WO2009098473A2

WO2009098473A2 - Hydraulic connector apparatuses and methods of use with downhole tubulars

Info

Publication number: WO2009098473A2
Application number: PCT/GB2009/000338
Authority: WO
Inventors: George Swietlik; Robert Large
Original assignee: Pilot Drilling Control Limited
Priority date: 2008-02-08
Filing date: 2009-02-09
Publication date: 2009-08-13
Also published as: EP2255059A1; WO2009098478A3; EP2255059B1; BRPI0905957A2; WO2009098478A2; WO2009098482A1; ATE530730T1; GB2457317A; WO2009098473A3; GB0805299D0; WO2009098474A1; CA2715073A1

Abstract

A hydraulic connector to provide a fluid tight connection between a fluid supply and a downhole tubular includes an engagement assembly configured to extend and retract a seal assembly disposed at a distal end of the hydraulic connector into and from a proximal end of the downhole tubular, and a valve assembly operable between an open position and a closed position, wherein the valve assembly is configured to allow the fluids to communicate between the fluid supply and the downhole tubular through the seal assembly when in the open position, and wherein the valve assembly is configured to prevent fluid communication between the fluid supply and the downhole tubular when closed position.

Description

HYDRAULIC CONNECTOR APPARATUSES /VND METHODS OF USE WITH DOVYNHOLE TUBULARS

BACKGROUND OF THE DISCLOSURE Field of the Disclosure

[0001] The present disclosure generally relates to a connector establishing a fluid-tight connection to a downhole tubular. More particularly, the present disclosure relates to a connector establishing a fluid-tight connection between a downhole tubular and a lifting assembly. Alternatively, the present disclosure relates to a connector establishing a fluid- tight connection between a downhole tubular and another tubular.

Description of the Related Art

[0002] It is known in the industry to use a top-drive assembly to apply rotational torque to a series of inter-connected tubulars (commonly referred to as a drillstring comprised of drill pipe) to drill subterranean and subsea oil and gas wells. In other operations, a top- drive assembly may be used to install casing strings to already drilled wellbores. The top-drive assembly may include a motor, either hydraulic, electric, or other, to provide the torque to rotate the drillstring, which in turn rotates a drill bit at the bottom of the well.

[0003] Typically, the drillstring comprises a series of threadably-connected tubulars (drill pipes) of varying length, typically about 30ft (9.14m) in length. Typically, each section, or "joint" of drill pipe includes a male-type "pin" threaded connection at a first end and a corresponding female-type "box" threaded connection at the second end. As such, when making-up a connection between two joints of drill pipe, a pin connection of the upper piece of drill pipe (i.e., the new joint of drill pipe) is aligned with, threaded, and torqued within a box connection of a lower piece of drill pipe (i.e., the former joint of drill pipe). In a top-drive system, the top-drive motor may also be attached to the top joint of the drillstring via a threaded connection.

[0004] During drilling operations, a substance commonly referred to as drilling mud is pumped through the connection between the top-drive and the drillstring. The drilling mud travels through a bore of the drillstring and exits through nozzles or ports of the drill bit or other drilling tools downhole. The drilling mud performs various functions, including, but not limited to, lubricating and cooling the cutting surfaces of the drill bit. Additionally, as the drilling mud returns to the surface through the annular space formed between the outer diameter of the drillstring and the inner diameter of the borehole, the mud carries cuttings away from the bottom of the hole to the surface. Once at the surface, the drill cuttings are filtered out from the drilling mud and the drilling mud may be reused and the cuttings examined to determine geological properties of the borehole.

[0005] Additionally, the drilling mud is useful in maintaining a desired amount of head pressure upon the downhole formation. As the specific gravity of the drilling mud may be varied, an appropriate "weight" may be used to maintain balance in the subterranean formation. If the mud weight is too low, formation pressure may push back on the column of mud and result in a blow out at the surface. However, if the mud weight is too high, the excess pressure downhole may fracture the formation and cause the mud to invade the formation, resulting in damage to the formation and loss of drilling mud.

[0006] As such, there are times (e.g., to replace a drill bit) where it is necessary to remove (i.e., "trip out") the drillstring from the well and it becomes necessary to pump additional drilling mud (or increase the supply pressure) through the drillstring to displace and support the volume of the drillstring retreating from the wellbore to maintain the well's hydraulic balance. By pumping additional fluids as the drillstring is tripped out of the hole, a localized region of low pressure near or below the retreating drill bit and drill pipe (i.e., suction) may be reduced and any force required to remove the drillstring may be minimized. In a conventional arrangement, the excess supply drilling mud may be pumped through the same connection, between the top-drive and drillstring, as used when drilling.

[0007] As the drillstring is removed from the well, successive sections of the retrieved drillstring are disconnected from the remaining drillstring (and the top-drive assembly) and stored for use when the drillstring is tripped back into the wellbore. Following the removal of each joint (or series of joints) from the drillstring, a new connection must be established between the top-drive and the remaining drillstring. However, breaking and re-making these threaded connections, two for every section of drillstring removed, is very time consuming and may slow down the process of tripping out the drillstring.

[0008] Previous attempts have been made at speeding up the process of tripping-out.

GB2156402 A discloses methods for controlling the rate of withdrawal and the drilling mud pressure to maximize the speed of tripping-out the drillstring. However, the amount of time spent connecting and disconnecting each section of the drillstring to and from the top-drive is not addressed.

[0009] Another mechanism by which the tripping out process may be sped up is to remove several joints at a time (e.g., remove several joints together as a "stand"), as discussed in GB2156402A. By removing several joints at once in a stand (and not breaking connections between the individual joints in each stand), the total number of threaded connections that are required to be broken may be reduced by 50-67%. However, the number of joints in each stand is limited by the height of the derrick and the pipe rack of the drilling rig, and the method using stands still does not address the time spent breaking the threaded connections that must still be broken.

[0010] GB2435059A discloses a device which comprises an extending piston-rod with a bung, which may be selectively engaged within 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, a problem with the device disclosed therein is that the extension of the piston-rod is dependent upon the pressure and flow of the drilling mud through the top-drive. Whilst this may be advantageous in certain applications, a greater degree of control over the piston-rod extension independent of the drilling mud pressure is desirable.

[0011] Similarly, there may be applications where it is desirable to displace fluid from the borehole, particularly, for example, when lowering the drillstring (or a casing-string) in deepwater drilling applications. In such deepwater applications, the seabed accommodates equipment to support the construction of the well and the casing used to line the wellbore may be hung and placed from the seabed. In such a configuration, a drillstring (from the surface vessel) may be used as the mechanism to convey and land the casing string into position. As the drillstring is lowered, successive sections of drillstring would need to be added to lower the drillstring (and attached casing string) further. However, as the bore of the typical drillstring is much smaller than the bore of a typical string of casing, fluid displaced by the casing string will flow up and exit through the smaller-bore drillstring, at increased pressure and flow rates. As such, designs such as those disclosed in GB2435059A would not allow reverse flow of drilling mud (or seawater) as would be required in such a casing installation operation.

