

A connector 10 which provides a fluid tight connection between a fluid supply and a drillstring 4, the connector 10 comprising: a piston-rod 20 and a cylinder 15, the piston-rod 20 having a seal 130 at or towards its free end which is adapted to sealingly engage the drillstring 4 when the piston-rod 20 is at least partially extended from the cylinder (15); and a threaded portion 110 provided on the cylinder 15; the threaded portion 110 being adapted to engage with a threaded section in an open end of the drillstring 4; wherein the piston-rod 20 extends through the threaded portion.

Description

A drifistring connector This invention relates to a connector which establishes a fluid tight connection to a drilistring and preferably establishes a fluid tight connection between a drillstring and a top-drive.

Background

It is known in the oil and gas industry to use a top drive motor and a drillstring to drill wells. It is the top drive motor that provides the torque to rotate the drillstring, which in turn rotates the drill bit at the bottom of the well. The drillstring itself consists of a series of hollow pipes, typically 3Oft (9.14m) in length, and these are attached to each other via a threaded connection. More specifically, each pipe is provided with a female thread or "box" at its upper end and a male thread or "pin" at its lower end. The top drive is also attached to the drillstring via a threaded connection.

During the drilling process, drilling-mud is pumped through the connection between the top drive and the drillstring. This drilling-mud travels through the drillstring and ensures sufficient lubrication, cooling and the removal of cuttings. It is often necessary to remove the drillstring from the well (to replace the drill bit for example) and under such circumstances drilling-mud is pumped through the drillstring to displace and support the retreating drilistring and maintain hydraulic balance in the well bore. This ensures that a vacuum is not created and that the force required to remove the drillstring is minimised, allowing the removal to occur more quickly. In a conventional arrangement, the drilling-mud is pumped through the same connection, between the top drive and drilistring, as used when drilling.

When removing a drillstring from a well (which in the industry is known as tripping-out), successive sections of the drillstring have to be disconnected from the remaining sections of the drillstring. Furthermore, the section being removed also has to be disconnected from the top drive. A new connection is then established between the top drive and the remaining sections of the drillstring. However, making and breaking these threaded connections is very time consuming and slows down the process of removing a drillstring from a well. This has a serious impact on the productivity of the well.

Previous attempts have been made at speeding up the process of tripping-out GB21 56402A discloses methods for controlling the rate of withdrawal and the drilling-mud pressure to maximise the tripping-out speed. However, the time taken to connect and disconnect each section of the drillstring to the top drive is not addressed. Other attempts include removing several sections at a time, as discussed in GB21 56402A.

However, this approach is limited by the height of the derrick holding the top drive.

GB2435059A discloses a device which comprises an extending piston-rod with a bung, which is selectively engaged with the top of the drillstring to provide a fluid tight seal between the drillstring and top drive. This arrangement obviates the need for threading and unthreading the drillstring to the top drive. However, the device disclosed cannot transmit a torque from the top drive to the drillstring and as such must be removed from the lop drive if the drilistring requires turning.

In other applications, it is often desirable to displace fluid from the borehole, particularly when lowering the drillstring, for example, in deep water drilling applications. In such deep water applications the seabed accommodates equipment to support the construction of the well and the tubing used to line the well bore is hung and placed from this position. This is carried out by using a drillstring as a means of conveying and landing the tubing into position and as the drillstring is lowered, successive sections of drilistring have to be added. It would therefore be desirable to use a device similar to that disclosed in GB2435059A to minimise the number of threaded connections required. However, in such an application it may be desirable to rotate the casing as it is landed in order to prevent the casing sticking to the weilbore.

Furthermore, as described above, it is desirable that the device disclosed in GB2435059A could be used in a range of applications and a more versatile tool is therefore required. The present invention seeks to address these issues.

Statements of Invention

According to a first aspect of the present invention, there is provided a connector which provides a fluid tight connection between a fluid supply and a drillstring, the connector comprising: a piston-rod and a cylinder, the piston-rod having a seal at or towards its free end which is adapted to sealingly engage the drillstring when the piston-rod is at least partially extended from the cylinder; and a threaded portion provided on the cylinder; the threaded portion being adapted to engage with a threaded section in an open end of the drillstring; wherein the piston-rod extends through the threaded portion The seal between the connector and the drillstring may be provided by the location of a tapered bung in the open end of the drifistring. The seal may be detachable from the piston-rod. The seal may be interchangeable with one or more alternative seals. The connector may connect to the drillstring via the threaded portion engaging with a corresponding threaded section in the open end of the drillstring.

