Improvements in and relating to up-hole core sample drilling

Abstract

A core drilling rig adapted for up-hole (i.e. above vertical) drilling, which includes a core drilling apparatus for a string of drill rods / innertubes, comprising: a drill mast; a string of drill rods; a string of inner tubes; a drill bit on distal end of uppermost drill rod; a foot clamp which can hold the weight of drill rods and drill bit; and a first rotation device and a slide unit; the first rotation device being capable of rotating and connecting / disconnecting (i.e., threading / unthreading) drill rods from the drill string as required with the assistance of the slide unit; wherein the drill rig is characterized in that it further includes a handling device comprising: an inner tube clamp; a core cutter and optionally a retainer device; wherein once the core sample has been cut to release the lowermost section of the core sample, the core cutter or retaining device, is configured to retain any remaining uphole lengths of core sample and inner tubes with respect to the drill string; a second rotation device and optionally an associated slide unit; and a core / lowermost innertube (CLI) capture device configured to receive the core / lowermost innertube in a controlled manner.

Description

[0001] IMPROVEMENTS IN AND RELATING TO UP-HOLE CORE SAMPLE DRILLING

[0002] Technical Field

[0003] This invention relates to improvements in and relating to up-hole core sample drilling.

[0004] 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 up-hole core sample from the drill rig, and a method for up-hole drilling and recovering up-hole core samples from a formation. This invention also includes parts and fittings, and unique method steps, related to said improvements.

[0005] 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'.

[0006] 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.

[0007] Core sample drilling using a drill rig with a string of drill rods and a string of inner tubes is a recent innovation and is known in the art as it forms the basis of the present applicant's earlier PCT Application. WO 2022 / 119455.

[0008] Notwithstanding, the advances in the art, in core sample drilling, made by the applicant in WO 2022 / 119455 - there still remains a problem in the art - when, if comes to drilling for core samples in a substantially upward direction (known in the art as up-hole drilling) - [i.e., drilling a substrate in a direction which is above the horizontal]. Up-hole core drilling, as opposed to standard downward core drilling into the earth, poses significant risks due to the weight of the core sample and / or inner tube(s) - potentially hundreds of kilograms that are located above drill workers. The core sample and / or the inner tubes have the potential to become a spear like shaft, if they were to fall and become accelerated by gravity, and for this reason therefore pose a serious injury risk, or even worse a mortality risk, to workers operating the rig, and or damage to equipment.

[0009] This injury / mortality risk means in practice when undertaking up-hole core sample drilling using conventional methods and machinery only short core samples are taken -i.e., typically 3m maximum in length (and not via connected inner tubes) - to help reduce the aforementioned risk of injury or death.

[0010] Having longer effective lengths of inner tubes via string thereof would increase the efficiency of drilling and core sample recovery, provided safety concerns could be addressed, without compromising core sample quality (i.e. maintaining the integrity of a core sample) which will be severely compromised if the core sample were to uncontrollably fall due to gravity as aforementioned.

[0011] 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.

[0012] Disclosure of Invention

[0013] 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.

[0014] According to a first aspect of the present invention there is provided a core drilling rig adapted for up-hole (i.e. above vertical) drilling, which includes a core drilling apparatus for a string of drill rods / innertubes, comprising:

[0015] • a drill mast;

[0016] • a string of drill rods;

[0017] • a string of inner tubes;

[0018] • a drill bit on distal end of uppermost drill rod; • a foot clamp which can hold the weight of drill rods and drill bit; and

[0019] • a first rotation device and a slide unit; the first rotation device being capable of rotating and connecting / disconnecting (i.e., threading / unthreading) drill rods from the drill string as required with the assistance of the slide unit; wherein the drill rig is characterized in that it further includes a handling device comprising:

[0020] • an inner tube clamp;

[0021] • a core cutter and optionally a retainer device; wherein once the core sample has been cut to release a lowermost section of the core sample, the core cutter or retaining device, is configured to retain any remaining core sample and inner tubes in position with respect to the drill string;

[0022] • a second rotation device and optionally an associated slide unit; and

[0023] • a core / lowermost innertube (CLI) capture device configured to receive the core / lowermost innertube in a controlled manner.