[0012] Embodiments of the present disclosure seek to address these and other issues of the prior art.

SUMMARY OF THE CLAIMED SUBJECT MATTER

[0013] In one aspect, the present disclosure relates to a hydraulic connector to provide a fluid tight connection between a fluid supply and a downhole tubular including an engagement assembly configured to extend and retract a seal assembly disposed at a distal end of the hydraulic connector into and from a proximal end of the downhole tubular, and a valve assembly operable between an open position and a closed position, wherein the valve assembly is configured to allow the fluids to communicate between the fluid supply and the downhole tubular through the seal assembly when in the open position, and wherein the valve assembly is configured to prevent fluid communication between the fluid supply and the downhole tubular when closed position.

[0014] In another aspect, embodiments of the present disclosure relate to a hydraulic connector to provide a fluid tight connection between a fluid supply and a downhole tubular including a body portion, an extendable portion recriprocable with respect to the body portion, and a seal assembly at a distal end of the extendable portion, wherein the seal assembly is configured to sealingly engage the downhole tubular, and wherein the seal assembly is detachable from the extendable portion.

[0015] In another aspect, embodiments of the present disclosure relate to a method to provide a fluid tight connection between a fluid supply and a downhole tubular using a hydraulic connector including disposing a seal assembly upon a distal end of a piston-rod assembly, increasing a pressure of fluids in the fluid supply, extending the piston-rod assembly, and engaging the seal assembly within a proximal end of the downhole tubular, engaging at least one of the seal assembly and a threaded member within a proximal end of the downhole tubular.

BRIEF DESCRIPTION OF DRAWINGS

[0016] Features of the present disclosure will become more apparent from the following description in conjunction with the accompanying drawings.

[0017] Figures Ia and Ib schematically depict a connector in accordance with embodiments of the present disclosure and depicts the connector in position between a top-drive and a downhole tubular.

[0018] Figure 2 is a sectional side projection of a connector in accordance with embodiments disclosed herein showing the connector prior to engagement with the string of downhole tubulars.

[0019] Figure 3 is a sectional side projection of the connector of Figure 2 in an engaged position.

[0020] Figures 4a and 4b are more detailed sectional views of a sealing assembly of the connector according to embodiments of the present disclosure.

[0021] Figure 5 is a profiled representation of a sealing arrangement in accordance with embodiments disclosed herein.

[0022] Figure 6 is a profiled representation of a threaded member in accordance with embodiments disclosed herein.

[0023] Figures 7a and 7b show perspective sectional views of a protector cap usable with a hydraulic connector in accordance with embodiments disclosed herein.

[0024] Figure 8a is a side view of a connector in accordance with embodiments disclosed herein and Figure 8b is a sectional side view of section A-A shown in Figure 6a. [0025] Figures 9a and 9b show perspective views of a locking feature for hydraulic connectors in accordance with embodiments disclosed herein.

DETAILED DESCRIPTION

[0026] Select embodiments describe a tool to direct fluids from a top-drive (or other lifting) assembly and a bore of a downhole tubular. In particular, the tool may include an engagement assembly to extend a seal assembly into the bore of the downhole tubular, a valve assembly to selectively allow pressurized fluids from the top-drive assembly to enter the downhole tubular, and a reverse flow valve assembly to selectively allow pressurized fluids from the downhole tubular to flow toward the top- drive assembly within the tool.

[0027] Referring initially to Figures Ia and Ib (collectively referred to as "Figure 1"), a top-drive assembly 2 is shown connected to a proximal end of a string of downhole tubulars 4. As shown, top-drive 2 may be capable of raising ("tripping out") or lowering ("tripping in") downhole tubulars 4 through a pair of lifting bales 6, each connected between lifting ears of top-drive 2, and lifting ears of a set of elevators 8. When closed (as shown), elevators 8 grip downhole tubulars 4 and prevent the string from sliding further into a wellbore 26 (below).

[0028] Thus, the movement of string of downhole tubulars 4 relative to the wellbore 26 may be restricted to the upward or downward movement of top-drive 2. While top- drive 2 (as shown) must supply any upward force to lift downhole tubular 4, downward force is sufficiently supplied by the accumulated weight of the entire free-hanging string of downhole tubulars 4, offset by their accumulated buoyancy forces of the downhole tubulars 4 in the fluids contained within the wellbore 26. Thus, as shown, the top-drive assembly 2, lifting bales 6, and elevators 8 must be capable of lifting (and holding) the entire free weight of the string of downhole tubulars 4.

[0029] As shown, string of downhole tubulars 4 may be constructed as a string of threadably connected drill pipes (e.g., a drillstring 4), may be a string of threadably connected casing segments (e.g., a casing string 7), or any other length of generally tubular (or cylindrical) members to be suspended from a rig derrick 12. In a conventional drillstring or casing string, the uppermost section {i.e., the "top" joint) of the string of downhole tubulars 4 may include a female- threaded "box" connection 3. In some applications, the uppermost box connection 3 is configured to engage a corresponding male-threaded ("pin") connector 5 at a distal end of the top-drive assembly 2 so that drilling-mud or any other fluid {e.g., cement, fracturing fluid, water, etc.) may be pumped through top-drive 2 to bore of downhole tubulars 4. As the downhole tubular 4 is lowered into a well, the uppermost section of downhole tubular 4 must be disconnected from top-drive 2 before a next joint of string of downhole tubulars 4 may be threadably added.

[0030] As would be understood by those having ordinary skill, the process by which threaded connections between top-drive 2 and downhole tubular 4 are broken and/or made-up may be time consuming, especially in the context of lowering an entire string {i.e., several hundred joints) of downhole tubulars 4, section-by-section, to a location below the seabed in a deepwater drilling operation. The present disclosure therefore relates to alternative apparatus and methods to establish the connection between the top- drive assembly 2 and the string of downhole tubulars 4 being engaged or withdrawn to and from the wellbore. Embodiments disclosed herein enable the fluid connection between the top-drive 2 (in communication with a mud pump 23 and the string of downhole tubulars 4 to be made using a hydraulic connector tool 10 located between top-drive assembly 2 and the top joint of string of downhole tubulars 4.

[0031] However, it should be understood that while a top-drive assembly 2 is shown in conjunction with hydraulic connector 10, in certain embodiments, other types of "lifting assemblies" may be used with hydraulic connector 10 instead. For example, when "running" casing or drill pipe {i.e., downhole tubulars 4) on drilling rigs {e.g., 12) not equipped with a top-drive assembly 2, hydraulic connector 10, elevator 8, and lifting bales 6 may be connected directly to a hook or other lifting mechanism to raise and/or lower the string of downhole tubulars 4 while hydraulically connected to a pressurized fluid source {e.g., a mud pump, a rotating swivel, an IBOP, a TIW valve, an upper length of tubular, etc.). Further still, while some drilling rigs may be equipped with a top-drive assembly 2, the lifting capacity of the lifting ears (or other components) of the top-drive 2 may be insufficient to lift the entire length of string of downhole tubular 4. In particular, for extremely long or heavy-walled tubulars 4, the hook and lifting block of the drilling rig may offer significantly more lifting capacity than the top-drive assembly 4.