The seal may be provided on a shaft, the shaft being detachable from the piston-rod.

The shaft may be threadably engaged with the piston-rod. The shaft may be threadably engaged to the piston-rod with a stub-acme connection.

A connection between the piston-rod and shaft may act as a sacrificial connection such that if an impact load is applied to the shaft, the piston-rod and cylinder may be protected. The connection between the piston-rod and shaft may be box weak.

The piston-rod may be retractable within the threaded portion, so that when the seal is detached the piston-rod may not be exposed beyond the end of the threaded portion.

The piston-rod may fit inside the interior of the drillstring beyond the threaded section in the open end of the drillstring. The piston-rod may be provided with a mechanical stop limiting the retraction of the piston-rod into the cylinder.

The piston-rod may provide a flow communication path between the fluid supply and the drillstring. The piston-rod may be hollow and the shaft may be hollow.

The threaded portion may be provided on a threaded member disposed about the piston-rod and the threaded member may be detachable from the cylinder. The threaded member may be threadably engaged with the cylinder. The threaded member may be interchangeable with one or more alternative threaded members.

The piston-rod may be provided with a keyway. The threaded member may be provided with a key and the key may interface with the keyway of the piston-rod so that rotation of the piston-rod may be prevented. The key and keyway may provide the mechanical stop limiting the retraction of the piston-rod.

The threaded member may be provided with a port and the port may act as a vent for fluid displaced in the cylinder by movement of the piston-rod.

The connector may be capable of transmitting torque from a top-drive to the drilistring via the threaded portion engaging with the threaded section of the drillstring. All threaded connections may be orientated in the same direction. The threaded portion may comprise a standard pin connection. The threaded section in the open end of the drilistring may comprise a standard box connection.

According to a second aspect of the present invention, there is provided a connector which provides a fluid tight connection between a fluid supply and a drillstring, the connector comprising: a hydraulic ram comprising a piston-rod and a cylinder, the piston-rod having a seal at or towards its free end which is adapted to sealingly engage the drilistring when the piston-rod is at least partially extended from the cylinder; and a threaded portion provided on the cylinder; the threaded portion being adapted to engage with a threaded section in an open end of the drilistring; wherein the seal is detachable from the piston-rod.

According to a third aspect of the present invention, there is provided a connector which provides a fluid tight connection between a fluid supply and a drillstring, the connector comprising: a hydraulic ram comprising a piston-rod and a cylinder, the piston-rod having a seal at or towards its free end which is adapted to sealingly engage the drilistring when the piston-rod is at least partially extended from the cylinder; and a threaded portion provided on the cylinder; the threaded portion being adapted to engage with a threaded section in an open end of the drillstring; wherein the threaded portion is provided on a threaded member disposed about the piston-rod, the threaded member being detachable from the cylinder.

According to a fourth aspect of the present invention, there is provided a connector which provides a fluid tight connection between a fluid supply and a drillstring, the connector comprising: a piston-rod and a cylinder, the piston-rod having a seal at or towards its free end which is adapted to sealingly engage the drilistring when the piston-rod is at least partially extended from the cylinder; and a threaded portion provided on the cylinder; the threaded portion being adapted to engage with a threaded section in an open end of the drillstring; wherein the piston-rod and the cylinder form an hydraulic ram.

According to a fifth aspect of the present invention, there is provided a connector which provides a fluid tight connection between a fluid supply and a drillstring, the connector comprising: a piston-rod and a cylinder, the piston-rod having a seal at or towards its free end which is adapted to sealingly engage the drillstring when the piston-rod is at least partially extended from the cylinder; wherein the seal is detachable from the piston-rod.

Preferably, the seal is fixed to a detachable shaft, which is mounted to the piston-rod.

Preferably, the detachable shaft is connected to the piston-rod by means of a threaded connection.

According to a sixth aspect of the present invention, there is provided a connector which provides a fluid tight connection between a fluid supply and a drillstring, the connector comprising: a piston-rod and a cylinder, the piston-rod having a seal at or towards its free end which is adapted to sealingly engage the drillstring when the piston-rod is at least partially extended from the cylinder; and a threaded portion provided on the cylinder; the threaded portion being adapted to engage with a threaded section in an open end of the drillstring with the seal in engagement with the drill string.

