DRY DRILLING AND CORE ACQUISITION SYSTEM
A rotary dry drilling system comprises a surface mounted drill having a drill bit and a drill bit driver rotationally connected by a hollow drill string. There is included core sample capture means adapted to travel from the head of the drill string to the tail of the drill string. The system also comprises an auger for removing cuttings from a comminution zone and cuttings fluidization means to facilitate transport of cuttings from the comminution zone to the auger. Once the cuttings are removed by the auger they are collected and transported to the surface for disposal.
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The present application is a continuation-in-part of our U.S. patent application Ser. No. 11/746,626 filed in the USPTO on May 9, 2007.
FEDERAL FUNDINGN/A.
FIELD OF THE INVENTIONThe present invention relates generally to the field of core boring and more particularly to a dry drilling and core capture device.
BACKGROUND OF THE INVENTIONTraditional sample recovery systems rely heavily upon the use of water to flush the cuttings away from the rock/bit interface or comminution zone. Water pressure is also used to deliver the core capture device to the bottom of the hole and allows the dogging mechanism to latch properly. This technology only works on consolidated material. Unconsolidated materials would normally be flushed away from the hole thus preventing the capture of a sample.
Lunar drilling will be a dry drill scenario. Fluids will not likely be available to flush away the cuttings from the comminution zone. Additionally, there is a desire to capture unconsolidated material rather than flush it away. Thus conventional drilling cannot be used.
There is a need for an apparatus that permits dry drilling and core capture in environments where fluid will not likely be available.
SUMMARY OF THE INVENTIONThe apparatus of this invention is designed for dry drilling and core capture and so solves the need stated above. The apparatus is a rotary dry drilling system comprising a surface mounted drill having a drill bit and drill bit driving means rotationally connected through a hollow drill string to the drill bit for drilling a bore through rock to obtain a core sample of the rock. The drill string has a head and a tail. The core sampler is adapted to travel from the head of the drill string to the tail of the drill string through the hollow drill string to capture the core sample of rock. There is also included auger means connected to the drill bit for removing cuttings from the drill comminution zone and transporting the cuttings up-hole. To ensure that the cuttings move smoothly up-hole and do not foul the drilling operation there is provided with the system a cuttings fluidization means connected to the head of the drill string to facilitate transport of cuttings from the comminution zone to the auger means. A cuttings management means is connected to the drill string for collecting and transporting cuttings to the surface. The core sampler or core capture device comprises a rotating gate assembly having a first open position and a second closed position; a core tube adapted to receive a core sample; an activation tube coaxial with the core tube and surrounding the core tube. The activation tube is adapted to mechanically engage the rotating gate assembly thereby moving it from the first open position to the second closed position. A screw cap is included and adapted to engage the activation tube and transmit rotational movement from the drill motor to the activation tube so that the activation tube is forced into engagement with the gate assembly. The gate assembly comprises a gate assembly housing fixed to the bottom end of the core tube to house a rotating gate body. The rotating gate body comprises a first disc and a second disc. Each of the discs has an axis and they are co-axial. The first disc and second disc are jointed by a member between the respective rims of the first and second disc.
The invention is more fully understood by referring to the following diagrams and detailed description.
The core capture device includes a core capture scoop (20) located at the down-hole end of the core capture tube (12). The scoop is adapted to capture a sample of a drill core (24) formed as the drill bit (18) progresses downward into a rock formation (22). As the core grows longer, it moves into the orifice (25) of the drill string and into the core capture device (20). Sensors on the drill string are able to measure just how much core is available for capture and when the core capture device should be activated.
The wire line mechanism (200) is an integral part of the entire sample capture device. The wireline delivers the sample capture device to the bottom of the hole and it activates the opening and closing of the sampling scoop. Once the sample capture device is in place, operational sequences allow the wireline to move from controlling the opening and closing of the scoop to opening and closing of the bailings bucket port. Once these operations are complete, the wireline disengages, by means of a clutch mechanism, and allows the sampling device and port opening to rotate freely with the drill string while the wireline stays stationary.
As the drill completes a drilling cycle (has drilled a sample), the wireline re-engages and closes off the bailings bucket ports, thus preventing any loose material entering the inside of the drill string. Following port closure, the wireline re-positions itself to facilitate the closure of the gate on the sample capture device, thus capturing the sample. The sample capturing device is capable of capturing a sample of consolidated or unconsolidated material.