[0032] Therefore, throughout the present disclosure, where connections between hydraulic connector 10 and top-drive assembly 2 are described, various alternative connections between the hydraulic connector and other, non-top-drive lifting (and fluid communication) components are contemplated as well. Similarly, throughout the present disclosure, where fluid connections between hydraulic connector 10 and top- drive assembly 2 are described, various fluid and/or lifting arrangements are contemplated as well. In particular, while fluids may not physically flow through a particular lifting assembly lifting hydraulic connector 10 and into tubular, fluids may flow through a conduit (e.g., hose, flex-line, pipe, etc) used alongside and in conjunction with the lifting assembly and into hydraulic connector 10.

[0033] With reference to Figure 2, a hydraulic connector 10, according to a first embodiment of the disclosure, comprises a cylinder 15 and a piston-rod assembly 20, the piston-rod assembly 20 being slidably engaged in the cylinder 15. The piston-rod assembly 20 may further comprise a hollow tubular rod 30, on which is mounted a cap 40, the tubular rod 30 being slidably engaged in the cylinder 15 such that a first end (i.e., a lower end) of the tubular rod 30 protrudes outside the cylinder 15 and a second end (i.e., an upper end) is within the cylinder 15. The cap 40 is shown mounted on the second, upper, end of the tubular rod 30, whilst on a first end of the tubular rod 30 there is located a bung 60 with seals (e.g., cup seals) 130. The bung 60 may be made from an appropriate sealing material, including, but not limited to, nylon, rubber, or any other appropriate polymer or elastomer, and may be shaped to fit into the top end (typically a box end) of the string of downhole tubulars 4.

[0034] A tubular filter 200 may be disposed between the first end of the tubular rod 30 and the bung 60. The filter 200 may be substantially cylindrical with a closed end and an open end between its side-walls. The open end of the filter 200 may comprise an outer- flanged portion about its circumference, which may abut the first end of the tubular rod 30. As shown, the bung 60 threadably engages an outer portion of the first end of the tubular rod 30 and an abutment shoulder within bung 60 abuts the flanged portion of the filter 200 to secure it between the tubular rod 30 and bung 60. In this manner the bung 60 and filter 200 may easily be disconnected from the lower end of tubular rod 30 for replacement, inspection, and/or cleaning.

[0035] As shown, filter 200 is arranged with its open end facing (downward) toward bung 60 and the closed end (upward) facing cap 40. Thus, filter 200 may be contained primarily within tubular rod 30 so that flow from the string of downhole tubulars 4 to the hydraulic connector 10 flows will first enter the open end of filter 200, then encounter the side-walls, and finally the closed end of the filter 200. The filter 200 may be sized so that a sufficient gap is provided between the side-walls of the filter and the tubular rod 30, whilst maintaining a sufficient internal diameter of the filter. The dimensions of the filter 200 (e.g., diameter, length, etc.) relative to the tubular rod 30 may be selected so as to reduce the pressure drop across the filter. In certain embodiments, filter 200 may comprise a perforated pipe having a perforated closed end. In alternative embodiments filter 200 may comprise a wire mesh. In still further alternative embodiments, filter 200 may comprise a non-perforated closed end. or any other conventional filter arrangement known to those having ordinary skill.

[0036] The tubular rod 30, cylinder 15, bung 60 and cap 40 shown in Figure 2 are arranged such that their longitudinal axes are coincident. At the lower end of the cylinder 15, beyond which the tubular rod 30 protrudes, there is mounted an end-cap 42. The end- cap 42 seals the inside of the cylinder 15 from the outside, whilst also allowing the tubular rod 30 to slide (i.e., reciprocate) in or out of the cylinder 15. Seals 25 (e.g., o- rings) may be used to seal between the end-cap 42 and tubular rod 30.

[0037] As shown in Figure 2, hydraulic connector 10 further includes a piston 50 slidably mounted on tubular rod 30 inside cylinder 15. As shown, piston 50 is free to reciprocate between the cap 40 and the end-cap 42. Additionally, in certain embodiments, piston 50 may also be capable of rotating about its center axis with respect to cylinder 15. Furthermore, the entire assembly (20, 40, 50 and 60) may be able to slide (and/or rotate) with respect to cylinder 15. As such, the inside of the cylinder 15 may be divided by the piston 50 into a first (lower) chamber 80 and a second (upper) chamber 70. When viewed in a downward direction from above (e.g., from the top-drive), the projected area of the piston 50 may be less than the projected area of the cap 40 such that when the piston 50 abuts the cap 40, the pressure force from the fluid in the second chamber 70 acting on the cap 40 is greater than that acting on the piston 50.

[0038] In certain embodiments, the first and second chambers 80 and 70 may be energized with air and drilling mud respectively. Alternatively, any appropriate actuation fluid, including, but not limited to, air, nitrogen, water, drilling mud, and hydraulic fluid, may be used to energize lower chamber 80. The piston 50 may be sealed against the tubular rod 30 and cylinder 15, for example, by means of o-ring seals 52 and 54, to prevent fluid communication between the two chambers 70 and 80. First chamber 80 may be in fluid communication with an air supply via a port 100, which may selectively pressurize first chamber 80. Second chamber 70 may be provided with drilling mud from the top-drive 2 via a socket 90, which may (as shown) be a box component of a rotary box-pin threaded connection. Top-drive 2 may be connected to the hydraulic connector 10 via the engagement of a cooperating (e.g., a pin component of a rotary box-pin) threaded connection (not shown).

[0039] As shown in Figure 2, the piston 50 and cap 40 are touching, so that drilling mud cannot flow from the second chamber 70 to the string of downhole tubulars 4. Figure 3 shows an alternative position of the cap 40 with respect to piston 50. As shown in Figure 3, with the cap 40 and piston 50 apart, holes 120 are exposed in the side of the cap 40. These holes 120 provide a fluid communication path between the second chamber 70 and the interior of the tubular rod 30. Thus drilling mud may flow from the second chamber 70 to the string of downhole tubulars 4, via the holes 120 in the cap 40 and the tubular rod 30 when cap 40 is displaced above piston 50. (0040] With reference to Figure 4a, the bung 60, may comprise a detachable shaft 105.

Detachable shaft 105 may be threadably attached to tubular rod 30 and may therefore be selectively detachable from tubular rod 30. Additionally, seals 130 may be provided around an outer profile of detachable shaft 105. Detachable shaft 105 may be hollow to accommodate fluids flowing from top-drive assembly 2, through shaft 16, through tubular rod 30, and into downhole tubular 4.