Brief Description of the Drawings

For a better understanding of the present invention, and to show more clearly how it may be carried into effect, reference will now be made, by way of example, to the following drawings, in which: Figure 1 is a schematic of the connector and shows the connector in position between the top drive and the drilistring; Figures 2a and 2b are sectional side projections of the connector according to a first embodiment of the invention and show the connector in a retracted position (Figure 2a) and in an extended position (Figure 2b); Figures 3a and 3b are more detailed sectional views of the connector according to a first embodiment of the invention and show the connector in a retracted position (Figure 3a) and a concealed position (Figure 3b); Figure 4 is a representation of the sealing arrangement; and Figure 5 is a representation of the threaded member.

Detailed Description of the Preferred Embodiment

With reference to Figure 1, a drillstring 4 is lowered into a well by lowering a top drive 2 In a conventional arrangement, the top-most section 3 of the drillstring 4 is provided with a female thread, which directly engages a male threaded connector 5 on the top drive 2 to provide a connection to allow drilling-mud to be pumped into or from the drillstring 4. Once a section of the drillstring 4 is lowered into the well it must then be disconnected from the top drive 2 before the next section can be added to the drilistring. Making and breaking the threaded connection between the top drive and drillstring is time consuming, particularly when lowering an entire drillstring 4 section by section to below the seabed when deep sea drilling. The present invention therefore relates to an alternative means for establishing this connection. This alternative connection is achieved via a connector 10, which is placed between the top drive 2 and drillstring 4.

With reference to Figures 2a and 2b, a connector 10, according to the present invention, comprises a cylinder 15 and a piston-rod 20, the piston-rod 20 being slidably engaged in the cylinder 15. The piston-rod 20 further comprises a hollow tubular 30, the tubular 30 being slidably engaged in the cylinder 15 such that a first end of the tubular 30 protrudes outside the cylinder 15 and a second end is within the cylinder 15.

The tubular 30 is also disposed about a hollow shaft 16, the shaft 16 being disposed within the cylinder 15. The tubular 30, cylinder 15 and shaft 16 are arranged such that their longitudinal axes are coincident and the tubular 30 is slidably disposed about the shaft 16 such that the piston-rod 20 telescopically extends through the cylinder 15 from a retracted position to an extended position. Figure 2a shows the piston-rod 20 in its retracted position, whilst figure 2b shows the piston-rod 20 in its extended position On a first end of the tubular 30 there is located a bung 60 with seals 130. The bung 60 and/or seals 130 may be made from a resilient and/or elastomeric material such as rubber or nylon and is shaped to fit into the top end of a drillstring 4. The bung 60 and seals 130 engage the top end of a drillstring 4 when the piston-rod 20 is in its extended position, thereby providing a fluid tight seal between the connector 10 and drillstring 4.

For example, the bung 60 and/or seals may seal on, in or around a box at the top end of the drillstring 4.

At a first end of the cylinder 15 there is provided a first end plug 42, through which the tubular 30 protrudes. The first end plug 42 is threaded to the first end of the cylinder 15. A threaded member 110 is then provided on the first end plug 42. The threaded member 110 is connected to the first end plug 42 by virtue of a threaded connection and the threaded member 110 is hollow to allow the tubular 30 to pass through it. The threaded member 110 seals the inside of the cylinder 15 from the outside, whilst also allowing the tubular 30 to slide in or out of the cylinder 15. Seals, such as 0-ring seals may be used to seal between the first end plug 42 and tubular 30.

At the opposite end of the cylinder 15 to the threaded member 110, there is provided a socket 25 for engagement with the top drive 2. The socket 25 comprises a female threaded connection which may be in the form of a conventional box and which threads onto a corresponding thread (or pin) on the top drive 2. The top drive 2 provides drilling fluid to the cylinder 15 through the socket 25. Between the first and second ends of the cylinder 15 there is provided a valving assembly 200, which manages the flow of drilling fluid from the top drive 2 to the drill string 4.

The piston-rod 20 further comprises a piston 50 disposed at a second end of the tubular 30. The piston 50 is slidably mounted on the tubular 30 inside the cylinder 15 and is free to move between the first end plug 42 and a second end plug 40. The second end plug 40 is threaded into the cylinder 15 and threaded onto the shaft 16 such that the hollow centre of the shaft 16 continues through the second end plug 40.