[0024] A core drilling rig substantially as described above wherein the CLI capture device includes a clamp which prevents movement of the CLI capture device relative to the longitudinal axis of the mast.

[0025] In some embodiments, the device comprises a positioning apparatus not shown configured to move the clamp away from the mast for retrieval of the core sample from the drilling rig. Positioning apparatus may include a driver device, and optionally a track or pivot arrangement, which enable movement of the clamp away from the mast.

[0026] The first rotation device is known in the art, and may primarily be, for attaching or detaching drill rods in a drill string whereas the second rotation device may be for attaching or detaching inner tubes. Thus, in some embodiments the first rotation device may be used for unwinding inner tubes in a counter rotation embodiment discussed below.

[0027] In such embodiments the first rotation device will have two operating positions to take into account the different outside diameters of the rods and inner tubes it has to grip and rotate.

[0028] The following discussion therefore will - while not exclusively - in particular focus on the new second rotation device. In some embodiments, the first or second rotation device is configured to grip the outside of rods / inner tubes as required to rotate the upper rod and / or inner tube to uncouple the upper rod and / or upper inner tube from the adjacent lower rod or lower inner tube - as the case may be.

[0029] In some embodiments, the rotation device is configured to rotate the upper rod or upper inner tube to couple the upper rod or upper inner tube to the adjacent lower rod or lower inner tube.

[0030] In some embodiments, the first and second rotation device(s) may comprise(s) a pair of jaws moveable between an open position and a closed position, each jaw of the pair of jaws comprising at least one roller configured to rotate, and wherein in the closed position the rollers engage the upper rod or upper tube and are driven by a driver such as a motor to rotate to uncouple or couple the upper rod / upper tube from the adjacent lower rod / inner tube.

[0031] Alternatively, the rollers can engage and rotate the lower rod or lower inner tube to couple / uncouple.

[0032] It will be appreciated that the slide unit(s) will move the rotation device longitudinally along the mast as required to thread / unthread and a clamp will hold the adjacent rod / inner tube.

[0033] Furthermore, in one embodiment first and second rotation devices and first and second slider units may be employed to thread / unthread adjacent upper and lower rods / inner tubes

[0034] In some embodiments, the device comprises a cutting or breaking mechanism, to cut or break an exposed portion of the core between the upper and lower inner tubes after the upper and lower inner tubes have been uncoupled and separated.

[0035] In some embodiments, the cutting or breaking mechanism comprises at least one blade or at least one chisel movable between a retracted position and an extended position to cut or break through the core sample.

[0036] In some embodiments there may be a pair of opposed blades or opposed chisels wherein each blade / chisel of the pair is moveable between a retracted position and an extended position. In some embodiments, the device comprises a marking mechanism to provide a longitudinal mark to an exposed portion of the core between the upper and lower inner tubes after the upper and lower inner tubes have been uncoupled and separated, to preserve a known orientation of adjacent portions of the core after cutting or breaking.

[0037] In some embodiments, the marking mechanism is mounted below and in fixed relation to the coupling mechanism.

[0038] In some embodiments, the marking mechanism is located axially between the coupling mechanism and the breaking or cutting mechanism.

[0039] In some embodiments the core cutting / breaking mechanism provides a "witness" mark on the core sample allowing for subsequent core realignment (away from the drill rig) - without the need for a separate marking mechanism.

[0040] The core / lowermost innertube (CLI) capture device may be configured to receive the core / lowermost innertube in a controlled manner in variety of ways without departing from the scope of the present invention.

[0041] In one embodiment the CLI capture device may include a plug and cylinder or trolley and channel arrangement, the plug and cylinder being adapted relative to one another so the cylinder can slowly receive the innertube and core sample therein, notwithstanding the weight thereof and pull of gravity thereon. In one such embodiment the plug may have an outer diameter which may have a close tolerance to the internal walls of the cylinder such that the plug causes resistance to movement down the cylinder due to:

[0042] A compressible fluid in the cylinder which must be compressed; or

[0043] An incompressible fluid in the cylinder which must be displaced via a vent or restricted exit port; or

[0044] An incompressible fluid which may be displaced via passing by the plug in order to exit the cylinder via the top thereof.