Once the sample has been secured, the wireline hoists the entire bailings bucket and sample capture device mechanism to surface, where the captured sample or cuttings from the bailings bucket may be further processed or disposed of as required.
The wire line is required to:
(1) impart thrust to facilitate the collapse of the spring activated components;
(2) be capable of handling the retraction forces required to break a consolidated sample, release the springs and to lift the core capture device up the drill string;
(3) be flexible enough to allow the wireline to be coiled on surface during retrieval and stowed sequences; and,
(4) be rigid to allow rotational forces to be transmitted when in the extended locked position.
The wireline configuration has a first retracted position and a second deployed position. In its retracted position, the wireline can be coiled onto a spool where it awaits deployment. Once activated, the wireline is pulled off the spool into a deployed position down the drill string. Once the core capture device has contacted the bottom of the hole, the wireline is mechanically locked together by a pin system illustrated herein.
Referring to
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In operation, active port control is incorporated in the upper section of the auger mechanism and is in the transition zone. Cuttings from the comminution zone migrate to the top portion of the auger with the aid of the fluidizer which is more fully described below. The outer diameter of the port control mechanism above the auger is larger, thereby directing the cuttings into and through the ports to fall into the bucket for transport to the surface. The activation of the port control is completed via the wireline mechanism. During a drilling sequence, the ports are open allowing the cuttings to pass through the port into the bailings bucket. During a bailings bucket extraction cycle, the ports are closed prior to removing the core sampling device and bailings bucket, thus preventing the ingress of contaminants onto the seating area of the sample capture device.
Contaminants at the bottom of the hole would prevent the sample capture device from seating properly once it had returned from surface for the next drilling cycle.
Referring now to
To capture a sample using the core capture device, the following procedure would be used. The wireline (200) would be forced down vertically until the swivel clutch assembly (204) was engaged. The wireline (200) would then be rotated in a counter clock wise (CCW) direction to close off the port control sleeve (292). When the port is closed off, the wireline (200) would be forced down vertically until the dog clutch (285) enter the port control sleeve (292) undercut. The wireline (200) would then continue to rotate in a CCW direction until the dogs clutch (285) retracted and the scoop is close off. When the scoop is closed off, the sampling device, bailings bucket, port control and swivel line can then be removed from the drill string.
Cuttings Disposal and the Bailings BucketReferring to
Referring to
The sample capture device (10) is connected below the bottom nut (304) so that the bottom section of the bailings bucket is the transition zone between the bucket and sample capture device. The bailings bucket transmits the forces of the wireline directly to the sample capture device for operation of the scoop allowing a sample to be captured.
In
An operating sequence is outlined below for capturing an unconsolidated sample.
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- Position the core capture device gate in an open position while drilling, allowing the sample to enter into the core capture device.
- Permit the sample to fill the core capture tube as indicated by the drill's penetration sensor.
- Push the wireline into a closed position (collapsed) to transfer rotational forces to the core capture device gate.
- Rotate the drill string to drive the outer activation tube down over the sample tube.
- Rotate the core capture device gate 90 degrees into the closed position, closing off the bottom opening and capturing the sample.
- Use the wireline to draw the core capture device, sample and bailings bucket to surface.
The operating sequence for capturing a consolidated (core) sample is outlined below.
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- Open the core capture device gate to permit the sample to enter the core capture tube.
- Fill the sample tube as indicated by the drill's penetration sensor.
- Push the wireline into the closed position (collapsed) to transfer rotational forces to the gate.
- Rotate the head clamp of the drill string to drive the outer activation tube down over the sample tube.
- Commence to close the core capture device gate until the predetermined forces are exerted on the gate due to its closure on a core. Torque sensing is used to ensure that the core capture device is not damaged if it cannot fully close.
- Permit the core capture device to rotate freely around the core so that the base of the core is scored by the gate.
- Stop the rotation and close the gate in order to snap the core from the rock base.
- Commence to close the core capture device gate until the predetermined forces are exerted on the gate due to its closure on a core. Torque sensing is used to ensure that the core capture device is not damaged if it cannot fully close.
- This cycle continues until the gate is fully closed and the core sample is freed from its base rock.
- Once the gate is fully closed, the wireline is used to draw the core capture device, core sample and bailings bucket to surface.
In experimentation with the core capture device described above, it quickly became evident that as the auger tube became surrounded by the drill cuttings, the ability for the auger to continue to move the cuttings up the flights decreased. The auger no longer effectively transported the cuttings to the cuttings bucket efficiently and tended to pack the cuttings within the flights of the auger. As a result, drill penetration rates dropped significantly. As well, the reaction forces within the device started to climb and there was notable heat generation in the auger zone. A further result of cuttings removal degradation was balling of material on the bit rendering it ineffective.