[0041] In certain embodiments, detachable shaft 105 and attached seals 130 may be interchangeable with alternative shaft and seal configurations. In select embodiments, interchangeable configurations may facilitate repair and replacement of worn seals 130. Further, interchangeable configurations may allow for bungs 60 of different shapes and configurations to be deployed for different configurations of downhole tubulars (e.g., 4 of Figure 1). Furthermore, in certain embodiments, a connection between tubular rod 30 and detachable shaft 105 may be constructed to act as a sacrificial connection. In such embodiments, if an impact load is applied to bung 60, the connection may fail, so that piston-rod assembly 20, cylinder 15, and remainder of hydraulic connector 10 may be protected from damage. For example, detachable shaft 105 may be provided with a female-threaded socket configured to engage a corresponding male thread of tubular rod 30. As such, the female thread of detachable shaft 105 may be deliberately weakened, for example, at its root, so that it may fail before damage occurs to tubular rod 30. Filter 200 may be located between an abutment shoulder in the female threaded socket of the detachable shaft 105 and the male thread on the tubular rod 30.

[0042] In select embodiments, the end of the detachable shaft 105 attached to tubular rod

30, may have similar (or smaller) external dimensions as tubular rod 30 to ensure that detachable shaft 105 may fit inside a threaded member 1 10 that (in certain embodiments) may optionally be threaded to the end of end-cap 42. Threaded member 1 10 may be connected to the first end cap 42 by virtue of a threaded connection and the threaded member 1 10 is hollow to allow the tubular rod 30 to pass through it. The threaded member 1 10 may seal the inside of cylinder 15 from the outside, whilst also allowing the tubular rod 30 to slide in or out of the cylinder 15. In another alternative embodiment, the threaded member 1 10 and end-cap 42 may be integral and comprise a single component.

[0043] The end of the detachable shaft 105, which attaches to the tubular rod 30, has the same or smaller external dimensions as the tubular rod 30. This ensures that the detachable shaft 105 fits inside the threaded member 1 10. Furthermore, the detachable shaft 105 has a protrusion 106, which acts as a mechanical stop limiting the retraction of the piston-rod assembly 20 into the cylinder 15. The protrusion 106 is shaped with spanner flats so that the detachable shaft 105 can be removed from the tubular rod 30.

[0044] Referring now to Figure 4b, tubular rod 30 is shown further including an abutment shoulder 150. In certain embodiments, abutment shoulder 150 may be formed as a flat portion on the outer surface of tubular rod 30 adjacent to a cylindrical portion. Abutment shoulder 150 may provide a keyway configured to receive a corresponding key 160 of threaded member 110. Key 160 may engage the keyway of abutment shoulder 150 so that rotation of the tubular rod 30 relative to threaded member 110 is prevented, thereby facilitating removal of detachable shaft 105. Furthermore, tubular rod 30 may be fully retracted within threaded member 1 10 when detachable shaft 105 is removed, such that tubular rod 30 does not extend beyond the end of threaded member 110. Key 160 and keyway may also mechanically limit the retraction of the piston-rod assembly 20 when detachable shaft 105 is removed.

[0045] Additionally, threaded member 1 10 may optionally include a threaded section

170. In select embodiments, threaded section 170 may threadably connect to an open end of downhole tubular 4 so that hydraulic connector 10 may transmit torque from top- drive assembly 2 to downhole tubular 4. Accordingly, in order to transmit torque, threaded connections between top-drive assembly 2, threaded connection 25, threaded member 1 10, and downhole tubular 4 should be selected that the make-up and break-out directions are the same.

[0046| One or more intermediate portions may be fitted to the threaded section 170 so that the threaded member 1 10 (and hence connector 10) may be connected to a variety of tubulars having different diameters. For example, an intermediate portion in the form of a swage may be connected to both (a) the threaded section 170 of the threaded member by virtue of an internal thread in the swage (i.e. a box connection) and (b) the internal thread of a casing string section by virtue of an external thread on the swage body (i.e. pin connection). Thus, by providing a plurality of intermediate portions with a range of external dimensions, the connector 10 may be connected to a corresponding range of downhole tubulars.

[0047] Detachable shaft 105 (and therefore bung 60) may be removed from the tubular rod 30 when threaded member 1 10 is connected (directly) to downhole tubular 4. Tubular rod 30 may be sized so that it fits inside the interior of downhole tubular 4 beyond a threaded portion of an open end of downhole tubular 4. Alternatively, tubular rod 30 may be retracted into threaded member 1 10.

[0048] In an alternative embodiment, detachable shaft 105 need not be removed from tubular rod 30 when threaded member 110 is attached directly to downhole tubular 4. Hydraulic connector 10 may be connected to downhole tubular 4 by both bung 60 and threaded member 110. As such, the alternative embodiment may allow rapid connection of hydraulic connector 10 between a downhole tubular 4 and a top-drive assembly 2 without having to remove the detachable shaft 105, thereby saving time and money. To engage threaded member 110 with downhole tubular 4 without removing detachable shaft 105, protrusion 106 may be constructed smaller than shown in Figure 3a so that it does not radially extend beyond the outer surface of bung 60.

[0049] Additionally, threaded member 110 may be removable from first end cap 42 and may therefore be interchangeable with alternative threaded members. This interchangeability may facilitate repair of the threaded member 1 10 and may also enable differently-shaped threaded members (110) to be configured for use with a particular downhole tubular 4.

[0050] Figures 5 and 6 are representations of the bung 60 and the threaded member 1 10 respectively showing the features mentioned above in perspective view.

[0051] Additionally, referring to Figures 7a and 7b, threaded section 170 of threaded member 1 10 may include a "protector" cap 180 may be provided to protect threads 170 when not in use. Such a protector cap 180 may be constructed of any metallic material known those having ordinary skill in oilfield connections, but may, in the alternative, be constructed from plastic or elastomeric materials (e.g., urethane, nylon, PTFE, polyethylene, etc.). Additionally, protector cap 180 may be constructed as a generally tubular member having internal threads 190 corresponding to threads 170 at a proximal end and an open end (through which components of piston-rod assembly 20, bung 60, or tubular rod 30 may pass) at a distal end. Optionally, the protector cap may include an elongated tubular portion between the distal and proximal ends to server as a protector for components of piston-rod assembly 20 that may be retracted or otherwise housed within the threaded protector cap 180.

[0052] With reference to Figures 8a and 8b, a hydraulic connector 10, according to an alternative embodiment of the disclosure, is shown comprising a poppet valve 210. The poppet valve 210 is a one-way flow valve and may be used in place of the valve shown in Figures 2 and 3. The hydraulic connector 10, according to this alternative embodiment may also comprise an additional cup seal 260 on bung 60 to facilitates improved engagement with the top end of the string of downhole tubulars 4. However, those having ordinary skill in the art will appreciate that cup seals should not be limited to the embodiment shown in Figures 8a and 8b, in that cup seals may be applicable to the embodiments shown in Figures 2-5 as well.