[0045] In some embodiments this could also be accomplished with a spring combined with the CLI In another embodiment the CLI capture device may include a trolley which has rollers or wheels which travel along a channel the trolley having to compress a compression spring located in said channel.

[0046] According to a second aspect of the present invention there is provided a method of up hole drilling for core samples utilising a string of at least two inner tubes and which provides a safe manner for retrieving core samples from said string of inner tubes, and separating said string at the drill rig , the method comprising the steps of: a) releasing the inner tubes from the drill string; b) receiving the lowermost inner tube in a capture device; c) clamping lowermost inner tube; d) rotating an adjacent upper inner tube relative to an adjacent lower inner tube (or vice versa) to detach the lower inner tube from the string of inner tubes, or rotating each inner tube in counter directions to one another to detach the lower inner tube from the string of inner tubes; e) sliding the lowermost tube relative to the adjacent upper most tube (or vice versa), or sliding both of these inner tubes away from each other, to expose a portion of the core sample; f) cutting the core sample; g) retaining the balance of uphole core sample(s) in the uppermost string of inner tubes; h) moving the capture device to allow for retrieval of core sample from drill rig; i) moving the capture device to be adjacent the lowermost inner tube; j) repeating steps a) to h) until the entire core sample has been retrieved from the drill rig at step f).

[0047] In some preferred embodiments, the string of inner tubes comprises more than two inner tubes.

[0048] The adjacent inner tubes in a string being rotationally coupled to one another.

[0049] In some embodiments, each inner tube comprises a thread at each end, and in step (iii) the method comprises coupling the next inner tube to the upper end of the inner tube received in the drill string by rotating and threading the next inner tube to the upper end of the inner tube received in the drill string, and in step (iv) the method comprises uncoupling the uppermost inner tube from the adjacent second uppermost inner tube by rotating and unthreading uppermost inner tube from the second uppermost inner tube.

[0050] In some embodiments, the method comprises an additional step of providing a longitudinal mark to the exposed portion of the core between the upper and lower inner tubes after the upper and lower inner tubes have been uncoupled and after or during separating the uppermost inner tube from the adjacent second uppermost inner tube.

[0051] In a third aspect, the method may comprise providing a device as described above in relation to the first aspect of the invention, and the method may comprise operating one or more features of the device to carry out the steps of the method.

[0052] According to a fourth aspect there is provided a device for handling core samples during a core sample drilling operation, in use the core sample is received in a string of inner tubes within a drill string, the device comprising:

[0053] • an inner tube clamp;

[0054] • a core cutter and optionally a retainer device;

[0055] • a second rotation and optionally an associated slide unit;

[0056] • a core / lowermost innertube (CLI) capture device configured to receive the core / lowermost innertube in a controlled manner.

[0057] 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".

[0058] 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.

[0059] 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. 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.

[0060] Brief of the

[0061] An example embodiment of the invention is now discussed with reference to the Figures.

[0062] Fig 1 is a prior art schematic (not to scale) drawing of a typical core sample drilling rig;

[0063] Fig 2 is a schematic (not to scale) drawing of one example of an up-hole drilling; apparatus according to the present invention in a start position for receiving a lowermost inner tube;

[0064] Fig 3 is a schematic (not to scale) drawing of the present invention as shown in Figure 2 with the lowermost inner tube in an intermediate position during delivery to the core capture device; and

[0065] Fig 4 is a schematic (not to scale) drawing of the present invention as shown in Figure 3 with the lowermost inner tube fully delivered to the core capture device.

[0066] Best modes for carrying out the Invention

[0067] With respect to Figure 1 there is shown a typical prior art up-hole core drilling rig 100 which has a mast 1, a hollow drill rod 2 with a hollow drill bit 14 at the distal end of thereof. Inside the hollow drill rod 2 there is an inner tube 5 which collects core sample 6 therein.

