Improvements in and relating to core sample drilling

Abstract

The present invention relates to a non-rotating coupling system for connecting / separating adjacent innertubes in a drill string in a core drilling rig in a faster / safer and more accurate way without causing rotation of the adjoining up and downstream inner tubes or the core sample.

Description

[0001] IMPROVEMENTS IN AND RELATING TO CORE SAMPLE DRILLING

[0002] Statement of corresponding applications

[0003] This application is based on the specification filed in relation to Australian Patent Application Number 2024901697, the entire contents of which are incorporated herein by reference.

[0004] Technical Field

[0005] This invention relates to improvements in and relating to core sample drilling.

[0006] This invention relates to a core sampling drill rig as well as a device for handling a core sample during a drilling operation, to recover and remove the core sample from the drill rig, and a method for recovering core samples from a formation. This invention also includes parts and fittings, and unique method steps, related to said improvements.

[0007] Background

[0008] A drill rig capable of rotating a hollow (doughnut shaped) diamond impregnated drill bit at high speed is generally used when drilling to recover a rock core sample. A core sample is recovered for analysis to determine if any valuable minerals are present. Due to the use of a diamond impregnated drill bit, the drilling process for recovering core samples is typically referred to as 'diamond drilling'.

[0009] The drill bit is attached to a hollow drill string made up of drill rods threaded together end-to-end. An inner tube is provided within the hollow drill string to receive and hold the drilled core sample as the drill string and drill bit are advanced into the ground. The drill rig is equipped with a wireline retrieval system allowing the core sample to be periodically pulled to the surface for geotechnical analyses. The wireline retrieval system includes an overshot system connected to a wireline winch to allow the core samples to be recovered from deep in the ground without needing to remove the drill rods from the ground. At the lower end of the drill string (but above the drill bit) there is an outer barrel - a heavy walled drill rod. Nestled within the outer barrel is an inner tube for receiving the core sample as the drill string is advanced into the formation. At the bottom end of the inner tube there is a core catcher.

[0010] The core catcher (or core lifter) stops the core sample from falling from the inner tube when the inner tube is pulled to surface. A head assembly is connected by a threaded connection to the top of the inner tube.

[0011] The head assembly incorporates a latching device that holds the inner tube in place within the drill string as the core sample advances into the inner tube. The head assembly also includes a swivel assembly which stops the inner tube from rotating with the drill bit, outer barrel and drill rods to prevent damage to the core sample.

[0012] A spear point incorporated to the head assembly allows an overshot system to be lowered down the inside of the drill rods on a wireline at the completion of each drill run (equal to the length of each drill rod - usually 3 meters long).

[0013] The overshot system latches onto the spear point to allow the inner tube with the core sample to be retrieved to the surface for emptying / and geotechnical analyses. The above process of drilling and recovering the inner tube via wireline is well understood within the industry and is not expanded upon further.

[0014] It is important to provide geologists with as much geological data as possible. Important data includes the depth and angular orientation of the core sample.

[0015] It has therefore become normal to run orientation tools down hole. An orientation tool, usually an electronic device, is attached to the top of the inner tube, between the inner tube and the head assembly, and records the angular orientation (usually the bottom dead centre of the core sample as it was prior to being drilled and removed from the formation) of the core sample prior to being removed from the inner tube.

[0016] The orientation information must be determined prior to removal of the orientation tool from the inner tube. The components are typically connected by threads, and so are separated by rotating one component relative to the other. When the core sample is pulled to surface (e.g., by a wireline and winch), it is critical that the orientation device records the orientation of the core sample as it was prior to being removed from the formation - before any threads are undone to allow the subsequent removal of the core sample.

[0017] This above describe system works well and has been in use for decades, however the core drilling process is slow and expensive.

[0018] The core drilling process is made up of the following steps:

[0019] 1. The drill rig rotates the drill rods and drill bit into the formation for the length of a string of drill rods.

[0020] 2. The wireline and overshot is lowered down the inside of the drill rods and attaches to the spear point on the head assembly (on the end of the terminal inner tube adjacent the drill bit)

[0021] 3. The wireline pulls the string of inner tubes and core sample within to the surface and the core sample is removed.