[0053] Additionally, filter 200 of this alternative embodiment may also comprise a conical section at the closed end of the filter 200 facing the cap 40. The conical section on the filter 200 may assist in directing the flow from the hydraulic connector 10 to the string of downhole tubulars 4 and may also improve the ability of the filter 200 to self- clean.

[0054] With reference to Figures 9a and 9b, the threaded member 1 10 in accordance with embodiments disclosed herein may include one or more teeth 270 and the tubular rod 30 (or tubular-rod assembly 20) may one or more corresponding teeth 280. Teeth 270 of threaded member 1 10 may be provided on an end face of the threaded member 1 10 and teeth 280 may be provided on a ring disposed about tubular rod 30. Teeth 270 of threaded member 110 and teeth 280 of tubular rod 30 may be arranged so that when tubular rod 30 is in a retracted position (Figure 9b), teeth 270 interlock with teeth 280 and relative rotation between the body portion of hydraulic connector 10 and tubular rod 30 is prevented. In contrast, when the tubular rod 30 is in an extended position (Figure 9a), teeth 270 and 280 are disengaged and tubular rod 30 is free to rotate relative to the body portion (i.e., threaded member 1 10) of hydraulic connector 10. Alternatively, teeth 270 may be provided on the body portion of hydraulic connector 10 rather than upon threaded member 110. Additionally, teeth 270 and 280 may be constructed as splines and corresponding recesses.

[0055] Operation of the hydraulic connector 10 according to the embodiments disclosed herein will now be described. To extend the piston rod 30, so that the bung 60 and seal 130 engage the string of downhole tubulars 4, the pressure of the drilling mud in the second chamber 70 of the connector may be increased by allowing flow from the top- drive 2. The air in the first chamber 80 may be set at a pressure sufficiently high to ensure that the piston 50 abuts the cap 40. As the pressure of the drilling mud increases, the force exerted by the drilling mud on the piston 50 and cap 40 exceeds the force exerted by the air in the first chamber on the piston 50 and the air outside the hydraulic connector 10 acting on the piston-rod assembly 20. The cap 40 is then forced toward the end-cap 42 and the piston-rod assembly 20 extends. As the projected area of the cap 40 is greater than the projected area of the piston 50 and the air pressure in the first chamber 80 is only exposed to the piston 50, the piston 50 may remain abutted against cap 40. Thus, whilst the piston-rod assembly 20 is extending, the holes 120 are not exposed and drilling mud cannot flow from the top-drive 2 into the string of downhole tubulars 4.

[0056] Once the bung 60 and seals 130 are forced into the open threaded end of the upper end of the string of downhole tubulars 4, thereby forming a fluid tight seal between the piston-rod assembly 20 and the open end of the drill string 4, the piston-rod assembly 20, and hence cap 40, are no longer able to extend. In contrast, as the piston 50 is free to move on the tubular rod 30, the piston 50 is forced further along by the pressure of the drilling mud in the second chamber 70. The holes 120 are thus exposed and drilling mud is allowed to flow from the second chamber 70, through the piston-rod assembly 20 and into the string of downhole tubulars 4. With the holes 120 open, the hydraulic connector 10 will ensure that the volume displaced by the removal of the string of downhole tubulars 4 from the well is replaced by drilling mud. The pressure of the air in the first chamber 80 may then be released until retraction of the piston-rod assembly 20 is required.

[0057] If the piston-rod assembly 20 extends fully from cylinder 15 before bung 60 and seals 130 fully engage string of downhole tubulars 4, the piston 50 will be prevented from lowering further by the end-cap 42. The holes 120 will therefore be unable to open and this ensures that no drilling mud is spilt if the piston-rod assembly 20 does not fully engage a string of downhole tubulars 4.

[0058] Finally, when it is desired to retract the piston-rod assembly 20 from the string of downhole tubulars 4, the pressure of the air in the first chamber 80 may be increased. The top-drive's drilling mud pumps may also be stopped to reduce the pressure of the drilling mud in the second chamber 70. The force exerted on the piston 50 by the drilling mud may then be less than the force exerted on the piston 50 by the air so that the piston 50 is biased towards the cap 40 and socket 90. The upward movement of piston 50 retracts the piston-rod assembly 20 into the cylinder 15 and out of string of downhole tubulars 4. Additionally, the upward movement of piston 50 results in abutment of the cap 40 therewith, thereby closing the holes 120 and preventing mud from flowing out of the hydraulic connector 10. With the piston-rod assembly 20 is retracted, the bung 60 and the seals 130 are retracted from the string of downhole tubulars 4 and the top most section of the string of downhole tubulars 4 may be removed.

[0059] During back-flow, when drilling fluid flows from the string of downhole tubulars

4 to the top-drive 2, the filter 200 may filter out any debris and particulate matter, thereby protecting various components of the hydraulic connector 10 and the top-drive 2. The (upward) orientation of the filter 200 encourages any debris to collect at the closed (i.e., uppermost) end of the filter. Thus, when the flow is reversed such that drilling fluid flows from the top-drive 2 to the string of downhole tubulars 4, the debris that has collected at the closed end of the filter is flushed back into the well-bore. The filter 200 may therefore exhibit a self-cleaning function as a result of its orientation. By contrast, if the filter 200 were orientated with the closed end facing the string of downhole tubulars 4, debris would collect about the flange of the filter during back-flow. Reversal of the flow (i.e., toward the string of downhole tubulars 4) would then not be as effective at removing the debris from around the flange. The accumulation of debris may result in an increase in the pressure drop across the filter.

[0060] As described above, the hydraulic connector 10 may replace the traditional threaded connection between a top-drive 2 and string of downhole tubulars 4 during the removal or lowering of a string of downhole tubulars 4 from or into a well. Advantageously, the hydraulic connector permits a hydraulic connection between the top- drive 2 and the string of downhole tubulars 4 during tripping operations. As such, the hydraulic connector 10 may be used to more rapidly sealingly engage and disengage the string of downhole tubulars 4 without risk of damaging the threaded portions of either the top-drive 2 or the string of downhole tubulars 4.

[0061] Furthermore, the above-mentioned features provide a more versatile connector.

Advantageously, the hydraulic connector may remain connected to the top-drive 2 when a direct (i.e., a torque transmitting) connection to the sting of downhole tubulars 4 is needed to turn the tubular 4. Rather than remove the entire hydraulic connector 10, the detachable shaft 105 may be quickly removed from the tubular rod 30 and the hydraulic connector 10 may engage directly with the drill string 4 by virtue of a threaded section 170 of threaded member 1 10 (Figure 4b). By not having to disassemble and disengage hydraulic connector 10, time, and therefore rig costs, may be saved.

[0062] Advantageously, a hydraulic connector may provide a fluid tight connection between a fluid supply and a downhole tubular, including a body portion and an extendable portion, the extendable portion having a seal at or towards its free end which is adapted to selectively sealingly engage the downhole tubular; and a threaded portion provided on the body portion; the threaded portion being adapted to selectively engage with a threaded section of the downhole tubular; wherein the extendable portion extends through the threaded portion. The extendable portion may engage the downhole tubular when the extendable portion is at least partially extended from the body portion. The body portion may be a cylinder and the extendable portion may be a piston-rod. The connector may selectively connect to the downhole tubular via the threaded portion engaging with a corresponding threaded section inside the open end of the downhole tubular.