[0068] The drill rig 100 is slidably connected to rotation and slide unit 4 which can hold and rotate the drill rods and which also has an linear actuator (not shown) which enables the unit 4 to be moved longitudinally with respect to the drill mast 1 as shown by double headed arrow X.

[0069] The drill rig 100 also has a foot clamp 3 for holding the drill rods

[0070] In operation the rotation device 4 and slide unit (not shown) can rotate the drill rods whilst the foot clamp 3 holds the in-ground rod to threadably add rods to, or remove rods from, the drill string. In relation to Figure 2 there is shown a core drilling rig 1000 substantially as described in relation to Figure 1 (except with the differences noted below) and which also has a core handling device 200 fitted thereto to enable for safe handling of a core sample 6 when undertaking up-hole core drilling. Like reference numerals have been used for the drill components shown in Figure 1.

[0071] The key difference of the present up-hole core drilling rig is that it is adapted for handling a string of two or more inner tubes as well as an individual drill rod noting the individual drill rod / inner tubes in the respective strings are not depicted in Figure 2.

[0072] The core handling device 200 has an inner tube clamp 7 which is situated on the drill mast in a position to hold a lowermost inner tube released from the drill rod. The core handling device also has a core cutter 8 adjacently positioned below the inner tube clamp 7.

[0073] The core cutter 8 is configured so that it can exist in a closed position after cutting a core sample to act as a retainer for holding the core sample in the string of inner tubes situated vertically above the cutter.

[0074] The core handling device 200 also has a rotation device 9 (or second rotation unit once mounted on the drill rig as shown) mounted on a slide unit (not shown) which is situated beneath the cutter 8 and longitudinally spaced distance which equates to around 70% the length of a inner tube (not shown) from the inner tube clamp 7. This separation between the inner tube clamp 7 and second rotation unit 9 enables the inner tube clamp 7 to grip the top portion of a lowermost inner tube in a drill string and the second rotation device 9 to grip the bottom portion of a lowermost inner tube.

[0075] The core handling device 200 also has a core / lowermost innertube (CLI) device in the form of a cylinder 11, plug 12 and vent 13 arrangement. In this particular example, of one preferred embodiment shown the plug has an external diameter having a close tolerance to the internal diameter of the cylinder 11. The cylinder 11 includes fluid therein which can only exit the cylinder 11 if forced under pressure to pass through vent 13.

[0076] It will be appreciated by those skilled in the art there are different ways to allow for a controlled descent of the inner tube and or core sample into the CLI - this could be by way of a spring - opposing magnets or allowing the plug to be undersized relative to the internal diameter (ID) of the LCI cylinder so the fluid can bypass the plug without needing to use the vent. The important aspect is that the core sample and or inner tube has a controlled descent into a CLI device.

[0077] In relation to the above and latter descriptions in relation to the Figures and other embodiments described in the specification, it should be appreciated that the core handling device 200 may be attached to and powered by the drill rig, i.e. hydraulic power may be provided by the rig.

[0078] The method aspect of the present invention can now be best further understood with reference to Figures 2, 3 and 4 showing one example thereof.

[0079] Figure 2 as described above shows the the core / lowermost innertube (CLI) device 400 in the form of a cylinder 11, plug 12 and vent 13 arrangement in the start position for retrieving a core sample with the lowermost inner tube.

[0080] As can be seen in Figure 2 the lowermost inner tube and core sample therein 300 has been fully or near fully released from the a core drilling apparatus for a string of drill rods / innertubes 100, (using gravity in a manner known within the industry and the lower end 301 of the lowermost inner tube / core sample therein 300 is then supported by plug 12 of the CLI device 400.

[0081] Figure 3 shows the lowermost inner tube / core sample therein 300 has now progressed its descent into the cylinder 12.