The inside of the cylinder 15 is divided by the piston 50 to form a first chamber 60 and a second chamber 70. The first end plug 42, cylinder 15, tubular 30 and piston 50 define the first chamber and an end-face 41, cylinder 15, shaft 16 and piston 50 define the second chamber 70. The piston 50 is fixedly attached to the tubular 30 and is sealed against the inside of cylinder 15 and the outside of shaft 16, for example by means of 0-ring seals 52 and 54, to ensure no flow communication between the two chambers 70 and 80.

Retraction of the piston-rod 20 is limited by the bung 60 impinging against the threaded member 110 and the extension of the piston-rod 20 is limited by an annular shoulder 114 in the tubular 30 engaging with an annular abutment surface 116 in the threaded member 110. The annular shoulder 114, annular abutment surface 116, bung 60 and threaded member 110 thereby act as mechanical stops. An atmospheric vent 112 is provided in the threaded member 110 between the annular shoulder 114 and the annular abutment surface 116 to ensure that movement of the tubular 30 is not resisted by air trapped therebetween. Retraction of the piston-rod 20 is also limited by a second annular shoulder 115, which is disposed inside the piston-rod 20, such that the second annular shoulder abuts an end of the shaft 16. To avoid a pressure lock from occurnng, the volume of fluid displaced by the movement of the second annular shoulder 115 is preferably equal to the volume of fluid displaced by the piston-rod 20 as it extends into the drillstring 4.

In the first embodiment of the invention, the first and second chambers 80 and 70 are provided with pressurised air via an air supply (not shown). The first chamber 80 is in flow communication with the air supply via a first supply port 100 and the second chamber 70 is in flow communication with the air supply via a second supply port 90.

In the first embodiment of the invention, a valve 118 is provided between the first and second supply ports 100, 90, the valve 118 is also connected to the air supply and the atmosphere. The valve 118 in an exemplary embodiment comprises a four-way cross port valve for selectively connecting the first and second supply ports 100, 90 to the air supply and the second and first supply ports 90, 100 respectively to the atmosphere.

In alternative embodiments the first and second chambers 80, 70 may be pressurised with a fluid other than air and the valve 118 may comprise an alternative valve system for selectively pressurising the first and second chambers 80, 70.

In operation the air supply selectively provides pressurised air to either the first chamber 80 or the second chamber 70, via valve 118, and the other of the first or second chambers 80, 70 is vented to the atmosphere, again via valve 118. A pressure differential is therefore created across the piston 50 and the piston-rod 20 extends when the force acting on the piston 50 due to air pressure in the first chamber 80 is higher than the force acting on the piston 50 due to the air pressure in the second chamber 70 (figure 2b). Conversely, the piston-rod 20 retracts when the force acting on the piston 50 due to air pressure in the second chamber 70 is higher than the force acting on the piston 50 due to the air pressure in the first chamber 70 (figure 2a).

With reference to Figure 3a, the bung 60, according to the present invention, further comprises a detachable shaft 105. The detachable shaft 105 is threadably attached to the tubular 30 and is selectively detachable from the tubular 30. The seals 130 are provided around the outside of the detachable shaft 105. The detachable shaft 105 is hollow to allow the flow of drilling fluid from the top drive 2, through the shaft 16 and tubular 15, and into the top of the drillstring 4.

The detachable shaft 105 and attached seals 130 are interchangeable with alternative shaft and seal arrangements. This facilitates the repair and replacement of worn seals, or differently shaped bungs could be deployed for different drilistrings. Furthermore, the connection between the tubular 30 and the detachable shaft 105 can be made deliberately weak, so that it acts as a sacrificial connection. If an impact load is applied to the bung 60 the connection will tend to fail, so that the piston-rod 20 and cylinder 15 are protected from damage. For example, the detachable shaft 105 may be provided with a female threaded socket, which engages with a corresponding male thread on the tubular 30, and the female threaded socket of the detachable shaft 105 may be deliberately weakened at its root so that it will fail before damage occurs to the tubular The end of the detachable shaft 105, which attaches to the tubular 30, has the same or smaller external dimensions as the tubular 30. This ensures that the detachable shaft fits inside the threaded member 110. Furthermore, the detachable shaft 105 has a protrusion 106, which acts as a mechanical stop limiting the retraction of the piston-rod into the cylinder 15. The protrusion 106 is shaped with spanner flats so that the detachable shaft 105 can be removed from the tubular 30.