[0022] 4. An empty string of inner tubes is dropped down the inside of the drill rods an latches in place adjacent to the drill bit.

[0023] 5. Drilling resumes and the process 1-4 is repeated until the desired depth is achieved.

[0024] Due the considerable time consumed in steps 2-4, time spent actually advancing the drill bit into the formation could be as little as 30% - and this non-productive time gets longer the deeper the bore advances.

[0025] The non-productive time has long been recognised as a driver for high costs and there have been recent developments to try to minimise this down time. One particularly promising method is described in PCT / NZ2021 / 050210 which allows for the safe handling of long connected lengths of inner tubes, resulting in long core runs (e.g. 12meters plus instead of the typical 3-meter runs) dramatically increasing productivity.

[0026] It is an object of the present invention to address any one or more of the above problems or to at least provide the industry with a useful choice. However, to enable this process to be safely undertaken there is a need for a method / system and components therefor that allow the inner tubes (and entrapped core sample) to be separated from each other without relative rotation between the inner tubes or core sample(s).

[0027] As the primary objective of the very expensive core sampling process is to provide as much accurate geological data as possible. The risk of losing the orientation of the core sample or providing an inaccurate indication of the core sample orientation is unacceptable in terms of meeting this objective.

[0028] The reference to any prior art in the specification is not, and should not be taken as, an acknowledgement or any form of suggestion that the prior art forms part of the common general knowledge in any country.

[0029] Disclosure of Invention

[0030] According to a first aspect of the present invention there is provided a coupling system for a core drilling rig, providing machine connecting and separating of adjacent innertubes without any rotation thereof, the coupling system thereby enhancing core orientation accuracy by eliminating relative rotation between the inner tubes and / or core sample, during disconnection of the adjacent inner tubes- wherein the system includes:

[0031] - at least two adjacent inner tubes each associated with an anti-rotation device to prevent rotation thereof; a joiner sleeve placed between the adjacent inner tubes, the outer surface of the joiner sleeve adapted to be rotationally driven; and

[0032] - at least one driving unit which has been adapted to engage an outer surface of a joiner sleeve so as to be capable rotating the joiner sleeve wherein the joiner sleeve has left-handed thread at one end thereof, and has a right- handed thread at the other end thereof, the threads at the respective ends of the joiner sleeve having the opposite handedness to one another so when: the anti-rotation devices are engaged; the joiner sleeve can be rotated in either a clockwise or anti-clockwise direction depending on whether separation of connection is required.

[0033] It will be appreciated that whether the threads used on the joiner sleeve are internal or external threads will depend on whether an internal or external thread is used on the innertubes to which the joiner sleeve connects.

[0034] According to a second aspect of the present invention there is provided a coupling system substantially as described above including the following additional components:

[0035] - at least two connector sleeves which attach to either end of the joiner sleeve; wherein one connector sleeve has an internal / external thread which is left-handed at one end thereof for attachment to one end of the joiner sleeve, and wherein the other connector sleeve has an internal / external thread which is right-handed at one end thereof for attachment to the other end of the joiner sleeve; wherein the other end of the respective connector sleeves -for attaching to the respective adjacent innertubes, will be the same handed thread as each other, either a right- or lefthanded thread, depending on the handedness of the threads on the respective end of each inner tube to which each connector sleeve attaches, wherein the handedness of the thread on each adjacent innertube is the same.

[0036] In embodiments where there is two or more connector sleeves the additional sleeves which replicate the threads and handedness of those on the connector sleeve(s) to which they are connecting The applicant has found the advantage of using one or more connector sleeves is that these act as sub-savers and help protect the thread on the expensive to manufacture joiner sleeve and can be easily and cost effectively be replaced, rather than machining a new joiner sleeve.

[0037] According to a second aspect of the present invention there is provided a driving unit which includes a driven roller which is adapted to engage the outer surface of a joiner sleeve so as to be capable of rotating the joiner sleeve to threadably engage or disengage connector sleeves and / or innertubes di rectly / i ndi rectly connected thereto.