[0082] Figure 4 shows the lowermost inner tube / core sample now fully delivered to the cylinder and it is here the following method steps are performed: c) clamping lowermost end of the adjoining upper inner tube with inner tube clamp 7; d) rotating the lower inner tube - via second rotation device 9 - to unscrew it from the uppermost tube (or vice versa if rotation device 4 for the drill rods is configured to also clamp the smaller diameter inner tubes and the second rotation device 9 is used purely as a clamp) or rotating each inner tube in counter directions to one another via cooperations of rotation device 4 and second rotation device 9; e) sliding the lowermost tube relative to the adjacent upper most tube (or vice versa) using the an aforementioned slide unit or units - or the CLI via its acceptance of the lowermost inner tube relative to the adjacent upper inner tube which is held stationary by clamp 7, to expose a portion of the core sample; f) cutting the core sample with cutter 8 which is in the form of pair of opposed blades. Note it is important that the core cutter breaker - or some other retaining device (i.e. any mechanical arrangement which can prevent downward travel) is used at this stage to retain any remaining uphole core sample and or inner tube.

[0083] In the preferred method the core cutter / breaker device has 3 modes of operation (open, moving, and closed) at this stage the unit would be positioned in the closed mode preventing the inner tube and or core sample form falling. In the moving mode the cutter / breaker is cutting the core sample, and in the open mode the inner tube / core sample is free to pass by the cutter / breaker without interference.

[0084] The CLI device 400 is then moved so as to retrieve the lowermost inner tube and core sample therein from the drill rig 1000 in any suitable manner.

[0085] Benefits

[0086] 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 an 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.

[0087] It should also be noted that in addition to the productivity benefits, there are significant safety advantages offered by the device 1000 - both in terms of manual handling of the core samples, but also in the decreased frequency of manual handling of single inner tubes - compared to the mechanical handling of multiple inner tubes presented at a safe working height to the drill rig crew.

[0088] A key significant advantage of the present invention is the improved safety of the device in preventing the inner tubes or core sample becoming a potential spear which can use injury or death to workers operating the drill rig in an up-hole drilling operation. Another advantage of the present invention is the ability to increase the length of the single drilling rod from 3m to around 15m.

[0089] 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 core drilling rig adapted for up-hole (i.e. above vertical) drilling, which includes a core drilling apparatus for a string of drill rods / innertubes, comprising:• a drill mast;• a string of drill rods;• a string of inner tubes;• a drill bit on distal end of uppermost drill rod; a foot clamp which can hold the weight of drill rods and drill bit; and• a first rotation device and a slide unit; the first rotation device being capable of rotating and connecting / disconnecting (i.e., threading / unthreading) drill rods from the drill string as required with the assistance of the slide unit ; wherein the drill rig is characterized in that it further includes a handling device comprising:• an inner tube clamp;• a core cutter and optionally a retainer device; wherein once the core sample has been cut to release the lowermost section of the core sample, the core cutter or retaining device, is configured to retain any remaining uphole lengths of core sample and inner tubes with respect to the drill string;• a second rotation device and optionally an associated slide unit; and• a core / lowermost innertube (CLI) capture device configured to receive the core / lowermost innertube in a controlled manner.

2. A method of up-hole drilling for core samples utilising a string of at least two inner tubes and which provides a safe manner for retrieving core samples from said string of inner tubes, and separating said string at the drill rig , the method comprising the steps of: a) releasing the inner tubes from the drill string; b) receiving the lowermost inner tube in a capture device; c) clamping lowermost inner tube; d) rotating an adjacent upper inner tube relative to an adjacent lower inner tube (or vice versa) to detach the lower inner tube from the string of inner tubes, or rotating each inner tube in counter directions to one another to detach the lower inner tube from the sting of inner tubes; e) sliding the lowermost tube relative to the adjacent upper most tube (or vice versa), or sliding both of these inner tubes away from each other, to expose a portion of the core sample;f) cutting the core sample; g) retaining the balance of up-hole core sample(s) in the uppermost string of inner tubes; h) moving the capture device to allow for retrieval of core sample from drill rig; i) moving the capture device to be adjacent the lowermost inner tube; j) repeating steps a) to h) until the entire core sample has been retrieved from the drill rig at step f).

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