To prevent bit balling and clumping at the bottom of the drill hole, it was decided that a cuttings fluidization technique was needed. Test results of the fluidizer described herein indicated that it increased the rate of drill penetration by maintaining the cuttings in a fluid state so that the auger could easily remove the cuttings from communition zone to the bailings bucket.
The fluidizer works by transmitting an impact through the drilling device at a specific frequency. A key requirement for the fluidizer was a direct variable frequency impacting device, capable of delivering a blow that would reverberate through the entire length of the drill string to the comminution zone. Previous tests eliminated such concepts as pinging the side of the drill string or having an electric impact drill incorporated into the top of the drill. Additionally, the frequency of the impacts has to be variable, separate and not necessarily proportional to the rotational speed of the drill string. Drilling through several types of test media required different rotational speeds to move the cuttings from the comminution zone to the augers on the bit and up onto the flights of the auger. If the rotational speed combined with the impacts of the fluidizer is insufficient, the cuttings would begin to pack, and render the auger inefficient. The requirement was an electro-mechanical fluidizer capable of providing a significant impact to the drill string without affecting the other drilling components.
(A) and side view (B). The housing has the shape of a cylindrical dish consisting of a wall (506) and a bottom surface (508). The aperture (510) in the middle of the bottom surface is adapted to permit passage of the drill string and to mount the anvil/hammer assembly. A first plurality of apertures (570) is adapted to mount the hammer mounts. A second plurality of apertures (572) is adapted to mount the cam mounts. A third plurality of apertures (574) is adapted to mount the flat top plate (504) to the top of the housing. A fourth plurality of apertures (575) is adapted to mount the bottom housing to the drill frame so that percussions from the anvil and hammer travel down the drill string. Dimensions shown on
FIG. 20,illustrates the flat top cap (504) in a top view (A) and side view (B). The cap is circular having a large first aperture (580) adapted to permit the drill sting passage through the top cap. A second aperture (582) permits passage of the motor shaft and a third aperture (584) permits passage of the spring into the spring housing. A first set of small apertures (586) mounts the motor assembly to the top surface of the top plate, a second set of small apertures (588) mounts the spring housing to the top surface of the top plate and a third set of small apertures (590) mounts the top plate to the housing. The bottom surface (592) of the top plate comprises a flange (594) that seats within the housing wall and provides a tight seal to the housing to prevent dust ingress into the housing.
Although the description above contains much specificity, these should not be construed as limiting the scope of the invention but as merely providing illustrations of some of the presently preferred embodiments of this invention. Thus the scope of the invention should be determined by the appended claims and their legal equivalents.
Claims
1. A rotary dry drilling system comprising:
- a. a surface mounted drill having a drill bit having a comminution zone and drill bit driving means rotationally connected through a hollow drill string to said drill bit for drilling a bore through rock to obtain a core sample, wherein said drill string has a head and a tail;
- b. a core sample capture device disposed within a core capture tube proximate to the tail of the drill string, said core capture tube disposed within an activation tube for transmitting activating and deactivating forces to the core capture device by means of a wire line; said core capture device comprising: i. a rotating scoop assembly having a first open position and a second closed position; ii. a core tube adapted to receive a core sample; iii. wherein, the activation tube is coaxial with said core tube and surrounds the core tube; iv. and wherein, the activation tube is adapted to mechanically engage said rotating scoop assembly thereby moving it from said first open position to said second closed position; and, v. the core capture tube further comprising a screw cap adapted to engage the activation tube and transmit rotational movement from the drill motor to the activation tube so that the activation tube is forced into engagement with the scoop assembly;
- c. an auger tube disposed around the activation tube and above the drill bit, for removing cuttings from said comminution zone;
- d. a cuttings fluidization apparatus connected to said head of the drill string to facilitate transport of cuttings from the comminution zone to said auger tube; and,
- e. cuttings management means connected to said drill string for collecting and transporting cuttings to the surface.
2. The device as claimed in claim 1 wherein the scoop assembly comprises a lower housing fixed to the bottom end of the core tube, said lower housing adapted to house a rotating scoop member.