[0038] According to a third aspect of the present invention there is provided a joiner for non-rotating separation of adjacent innertubes in a drill string in a core drilling rig, the joiner including an outer surface adapted to be rotationally driven and wherein the joiner sleeve has left-handed thread at one end thereof and has a right-handed thread at the other end wherein the length of the thread at one end of the joiner sleeve is longer than the length of thread at the opposite end of the joiner sleeve - so that in practice only one end completely uncouples to expose a section of core sample for subsequent cutting.

[0039] According to a further aspect of the present invention there is provided a joiner or coupling system substantially as described above whereby the internal and external diameter of the joiner sleeve substantially are the same diameters as the internal and external diameters as the inner tubes.

[0040] According to a fourth aspect of the present invention there is provided a coupling system as claimed in claim 1 wherein the driving unit(s) include: at least one roller including ridges and troughs on the outside thereof presented in the form of a helix; and wherein the joiner sleeve includes corresponding ridges and troughs on the outside thereof presented in a matching helix to those on the roller, so as to provide positive mesh engagement with the joiner sleeve to enable rotation of the sleeve via the driving unit(s).

[0041] The applicant has found that the matching helix spirals on the outer surface of the driven roller and joiner sleeve helps provide a 'judder free" rotational coupling / uncoupling of the innertubes Particularly if the driven rollers "walk" off the machined helix onto the smooth portion of the joiner sleeve and or the inner tubes According to a fifth aspect of the present invention there is provided a core drilling rig which includes:

[0042] - an upstream innertube clamp;

[0043] - a downstream innertube clamp;

[0044] - a driving unit which is situated intermediate the upstream and downstream innertube clamps, wherein said driving unit has been adapted to engage and outer surface of a joiner sleeve so as to be capable rotating the joiner sleeve. wherein both of upstream and downstream innertube clamps are configured to rotationally constrain the inner tubes - but at least one of the clamps can move longitudinally with respect to the threads being connected or separated.

[0045] Preferably, the driving unit includes at least one driven roller which has an outer surface with projections and / or recesses which in use can engage with projections and / or recessions on the outer surface of the joiner sleeve to rotate the joiner sleeve.

[0046] Unless the context clearly requires otherwise, throughout the description and the claims, the words "comprise", "comprising", and the like, are to be construed in an inclusive sense as opposed to an exclusive or exhaustive sense, that is to say, in the sense of "including, but not limited to".

[0047] Where in the foregoing description, reference has been made to specific components or integers of the invention having known equivalents, then such equivalents are herein incorporated as if individually set forth.

[0048] The invention may also be said broadly to consist in the parts, elements and features referred to or indicated in the specification of the application, individually or collectively, in any or all combinations of two or more of said parts, elements or features, and where specific integers are mentioned herein which have known equivalents in the art to which the invention relates, such known equivalents are deemed to be incorporated herein as if individually set forth.

[0049] Further aspects of the invention, which should be considered in all its novel aspects, will become apparent from the following description given by way of example of possible embodiments of the invention. Brief description of the drawings

[0050] An example embodiment of the invention is now discussed with reference to the Figures.

[0051] Fig 1 shows a non-rotating coupling system forming part of a core drilling rig in accordance with one embodiment of the present invention; (non-rotating refers to the fact the while the joiner sleeve is rotated - the up and down stream connected inner tubes do not rotate.

[0052] Fig 2 shows the adjacent innertubes in Figure 1 after one innertube has been disconnected from the joiner for retrieval of the core sample, while the second inner tube is still partially connected to the joiner system;

[0053] Fig 3 shows the mast of the drilling rig and the position of the two anti-rotation clamps for holding the adjacent downstream and upstream innertubes held by the joiner sleeve of the present invention which is rotated by a driving unit situated transversely adjacent the joiner sleeve to connect / disconnect the adjacent innertubes.

[0054] Fig 4 shows a joiner sleeve as shown in Figures 1 -3 in more detail and also shows an optional use of a sub-saver (connector) sleeve according to a preferred embodiment of the present invention.

[0055] Fig 5 is similar to Figure 2 but shows an alternate embodiment of the present invention which solely utilises a joiner sleeve and is not using connector sleeves as shown in Figures 1 and 2.