With reference to Figure 3b, the tubular 30, according to the present invention, further comprises an abutment shoulder 150, which is formed by a flat portion on the outer surface of the tubular 30 being adjacent to a cylindrical portion The flat portion on the surface of the tubular 30 provides a keyway and the threaded member 110 is provided with a corresponding key 160. The key 160 interfaces with the keyway of the tubular so that rotation of the tubular 30 is prevented, thereby facilitating removal of the detachable shaft 105. Furthermore, the tubular 30 may be fully retractable within the threaded member 110 when the detachable shaft 105 is removed, such that the tubular 30 does not extend beyond the end of the threaded member 110. The key 160 and keyway also provide a mechanical stop limiting the retraction of the piston-rod 20 when the detachable shaft 105 is removed.

The threaded member 110 is further provided with a threaded section 170. In one mode of operation the threaded section 170 is threadably connected to the open end of the drillstring 4 and the connector 10 is therefore capable of transmitting torque from the top-drive 2 to the drillstring 4. Accordingly, in order to transmit drive, the threaded connections between the top-drive 2, socket 25, threaded member 110 and drillstring 4 are orientated in the same direction.

The detachable shaft 105 and hence bung 60 are removed from the tubular 30 when the threaded member 110 is connected to the drillstring 4. The tubular 30 is sized so that it fits inside the interior of the drillstring beyond the threaded section in the open end of the drillstring. Alternatively, the tubular 30 may also be retracted into the threaded member 110.

In an alternative embodiment, the detachable shaft 105 need not be removed from the tubular 30 when threading the threaded member 110 to the drillstring. The connector may then connect to the drilistring by virtue of both the bung 60 and the threaded member 110. Such an alternative embodiment would allow rapid deployment of the threaded connection without having to remove the detachable shaft 105, thereby saving time and money. In order to enable the engagement of the threaded member with the drillstring 4 without removing the detachable shaft 105, the protrusion may be smaller than the protrusion 106 shown in figure 3a. For example, the protrusion may not extend radially outwardly beyond the radially outer surface of the bung 60.

The threaded member 110 is removable from the first end cap 42 and as such is interchangeable with alternative threaded members. This facilitates repair of the threaded member 110 and/or enables differently shaped threaded members to be deployed to suit the particular drillstring 4 in use.

Figures 4 and 5 are representations of the bung 60 and the threaded member 110 respectively showing the features mentioned above in perspective view.

In operation, the connector 10 is connected to the top drive 2 and the top drive 2 is lowered to a suitable position, so that the connector can reach the open end of the drillstring 4. Once the top drive 2 and connector 10 are in place, the piston-rod 20 is extended by increasing the pressure in the second chamber 70. The bung 60 is then located in the box at the end of the drillstring 4 and a fluid tight seal is provided by the seals 130. The elevators 6 can then engage the drillstring 4 and the slips (not shown) can be released. The drillstring 4 can then be lifted from the well.

The top drive 2 pumps drilling fluid through the socket 25, which connects the top drive 2 to the connector 10 and ultimately into the passage defined by the hollow shaft 16.

The drilling fluid then flows into the extended tubular 30 and into the drillstring 4, thereby replacing the volume displaced by the drillstring 4 as it is retracted from the well When a sufficient section of the drillstring 4 is clear of the well (one or more sections may be removed at a time), the slips will reengage with the drillstring 4 and the flow of drifling fluid from the top drive 2 will be stopped. The valving arrangement 200 will then move to a closed position. The piston-rod 20 can then be retracted from the drillstring 4 by increasing the pressure in the first chamber 80 without leaking any drilling fluid from the top drive 2. The exposed section of the drillstring 4 can then be removed from the rest of the drillstring remaining in the well and the process described above can be repeated.

Alternatively, the above procedure can be applied in reverse when lowering a drill string or other tubular into the well.

As previously mentioned, the connector 10 replaces the traditional threaded connection between a top drive 2 and drillstring 4 during the removal of a drillstring 4 from a well.

With this connector, the connection between the top drive 2 and drillstring 4 can therefore be established in a much shorter time and great savings can be achieved.

The above-mentioned features provide a more versatile connector. The connector 10 can stay connected to the top drive 2 when a direct connection to the drillstring 4 is required to turn the drillstring 4. Rather than removing the entire connector 10, the detachable shaft 105 can be quickly removed from the tubular 30 and the connector 10 may engage directly with the drill string 4 by virtue of the threaded section 170 on the threaded member 110. This facility saves time and hence money in drilling applications.