3. The device as claimed in claim 2 wherein said rotating scoop member comprises a first disc and a second disc, wherein:
- a. said first and second discs each have an axis;
- b. the first and second discs are co-axial and joined by a joining member between the respective rims of the first and second discs;
- c. the respective outside surfaces of the first and second discs each have fixed thereto a first lug and a second lug;
- d. said first lug is mounted between the respective axis of each disc of the first and second discs and the respective rim of each disc of the first and second discs; and,
- e. said second lug is mounted to the axis of each of the first and second discs.
4. The device as claimed in claim 3 wherein said lower housing includes a bottom orifice to accommodate said drill string, a left side orifice and a right side orifice wherein said left and right side orifices are opposite each other, and wherein the gate assembly housing receives said gate body.
5. The device as claimed in claim 4 wherein said gate assembly housing further comprises:
- a. a first mounting plate fixed over the left orifice;
- b. a second mounting plate fixed over the right orifice;
- c. wherein said first and second mounting plates each further include a central aperture for receiving the first and second disc first lugs permitting rotational movement of the gate body about its axis; and,
- d. wherein the first and second mounting plates respectively further include a first and second arcuate slots for receiving the first and second disc second lugs for guiding the gate body from a first open position to a second closed position.
6. The device in claim 5 wherein the joining member cuts the core sample when the gate body is moving from the first open position to the second closed position and encloses the core within the core tube.
7. The system as claimed in claim 1 wherein said cuttings fluidization apparatus comprises a shock wave transmitter for transmitting a shock wave from the top of the head of the drill string to the tail of the drill string.
8. The system as claimed in claim 7 wherein said shock wave transmitter comprises a housing mounted proximate to the head of the drill string by an aperture through which the drill string passes, wherein said housing comprises a casing having a removeably fixed casing cap for sealing said casing and an inside bottom surface.
9. The system as claimed in claim 8 wherein the casing is adapted to contain a flapper having a pinned end and a cam end, wherein said pinned end is pivotally pinned to said inside bottom of the casing and wherein said cam end is adapted for cycling up and down at a variable frequency so that on the down stroke said flapper strikes said inside bottom surface of the casing thereby sending a shock wave down the length of the drill string.
10. The system as claimed in claim 9 wherein said cam end of the flapper communicates with a cam, wherein said cam rotates on an axis and communicates said up and down cycling motion to the flapper cam end.
11. The system as claimed in claim 10, wherein the cam is connected to a variable speed motor for driving the cam rotationally about said axis, and wherein said variable frequency of flapper movement is regulated by regulating the speed of the motor, and wherein the cam end of the flapper is spring biased against the cam.
12. The system as claimed in claim 11 wherein the flapper is weighted to provide a correct magnitude of shock wave to the drill string.
13. The system as claimed in claim 12 wherein the shock wave travels to the tail of the drill string and is transmitted to the auger tube and the drill bit causing the vibration thereof and resulting in the fluidization of the cuttings so that they do not clump, ball, clump or bind to the drill bit or auger tube.
14. The system as claimed in claim 1 wherein said cuttings management means comprises:
- a. a bucket for collecting cuttings from the auger tube and transporting the cuttings to the head of the drill string;
- b. a port for directing cuttings from the auger tube to the bucket wherein said port has an open position and a closed position;
- c. port control means for moving the port from said open position to said closed position and from the closed position to the open position.
15. The system as claimed in claim 14 wherein said port control means comprises a tube section incorporated into the upper section of the auger tube, wherein said tube section includes a first and a second port oppositely disposed proximate to the bottom of the tube section.
16. The system as claimed in claim 15 wherein the bottom end of the tube section sits over the top end of the auger tube so that as cuttings are carried up the auger tube they are forced through the open ports and into said bucket.
17. The system as claimed in claim 16 wherein the ports are closed by said port control means so that the bucket can be removed from the bore hole and so that cuttings do not fall into the centre of the bore.
18. The system as claimed in claim 17 wherein port control means comprises a wireline mechanism having a first deployed configuration and a second stored configuration.
19. The system as claimed in claim 18 wherein said first deployed position said wireline is adapted to engage the sample capture device and position it in its open position.
Type: Application
Filed: Oct 30, 2010
Publication Date: Nov 3, 2011
Applicant: NORTHERN CENTRE FOR ADVANCED TECHNOLOGY INC. (Sudbury)
Inventors: Marcel VIEL (Sudbury), William Joseph SOREL (Sudbury), James Thomas ATWELL (Sudbury), Richard MOUSSEAU (Sudbury), Dale BOUCHER (Sudbury), David Roberts (Sudbury)
Application Number: 12/916,518
International Classification: E21B 25/16 (20060101);