[0056] Best modes for carrying out the Invention

[0057] With respect to Figure 1 the non-rotating coupling system 1 has a joiner sleeve 2 indirectly connected via connector sleeves 3 and 4 to adjacent innertubes 5 and 6 these tubes respectively being downstream and upstream with respect to the travel of the core sample along a string of connected innertubes from the drill tip.

[0058] The joiner sleeve 2 is threadably connected at either end thereof to connector sleeves 3, 4. The connector sleeves 3, 4 being also threadably connected - at the opposite ends thereof - to the respective ends of adjacent innertubes 5,6 which have been either:

[0059] - slid out of the drill rods (not shown) for retrieval of the core sample within the inner tubes; or

[0060] - connected to one another, via the joiner sleeve 2 for insertion into the drill rods (not shown).

[0061] As will be described, in use, the joiner sleeve 2 is rotated by a motorised driving unit (not shown in Figure 1) to threadably connect adjacent innertubes 5 and / or 6 via the connector sleeves 3,4 which have been pre-threaded onto the respective ends of the adjacent innertubes 5,6 to the respective internal threads at either end of the joiner sleeve 2.

[0062] As can be seen in Figure 1 and Figure 2 the joiner sleeve 2 has a grooved outer surface 7 which comprises a series of parallel grooves 8 and ridges 9, in the preferred embodiment the grooves are formed as a partial helix with a 1.5m pitch which we have found gives good torsional traction with a smooth rotation (but in practice any angle could work)

[0063] In Figure 2 to facilitate exposure of a section the core sample 10 for rapid retrieval and maximisation of core sample integrity - in particular sample orientation within the inner tube - the internal it is preferable to have one section of thread e.g., 109 / 110 shorter than the opposite threads 111 (not shown) / 112. As this allows the core sample to be exposed, to enable subsequent cutting and removal - while only disengaging one thread, thereby the remaining assembly (i.e., innertube 6, connector sleeve 4 joiner sleeve, 2 to remain rigid and safe for subsequent offloading for core removal.

[0064] In preferred embodiments it is also preferable to keep the connector sleeves fully threadably engaged to an adjacent innertube whilst the joiner sleeve is disconnecting the adjacent innertube.

[0065] In one example, the upstream connector sleeves may be kept in fully threadable contact with the adjacent innertube - during disconnection of the other adjacent innertube - via an adhesive such as LOCKTITE™ or other suitable bonding / retarding agent / mechanism which is / can be applied to the innertube / connector sleeve threadable connections, to retard this connection being rotated and thus unthreaded unless a higher torque force is applied. In another example, the downstream connector sleeves may be kept in fully threadable contract with the adjacent innertube - during disconnection of the other adjacent downstream innertube - via a higher torque setting being used, when the connector sleeve to the upstream innertube, than is used for connecting the joiner sleeve to a connector sleeve.

[0066] It should be noted that once a section of the core sample 10 is exposed it can be cut for retrieval thereof.

[0067] Figure 3 shows a portion of the drill rig 100 which includes the non-rotational coupling system 1 of the present invention.

[0068] The drill rig 100 has a drill mast 200 and two anti-rotation clamps 103, 104 which are situated on the mast 101 on either side of a motorised driving unit 105 which rotates - via a driven roller(s) 106 - the joiner sleeve 2 in either a clockwise or anticlockwise direction depending on whether one is connecting the joiner sleeve 2 to innertubes 5,6 or disconnecting the innertubes 5,6 from the joiner sleeve 2 for core sample retrieval.

[0069] The driven roller has series of ridges of grooves on the outer surface which are adapted to correspond with the ridges and grooves 8,9 of the grooved outer surface 7 on the joiner sleeve so as to be capable of meshing therewith when the driven roller and joiner sleeve are bought into contact with one another as shown by double headed arrow Y. The driven roller(s) 106 is / are moved in direction Y via a linear actuator (not shown) which has the contact force with the joiner sleeve controlled by an adjustable arrangement, which can be by means of a pressure sensor, which may be the same arrangement as used on conventional drive rollers used on drill rigs to unscrew rods / tubes as is known in the art. The grooved outer surface has been found to be effective in providing maximum torsional drive with minimal crushing pressure on the thin-walled joiner sleeve.