[0063] The seal may comprise a tapered bung adapted to be located in the open end of the downhole tubular. The seal may be detachable from the extendable portion. The extendable portion may be retractable within the threaded portion, so that the extendable portion may not be exposed beyond the end of the threaded portion. The extendable portion may be adapted to fit inside the interior of the downhole tubular beyond the threaded section in the open end of the downhole tubular. The extendable portion may be provided with a mechanical stop limiting the retraction of the extendable portion into the body portion. The extendable portion may be hollow and may provide a flow communication path between the fluid supply and the downhole tubular.

[0064] The threaded portion may be provided on a threaded member disposed about the extendable portion, and the threaded member may be detachable from the body portion. The threaded member may be threadably engaged with the body portion. The threaded member may be interchangeable with one or more alternative threaded members. The extendable portion may be provided with a formation such as a keyway and at least one of the body portion and the threaded member may be provided with a cooperating formation such as a corresponding keyway and/or a key. The key may interface with the keyway of the extendable portion so that rotation of the extendable portion with respect to the body portion may be prevented. The key and keyway may also provide a mechanical stop limiting the retraction of the extendable portion.

[0065] The extendable portion may be provided with splines and at least one of the body portion and the threaded member may be provided with corresponding splines. The splines on the extendable portion may engage with the corresponding splines, so that rotation of the extendable portion with respect to the body portion may be prevented. The splines may be straight and may be parallel to a longitudinal axis of the body portion. The splines may only be formed on a distal end of the extendable portion and/or on a distal end of the body portion.

[0066] The connector may be capable of transmitting torque from a top-drive to the downhole tubular via the threaded portion engaging with the threaded section of the downhole tubular. 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 tubular may comprise a standard box connection. The extendable portion may comprise a filter. The downhole tubular may be a drill-string, a casing string or any other tubular for sending downhole.

[0067] Advantageously, a hydraulic connector may provide a fluid tight connection between a fluid supply and a downhole tubular including a body portion and an extendable portion, the extendable portion having a seal at or towards its free end which is adapted to selectively sealingly engage the downhole tubular; and wherein the seal is detachable from the extendable portion. The seal may be provided on a shaft and the shaft may be detachable from the extendable portion. The shaft may be threadably engaged with the extendable portion, for example with a stub-acme connection.

[0068] A connection between the extendable portion and the shaft may act as a sacrificial connection such that if an impact load is applied to the shaft, the extendable portion and body portion may be protected. The connection between the piston-rod and the shaft may be box weak. The shaft may be hollow. The seal may be interchangeable with one or more alternative seals. The connector may further comprise a threaded portion provided on the body portion and the threaded portion may be adapted to engage with a threaded section of the downhole tubular; wherein the extendable portion extends through the threaded portion.

[0069] Advantageously, a hydraulic connector may provide a fluid tight connection between a fluid supply and a downhole tubular, the connector comprising a body portion and an extendable portion, the extendable portion having a seal at or towards its free end which is adapted to sealingly engage the downhole tubular, wherein the extendable portion comprises a filter. The filter may be provided in the extendable portion. The seal may be detachable from the extendable portion and the seal may be provided on a shaft, the shaft being detachable from the extendable portion. The filter may comprise a flange which may be located between the detachable shaft and the extendable portion such that the filter may also be detachable from the shaft.

[0070] The filter may be substantially tubular, with a closed end and an open end. The open end of the tubular filter may be closest to the downhole tubular and the closed end of the tubular filter may be furthest from the downhole tubular. The closed end may be conical in shape. The filter may comprise a wire mesh. The filter may comprise a perforated tube. The filter may be self cleaning.

[0071] Advantageously, a kit of parts may include a connector, which provides a fluid tight connection between a fluid supply and a downhole tubular, the connector having an extendable portion and a body portion, the extendable portion being adapted to receive a seal at or towards its free end which is adapted to selectively sealingly engage the downhole tubular, and at least two removable and interchangeable seals of different dimensions.

[0072] A threaded portion may be provided on the body portion, and the threaded portion may be adapted to selectively engage with a threaded section in an open end of the downhole tubular. The threaded portion may be removable and interchangeable and the kit may further comprise at least two removable and interchangeable threaded portions of different dimensions.

[0073] Advantageously, a kit of parts may include a connector, which provides a fluid tight connection between a fluid supply and a downhole tubular, the connector having an extendable portion and a body portion, the body portion being adapted to receive a threaded portion, the threaded portion being adapted to selectively engage with a threaded section in an open end of the downhole tubular, and at least two removable and interchangeable threaded portions of different dimensions.

[0074] The extendable portion may be adapted to receive a seal at or towards its free end which is adapted to selectively sealingly engage the downhole tubular. The extendable portion may be removable and interchangeable and the kit may further comprise at least two removable and interchangeable seals of different dimensions. The threaded portions may have a different shape and/or size and/or thread. The extendable portion may extend through the threaded portion. The seals may have a different shape and/or size.

[0075J Advantageously, a method to provide a fluid tight connection between a fluid supply and a downhole tubular using a connection including an extendable portion and a body portion, the extendable portion having a seal at or towards its free end which is adapted to selectively sealingly engage the downhole tubular, and a threaded portion provided on the body portion, the threaded portion being adapted to selectively engage with a threaded section of the downhole tubular, may include engaging at least one of the seal and the threaded member with the downhole tubular.

[0076] The method may comprise exchanging the seal for a second seal. The method may comprise exchanging the threaded member for a second threaded member. The method may comprise swapping the engagement of the threaded member with the downhole tubular to an engagement of the seal with the downhole tubular. The method may comprise swapping the engagement of the seal with the downhole tubular to an engagement of the threaded member with the downhole tubular.

[0077] The method may comprise rotating the downhole tubular. The method may comprise the additional step of applying drilling fluid to the downhole tubular.

[0078] The extendable portion may extend through the threaded portion and at least one of the seal and the threaded member may be engaged in the open end of the downhole tubular. The connector may comprise a hydraulic ram, the body portion comprising the cylinder of the ram and the extendable portion comprising the piston of the ram.

[0079] To avoid unnecessary duplication of effort and repetition in the text, certain features are described in relation to only one or several aspects or embodiments of the disclosure. However, it is to be understood that, where it is technically possible, features described in relation to any aspect or embodiment of the disclosure may also be used with any other aspect or embodiment of the disclosure. [0080] Furthermore, the mixing and matching of features, elements and/or functions between various embodiments is expressly contemplated herein so that one of ordinary skill in the art would appreciate from this disclosure that features, elements and/or functions of one embodiment may be incorporated into another embodiment as appropriate, unless described otherwise above. Moreover, many modifications may be made to adapt a particular situation or material to the teachings of the disclosure without departing from the essential scope thereof.