Claims

Claims 1. A connector which provides a fluid tight connection between a fluid supply and a drilistring, the connector comprising: a piston-rod and a cylinder, the piston-rod having a seal at or towards its free end which is adapted to sealingly engage the drilistring when the piston-rod is at least partially extended from the cylinder; and a threaded portion provided on the cylinder; the threaded portion being adapted to engage with a threaded section in an open end of the drilistring; wherein the piston-rod extends through the threaded portion.
2. A connector as claimed in claim 1, wherein the seal between the connector and the drillstring is provided by the location of a tapered bung in the open end of the drillstring.
3. A connector as claimed in claim 1 or 2, wherein the connector connects to the drillstring via the threaded portion engaging with a corresponding threaded section in the open end of the drilistring.
4. A connector as claimed in any preceding claim, wherein the seal is detachable from the piston-rod.
5. A connector as claimed in claim 4, wherein the seal is provided on a shaft, the shaft being detachable from the piston-rod.
6. A connector as claimed in claim 5, wherein the shaft is threadably engaged with the piston-rod.
7. A connector as claimed in claims 5 or 6, wherein a connection between the piston-rod and shaft acts as a sacrificial connection such that if an impact load is applied to the shaft, the piston-rod and cylinder are protected.
8 A connector as claimed in any one of claims 4 to 7, wherein the seal is interchangeable with one or more alternative seals.
9 A connector as claimed in any one of claims 4 to 8, wherein the piston-rod is retractable within the threaded portion, so that when the seal is detached the piston-rod is not exposed beyond the end of the threaded portion.
10 A connector as claimed in any preceding claim, wherein the piston-rod fits inside the interior of the drilistring beyond the threaded section in the open end of the drillstring.
11 A connector as claimed in any preceding claim, wherein the piston-rod is provided with a mechanical stop limiting the retraction of the piston-rod into the cylinder.
12. A connector as claimed in any preceding claim, wherein the piston-rod provides a flow communication path between the fluid supply and the drillstring.
13 A connector as claimed in any preceding claim, wherein the piston-rod is hollow.
14. A connector as claimed in claims 5, 6 or 7, wherein the shaft is hollow.
15 A connector as claimed in any preceding claim, wherein the threaded portion is provided on a threaded member disposed about the piston-rod, the threaded member being detachable from the cylinder.
16. A connector as claimed in claim 15, wherein the threaded member is threadably engaged with the cylinder.
17 A connector as claimed in claim 15 or 16, wherein the threaded member is interchangeable with one or more alternative threaded members.
18 A connector as claimed in any preceding claim, wherein the piston-rod us provided with a keyway.
19 A connector as claimed in claim 15, 16 or 17 and 18, wherein the threaded member is provided with a key, the key interfacing with the keyway of the piston-rod so that rotation of the piston-rod is prevented.A connector as claimed in claims 11 and 19, wherein the key and keyway provide the mechanical stop limiting the retraction of the piston-rod.
21 A connector as claimed in any one of claims 15 to 20, wherein the threaded member is provided with a port, the port acting as a vent for fluid displaced in the cylinder by movement of the piston-rod.
21. A connector as claimed in any preceding claim, wherein the connector is capable of transmitting torque from a top-drive to the drillstring via the threaded portion 1 0 engaging with the threaded section of the drillstring.
22 A connector as claimed in any preceding claim, wherein all threaded connections are orientated in the same direction.
23. A connector as claimed in any preceding claim, wherein the threaded portion comprises a standard pin connection.

24 A connector as claimed in claim 3, wherein the threaded section in the open end of the drillstring comprises a standard box connection.

A kit of parts for a connector which provides a fluid tight connection between a fluid supply and a drilistring, the kit of parts comprising: a piston-rod and a cylinder, the piston-rod having a seal at or towards its free end which is adapted to sealingly engage the drilistring when the piston-rod is at least partially extended from the cylinder: and a threaded portion provided on the cylinder; the threaded portion being adapted to engage with a threaded section in an open end of the drillstring; wherein the piston-rod extends through the threaded portion.

26 A kit of parts for a connector as claimed in claim 25, wherein the seal is removable and interchangeable and the kit further comprising at least one additional removable and interchangeable seal, the seals having a different shape and/or size.

27 A kit of parts for a connector as claimed in claims 25 or 26, wherein the threaded portion is removable and interchangeable and the kit further comprising at least one additional removable and interchangeable threaded portion, the threaded portions having a different shape and/or size and/or thread.

28 A connector for interfacing with a drill-string, substantially as described herein with reference to and as shown in the accompanying drawings.