[0070] It should be noted in Figure 3 there is also a second opposed driven roller (optional) (not shown) on the opposite side of the joiner sleeve which can also be bought into contact with the joiner sleeve's grooved surface 7 as also shown by the second double headed arrow Y.

[0071] The anti-rotation clamps 103, 104 can longitudinally float, in an upstream or downstream longitudinal direction - as shown by double headed arrow Z (or if required be driven) on tracks 107 on drill mast 200 - to enable the thread joining / separation of the inner tubes 5,6 from the joiner sleeve and exposure of the core sample for cutting via a core cutting assembly as shown by arrow

[0072] 108 to enable the core sample 10 to be cut for retrieval and subsequent analysis.

[0073] Example 1 - connecting adjacent inner tubes 5 and 6

[0074] With reference to the drill rig 100 as generally depicted in Figure 3 the driven roller 106 rotates in an anticlockwise direction (i.e. to left hand side of Figure 2) in order to rotate the joiner sleeve 2 in a clockwise direction when the respective ridges and grooves on the driven roller 106 and joiner sleeve 2 mesh together. The drive unit 105 being capable of being moved transversely in the direction shown by double headed arrow Y to bring the drive roller 106 into and out of engagement with the joiner sleeve 2. Directions of rotation could be the reverse of the above depending on the handedness of attached components

[0075] Example 2 - disconnecting inner tube 5 from the joiner sleeve 2

[0076] With reference to the drill rig 100 as generally depicted in Figure 3 the driven roller 106 rotates in a clockwise direction (i.e. to left hand side of Figure 2) in order to rotate the joiner sleeve 2 in an anticlockwise direction when the respective ridges and grooves on the driven roller 106 and joiner sleeve 2 mesh together. The drive unit 105 being capable of being moved transversely in the direction shown by double headed arrow Y to bring the drive roller 106 into and out of engagement with the joiner sleeve 2.

[0077] Directions of rotation could be the reverse of the above depending on the handedness of attached components

[0078] Once the core sample 10 has been exposed and cut by the core cutter 108 - the upper length of inner tube 6 and connector sleeve 4 and joiner sleeve 2 can be offloaded from the drill mast and the core sample can be slid out of the inner tube 5 for capture and subsequent analysis

[0079] This process can be repeated as the next adjacent innertube (not shown) upstream of innertube 6 and connected thereto by another joiner sleeve (not shown) is slid in a downstream direction from the drill rods (not shown) of the drilling rig. Example 3 - Joiner Sleeve and Driven Roller

[0080] In a preferred embodiment the joiner sleeve may be 3mm thick and have 1mm deep groves formed in a partial helix with a 1.5 metre pitch, the driven roller will have a matching helix, and grooves.

[0081] In Figures 1 and 2 the internal thread 109 on the downstream end of joiner sleeve 2 and the external thread 110 on connector sleeve 3 are both right-handed. Conversely, the internal thread 111 at the upstream end of joiner sleeve 2 connecting to external thread 112 of upstream external connector sleeve 4 are both left-handed. The upstream inner tube 6 connects to the connector sleeve 4 via a right-handed thread and the downstream inner tube 5 connects to the connector sleeve also by a right-handed thread.

[0082] It will be noted the handedness of the threads discussed above is configured for when the joiner sleeve 2 is rotated in the direction indicated by arrow X which is anti-clockwise if one is viewing the innertube string looking in an upstream direction.

[0083] Figure 4 shows the joiner sleeve 2 separated from connector sleeves 3,4 with threads as described above for Figure 2 with like reference numerals being used for same.

[0084] In addition to what is shown in Figure 2, what Figure 4 shows is internal right-handed thread 111 on connector sleeve 3 which in use threadably engages a right-handed external thread (not shown) on inner tube 5.

[0085] Additionally, Figure 4 shows a further connector sleeve 11 which is used as a sub saver to help protect the internal thread in the joiner sleeve 2. The connector sleeve 11 has an external right handed thread 113 and an internal right-handed thread 114. As can be seen it is identical to connector sleeve 3.