[0081] Therefore, while the disclosure has been presented with respect to a limited number of embodiments, those skilled in the art, having benefit of this disclosure, will appreciate that other embodiments may be devised which do not depart from the scope of the present disclosure. Accordingly, the scope of the disclosure should be limited only by the attached claims.

Claims

CLAIMS What Is Claimed Is:

1. A hydraulic connector to provide a fluid tight connection between a fluid supply and a downhole tubular, the connector comprising: an engagement assembly configured to extend and retract a seal assembly disposed at a distal end of the hydraulic connector into and from a proximal end of the downhole tubular; and a valve assembly operable between an open position and a closed position; wherein the valve assembly is configured to allow the fluids to communicate between the fluid supply and the downhole tubular through the seal assembly when in the open position, and wherein the valve assembly is configured to prevent fluid communication between the fluid supply and the downhole tubular when closed position.

2. The hydraulic connector of claim 1, further comprising: a threaded portion provided on a body of the hydraulic connector, the threaded portion configured to threadably engage a threaded section of the downhole tubular; wherein an extendable portion of the seal assembly extends through the threaded portion.

3. The hydraulic connector of claim 2, wherein the threaded portion threadably engages the downhole tubular inside a box threaded end of the downhole tubular.

4. The hydraulic connector of claim 2 or 3, wherein at least one seal of the seal assembly is detachable from the extendable portion.

5. The hydraulic connector of claim 4, wherein the extendable portion is retractable within the threaded portion, so that the extendable portion is not exposed beyond the end of the threaded portion.

6. The hydraulic connector of claim 4 or 5, wherein the extendable portion fits inside the interior of the downhole tubular beyond the threaded section in the proximal end of the downhole tubular.

7. The hydraulic connector of any one of claims 2 to 6, wherein the extendable portion comprises a mechanical stop to limit the retraction of the extendable portion into the hydraulic connector.

8. The hydraulic connector of any one of claims 2 to 7, wherein the extendable portion comprises a through bore to provide a flow communication path between the fluid supply and the downhole tubular.

9. The hydraulic connector of any one of claims 2 to 8, wherein the threaded portion is provided on a threaded member disposed about the extendable portion, the threaded member being detachable from the hydraulic connector.

10. The hydraulic connector of claim 9, wherein the threaded member is threadably engaged with a body portion of the hydraulic connector.

11. The hydraulic connector of claim 9 or 10, wherein the threaded member is interchangeable with one or more alternative threaded members.

12. The hydraulic connector of any one of claims 9 to 11, wherein the extendable portion comprises a keyway configured to receive a key and to prevent rotation of the extendable portion with respect to remainder of the hydraulic connector.

13. The hydraulic connector of any one of claims 2 to 12, wherein the hydraulic connector is configured to transmit torque from a top-drive to the downhole tubular via the threaded portion engaging with the threaded section of the downhole tubular.

14. The hydraulic connector of any one of claims 2 to 13, wherein the extendable portion comprises a filter.

15. The hydraulic connector of any one of claims 1 to 14, wherein the seal assembly comprises a tapered bung configured to seal inside the proximal end of the downhole tubular.

16. A hydraulic connector to provide a fluid tight connection between a fluid supply and a downhole tubular, the connector comprising: a body portion; an extendable portion recriprocable with respect to the body portion; and a seal assembly at a distal end of the extendable portion; wherein the seal assembly is configured to sealingly engage the downhole tubular, and wherein the seal assembly is detachable from the extendable portion.

17. The hydraulic connector of claim 16, wherein the seal assembly comprises a seal on a shaft, the shaft being detachable from the extendable portion.

18. The hydraulic connector of claim 17, wherein the shaft is threadably engaged with the extendable portion.

19. The hydraulic connector of claim 17 or 18, further comprising a sacrificial connection between the extendable portion and the shaft to protect the extendable portion and the body portion in the event of an impact load.

20. The hydraulic connector of any one of claims 17 to 19, wherein the shaft comprises a through bore.

21. The hydraulic connector of any one of claims 16 to 20, wherein the seal assembly is interchangeable with one or more alternative seal assemblies.

22. The hydraulic connector of any one of claims 16 to 21, wherein the connector further comprises a threaded portion provided on the body portion; the threaded portion being adapted to engage with a threaded section of the downhole tubular; wherein the extendable portion extends through the threaded portion.

23. The hydraulic connector of any one of claims 16 to 22, further comprising: locking teeth of the body portion; and corresponding teeth of the extendable portion; wherein the locking teeth and the corresponding teeth are configured to restrict rotation of the extendable portion when the extendable portion is in a retracted position with respect to the body portion.

24. The hydraulic connector of any one of claims 16 to 23, wherein the extendable portion further comprises a filter.

25. The hydraulic connector of claim 24, wherein the filter comprises a flange located between a detachable shaft and the extendable portion.

26. The hydraulic connector of claim 24 or 25, wherein the filter is substantially tubular and comprises a closed end and an open end.

27. The hydraulic connector of any one of claims 16 to 26, wherein the seal assembly comprises at least two removable and interchangeable seals of different dimensions.

28. A method to provide a fluid tight connection between a fluid supply and a downhole tubular using a hydraulic connector, the method comprising: disposing a seal assembly upon a distal end of a piston-rod assembly; increasing a pressure of fluids in the fluid supply; extending the piston-rod assembly; engaging the seal assembly within a proximal end of the downhole tubular; and engaging at least one of the seal assembly and a threaded member within a proximal end of the downhole tubular.

29. The method of claim 28, further comprising hydraulically communicating fluids between the fluid supply and the downhole tubular.

30. The method of claim 28 or 29, further comprising transmitting torque between the fluid supply and the downhole tubular.

31. The method of any one of claims 28 to 30, wherein the fluid supply comprises at least one of a top-drive assembly, a rotating swivel, and downhole tubular.

32. The method of any one of claims 28 to 31, further comprising exchanging the threaded member for a second threaded member.

33. The method of any one of claims 28 to 32, further comprising restricting rotation of the piston-rod assembly with respect to a body of the hydraulic connector when the piston-rod assembly is in a retracted position.

34. A connector which provides a fluid tight connection between a fluid supply and a downhole tubular, the connector comprising: a body portion and an extendable portion, the extendable portion having a seal at or towards its free end which is adapted to selectively sealingly engage the downhole tubular; and a threaded portion provided on the body portion; the threaded portion being adapted to selectively engage with a threaded section of the downhole tubular; wherein the extendable portion extends through the threaded portion.

35. The connector as claimed in claim 34, wherein the connector selectively connects to the downhole tubular via the threaded portion engaging with a corresponding threaded section inside the open end of the downhole tubular.

36. The connector as claimed in claim 34 or 35, wherein the seal comprises a tapered bung adapted to be located in the open end of the downhole tubular.

37. The connector as claimed in any one of claims 34 to 36, wherein the seal is detachable from the extendable portion.

38. The connector as claimed in claim 37, wherein the extendable portion is retractable within the threaded portion, so that the extendable portion is not exposed beyond the end of the threaded portion.

39. The connector as claimed in claim 37 or 38, wherein the extendable portion fits inside the interior of the downhole tubular beyond the threaded section in the open end of the downhole tubular.

40. The connector as claimed in any one of claims 34 to 39, wherein the extendable portion is provided with a mechanical stop limiting the retraction of the extendable portion into the body portion.

41. The connector as claimed in any one of claims 34 to 40, wherein the extendable portion is hollow and provides a flow communication path between the fluid supply and the downhole tubular.

42. The connector as claimed in any one of claims 34 to 41 , wherein the threaded portion is provided on a threaded member disposed about the extendable portion, the threaded member being detachable from the body portion.

43. The connector as claimed in claim 42, wherein the threaded member is threadably engaged with the body portion.

44. The connector as claimed in claim 42 or 43, wherein the threaded member is interchangeable with one or more alternative threaded members.

45. The connector as claimed in any one of claims 42 to 44, wherein the extendable portion is provided with a keyway and at least one of the body portion and the threaded member is provided with a key, the key interfacing with the keyway of the extendable portion so that rotation of the extendable portion with respect to the body portion is prevented.

46. The connector as claimed in claim 45, wherein the key and keyway provide a mechanical stop limiting the retraction of the extendable portion.

47. The connector as claimed in any one of claims 34 to 46, wherein the connector is capable of transmitting torque from a top-drive to the downhole tubular via the threaded portion engaging with the threaded section of the downhole tubular.

48. The connector as claimed in any one of claims 34 to 47, wherein the extendable portion comprises a filter.

49. A connector which provides a fluid tight connection between a fluid supply and a downhole tubular, the connector comprising: a body portion and an extendable portion, the extendable portion having a seal at or towards its free end which is adapted to selectively sealingly engage the downhole tubular; and wherein the seal is detachable from the extendable portion.

50. The connector as claimed in claim 49, wherein the seal is provided on a shaft, the shaft being detachable from the extendable portion.

51. The connector as claimed in claim 50, wherein the shaft is threadably engaged with the extendable portion.

52. The connector as claimed in claim 50 or 51 , wherein a connection between the extendable portion and the shaft acts as a sacrificial connection such that if an impact load is applied to the shaft, the extendable portion and body portion are protected.

53. The connector as claimed in any one of claims 50 to 52, wherein the shaft is hollow.

54. The connector as claimed in any one of claims 49 to 53, wherein the seal is interchangeable with one or more alternative seals.

55. The connector as claimed in any one of claims 49 to 54, wherein the connector further comprises a threaded portion provided on the body portion; the threaded portion being adapted to engage with a threaded section of the downhole tubular; wherein the extendable portion extends through the threaded portion.

56. A connector which provides a fluid tight connection between a fluid supply and a downhole tubular, the connector comprising a body portion and an extendable portion, the extendable portion having a seal at or towards its free end which is adapted to sealingly engage the downhole tubular, wherein the extendable portion comprises a filter.

57. The connector as claimed in claim 56, wherein the filter is provided in the extendable portion.

58. The connector as claimed in claim 56 or 57, wherein the seal is detachable from the extendable portion and the seal is provided on a shaft, the shaft being detachable from the extendable portion.

59. The connector as claimed in claim 58, wherein the filter comprises a flange which is located between the detachable shaft and the extendable portion such that the filter is also detachable from the shaft.

60. The connector as claimed in any one of claims 56 to 59, wherein the filter is substantially tubular, with a closed end and an open end.

61. The connector as claimed in claim 60, wherein the open end of the tubular filter is closest to the downhole tubular and the closed end of the tubular filter is furthest from the downhole tubular.

62. The connector as claimed in claim 60 or 61, wherein the closed end is conical in shape.

63. The connector as claimed in any one of claims 56 to 62, wherein the filter comprises a wire mesh.

64. The connector as claimed in any one of claims 56 to 63, wherein the filter comprises a perforated tube.

65. The connector as claimed in any one of claims 56 to 64, wherein the filter is self cleaning.

66. The connector as claimed in any one of claims 34 to 65, wherein the fluid supply comprises a top-drive assembly.

67. A kit of parts comprising: a connector, which provides a fluid tight connection between a fluid supply and a downhole tubular, the connector having an extendable portion and a body portion, the extendable portion being adapted to receive a seal at or towards its free end which is adapted to selectively sealingly engage the downhole tubular; and at least two removable and interchangeable seals of different dimensions.

68. The kit of parts for the connector as claimed in claim 67, wherein the body portion is adapted to receive a threaded portion, the threaded portion being adapted to selectively engage with a threaded section in an open end of the downhole tubular; and the kit further comprises at least two removable and interchangeable threaded portions of different dimensions.

69. A kit of parts comprising: a connector, which provides a fluid tight connection between a fluid supply and a downhole tubular, the connector having an extendable portion and a body portion; the body portion being adapted to receive a threaded portion, the threaded portion being adapted to selectively engage with a threaded section in an open end of the downhole tubular; and at least two removable and interchangeable threaded portions of different dimensions.

70. The kit of parts for the connector as claimed in claim 69, wherein the extendable portion is adapted to receive a seal at or towards its free end, the seal being adapted to selectively sealingly engage the downhole tubular; and the kit further comprises at least two removable and interchangeable seals of different dimensions.

71. A method for providing a fluid tight connection between a fluid supply and a downhole tubular using a connector, the connector comprising: an extendable portion and a body portion, the extendable portion having a seal at or towards its free end which is adapted to selectively sealingly engage the downhole tubular; and a threaded portion provided on the body portion; the threaded portion being adapted to selectively engage with a threaded section of the downhole tubular; wherein the method comprises the step of:

(a) engaging at least one of the seal and the threaded member with the downhole tubular.

72. The method as claimed in claim 71, wherein prior to step (a) the method comprises the additional step of:

(b) exchanging the seal for a second seal.

73. The method as claimed in claim 71 or 72, wherein prior to step (a) the method comprises the additional step of:

(c) exchanging the threaded member for a second threaded member.

74. The method as claimed in any one of claims 71 to 73, wherein after step (a) the method comprises the additional step of:

(d) swapping the engagement of the threaded member with the downhole tubular to an engagement of the seal with the downhole tubular.

75. The method as claimed in any one of claims 71 to 74, wherein after step (a) the method comprises the additional step of:

(e) swapping the engagement of the seal with the downhole tubular to an engagement of the threaded member with the downhole tubular.

76. The method as claimed in any one of claims 71 to 75, wherein after step (a) the method comprises the additional step of:

(f) rotating the downhole tubular.

77. The method as claimed in any one of claims 71 to 76, wherein after step (a) the method comprises the additional step of:

(g) applying drilling fluid to the downhole tubular.

78. The method as claimed in any one of claims 71 to 77, wherein at least one of the seal and the threaded member are engaged in the open end of the downhole tubular.