[0086] With respect to Figure 5 the non-rotating coupling system 100 has a joiner sleeve 20 directly connected to adjacent terminal innertubes 5 and 6 these tubes respectively being downstream and upstream with respect to the travel of the core sample along a string of connected innertubes from the drill tip. The joiner sleeve 20 is threadably connected at either end thereof to innertubes 5 and 6. The joiner sleeve has an internal right-handed thread 109 at one end thereof which connects to an external right-handed thread on innertube 5. The joiner sleeve also has an internal thread (not shown) which is left-handed and connects to an external left-handed thread 112 on innertube 6. The respective internal diameters at either end of the joiner sleeve are the same diameter as respective external diameters of the inner tubes 5,6.

[0087] In use, the joiner sleeve 20 is rotated by a motorised driving unit (not shown in Figure 5) to threadably connect adjacent innertubes 5 and / or 6. During the rotation of the joiner sleeve 20 by the driving unit the innertubes 5 and 6 and held rotationally stationary by clamps not shown in Figure 5. At least one of the clamps being adapted to be longitudinally slid or to float to allow the threads to engage or separate.

[0088] In Figure 5 to facilitate exposure of a section the core sample 10 for rapid retrieval and maximisation of core sample integrity so as to maintain the original sample orientation within the innertube, and to maintain system rigidity for safe handling it is preferable to have one section of thread 110 shorter than the opposite thread 112 on the innertubes 5,6. Correspondingly, the joiner sleeve also has a shorter internal thread 109 at one end thereof connecting to innertube 5 than the internal thread (not shown) at the other end of the joiner 20 which connects to thread 112 on the innertube 6.

[0089] This thread configuration on the joiner sleeve and innertubes allows the core sample to be exposed, to enable subsequent cutting and removal - whilst only disengaging one thread on a single innertube from the joiner sleeve.

[0090] Examples of some Alternate Ways to Implement the Present Invention

[0091] The joiner sleeve may have its outer surface adapted to be rotationally driven in a number ways. In one example the joiner sleeve may have an outer surface which has a series of circumferentially spaced apart parallel grooves and ridges, which in use can mesh with a corresponding series of circumferentially spaced apart parallel grooves and ridges on a motor driven roller associated with the mast of a drill rig.

[0092] In another example the joiner sleeve may have an outer surface which joiner sleeve may have a series of spaced apart recesses across its surface, which in use can mesh with a corresponding series of spaced apart projections on the surface of a motor driven roller associated with the mast of a drill rig-

[0093] In one embodiment the joiner sleeve may have the series of circumferentially spaced apart parallel longitudinally extending grooves and ridges having a longitudinal axis which is parallel to the longitudinal axis of the sleeve.

[0094] In a preferred embodiment the joiner sleeve may have the series of circumferentially spaced apart parallel extending grooves and ridges which have a longitudinal axis which extends at an acute angle to the longitudinal axis of the joiner sleeve.

[0095] In one example the joiner sleeve may have a smooth outer surface and be rotated by any suitable means (rollers / rotational clamps etc) whereby the rollers / clamps may have a surface treatment to provide adequate torque to rotate the joiner sleeve.

[0096] As will be appreciated by those skilled in the art there are numerous surface features that could be applied to either (or both) of the driving mechanism and the joiner sleeve to achieve the necessary traction. The exact means by which the driving mechanism is arranged is not essential to the present invention provided it can achieve the stated objective of coupling or uncoupling a threaded connection between the connector sleeve(s) and the joiner sleeve.

[0097] The acute angle of the grooves and ridges relative to the longitudinal axis of the joiner sleeve may vary without departing from the scope of the present invention.

[0098] The joiner sleeve and the outer surface of the joiner sleeve may also have other configurations which enable a connection capable of driving the joiner sleeve to rotate in a desired rotational direction. The key factor being the engagement between the driven roller and the outer surface of the joiner sleeve being capable of rotating the joiner sleeve to connect / disconnect the innertubes via its direct or indirect interface with same.

[0099] The anti-rotation device may come in a variety of different forms.

[0100] In one example the anti-rotation device may be configured as a clamp which applies pressure to grip and prevent rotation.

[0101] In another example the anti-rotation device may be in the form of a stop which can be moved to engage or disengage with a spline on the outer surface of the innertube near the threaded end to prevent rotation of the innertube.

[0102] Benefits

[0103] The time taken to couple inner tubes together to form a string of inner tubes, and retrieving the string of inner tubes, uncoupling, separating, cutting / breaking and unloading the inner tubes from the rig may take longer than handling a single inner tube. However, the time taken to retrieve a single inner tube with core sample to the surface is significantly longer, such that a significant overall time saving is expected, with a resulting improvement in drill rig utilisation.

[0104] Being able to maintain the integrity of the core sample in a drill string by eliminating the relative rotation of the inner tubes and core sample when separating multiple innertubes whilst still enabling mechanically driven quicker and safer disconnection of innertubes for retrieval of the core sample is a considerable benefit of this system.

[0105] Providing a system that does not rely on alignment dogs, splines, seals etc lends itself to mechanical / hands free system which can connect / disconnect adjacent innertubes in a string of innertubes this creates significant time savings, and considerable safety benefits compared to conventional means of connection / disconnection.

[0106] Providing a system which enables innertubes to be connected without the need for seals, splines or dogs again provides time savings compared to conventional means of connection / disconnection. Although this invention has been described by way of example and with reference to possible embodiments thereof, it is to be understood that modifications or improvements may be made thereto without departing from the spirit or scope of the appended claims.

Claims

What we claim is:

1. A coupling system for a core drilling rig, providing machine connecting and separating of adjacent innertubes without any rotation thereof, the coupling system thereby enhancing core orientation accuracy by eliminating relative rotation between the inner tubes and / or core sample, during disconnection of the adjacent inner tubes- wherein the system includes:- at least two adjacent inner tubes each associated with an anti-rotation device to prevent rotation thereof; a joiner sleeve placed between the adjacent inner tubes, the outer surface of the joiner sleeve adapted to be rotationally driven; and- at least one driving unit which has been adapted to engage an outer surface of a joiner sleeve so as to be capable rotating the joiner sleeve wherein the joiner sleeve has left-handed thread at one end thereof, and has a right- handed thread at the other end thereof, the threads at the respective ends of the joiner sleeve having the opposite handedness to one another so when: the anti-rotation devices are engaged; the joiner sleeve can be rotated in either a clockwise or anti-clockwise direction depending on whether separation of connection is required.

2. A coupling system as claimed in claim 1 wherein the driving unit(s) include: at least one roller including ridges and troughs on the outside thereof presented in the form of a helix; and wherein the joiner sleeve includes corresponding ridges and troughs on the outside thereof presented in a matching helix to those on the roller, so as to provide positive mesh engagement with the joiner sleeve to enable rotation of the sleeve via the driving unit(s).

3. A coupling system as claimed in any of the preceding claims including the following additional components:- at least two connector sleeves which attach to either end of the joiner sleeve; wherein one connector sleeve has an internal / external thread which is left-handed at one end thereof for attachment to one end of the joiner sleeve, and wherein the other connector sleeve has an internal / external thread which is right-handed at one end thereof for attachment to the other end of the joiner sleeve; wherein the other end of the respective connector sleeves -for attaching to the respective adjacent innertubes, will be the same handed thread as each other, either a right- or lefthanded thread, depending on the handedness of the threads on the respective end of each inner tube to which each connector sleeve attaches, wherein the handedness of the thread on each adjacent innertube is the same.

4. A joiner for non-rotating separation of adjacent innertubes in a drill string in a core drilling rig, the joiner including an outer surface adapted to be rotationally driven and wherein the joiner sleeve has left-handed thread at one end thereof and has a right-handed thread at the other end wherein the length of the thread at one end of the joiner sleeve is longer than the length of thread at the opposite end of the joiner sleeve.

5. A joiner or coupling system as claimed in any of the preceding claims whereby the internal and external diameter of the joiner sleeve are the same diameters as the internal and external diameters as the inner tubes.

Images