A coring drill tool for automatic impact and stuck pipe release when encountering stuck core during drill pipe hoisting

Abstract

The present invention discloses a core drilling tool for automatic impact and stuck pipe release during core extraction while pulling out the drill, which relates to the technical field of geological exploration. It includes an upper single-action suspension device, an automatic impact generating device, an inner core tube, and an outer drill pipe; the lower part of the upper single-action suspension device is connected to the automatic impact generating device and the outer drill pipe; the lower part of the automatic impact generating device is connected to the inner core tube; the outer drill pipe is sleeved outside the automatic impact generating device and the inner core tube, and there is a gap between the inner wall of the outer drill pipe and the outer walls of the automatic impact generating device and the inner core tube; the bottom end of the inner core tube is connected with a clamp seat by threads, and a clamp is arranged in the clamp seat; the bottom end of the outer drill pipe is connected with a drill bit by threads. The present invention works automatically when encountering a stuck core, generates an impact load to vibrate and release the stuck pipe until the stuck pipe is released and normal drilling is resumed, solves the problem of short footage per round trip when encountering a stuck core during core extraction while pulling out the drill, reduces the time consumed for pulling out the drill to clean the stuck material, and improves the operation efficiency of core extraction while pulling out the drill.

Description

Technical Field

[0001] The present invention relates to the technical field of geological exploration, and particularly to a core barrel for core drilling with automatic impact and stuck core release when encountering stuck core during core extraction by hoisting the drill Background Art

[0002] Core sampling is an important task in geological exploration and the only way to obtain original formation specimens. For small core sampling diameters and continuous core sampling, wireline core drilling technology is mostly used. For large core sampling diameters and non - continuous core sampling, core drilling by hoisting the drill is mostly used. Core drilling by hoisting the drill means that when core sampling is required, a core barrel is lowered. After the footage of the core barrel length of the core barrel is drilled, the drill is hoisted to obtain the core. A round - trip core sampling operation needs to go through three main work processes: lowering the drill - core drilling - hoisting the drill. In the round - trip core sampling operation, the auxiliary time such as lowering and hoisting the drill accounts for a relatively high proportion. Stuck core means that during the core sampling operation, the core is blocked in the core barrel, core clamp, etc., resulting in the inability of the lower core to smoothly enter the core barrel, causing phenomena such as core grinding and no footage. During the core drilling by hoisting the drill operation, when encountering loose and broken formations, the stuck core phenomenon often occurs, and the footage of a round - trip core drilling is much lower than the length of the core barrel of the core barrel. In today's core drilling by hoisting the drill operation, when encountering the stuck core situation, usually only by hoisting and pressing the drill and using static pressure to release the stuck; if the stuck cannot be released, then the drill needs to be pulled out for cleaning. Frequent tripping operations result in very low core sampling efficiency and very high construction costs. Therefore, a core barrel that can achieve core sampling without or with less drill pulling when encountering stuck core is particularly important in core drilling by hoisting the drill Summary of the Invention

[0003] The main purpose of the present invention is to provide a core barrel for core drilling with automatic impact and stuck core release when encountering stuck core during core extraction by hoisting the drill to solve the above problems

[0004] To achieve the above object, the present invention provides a core barrel for core drilling with automatic impact and stuck core release when encountering stuck core during core extraction by hoisting the drill, including an upper single - acting suspension device, an automatic impact generating device, an inner core tube, and an outer drill pipe; the lower part of the upper single - acting suspension device is connected to the automatic impact generating device and the outer drill pipe; the lower part of the automatic impact generating device is connected to the inner core tube; the outer drill pipe is sleeved outside the automatic impact generating device and the inner core tube, and there is a gap between the inner wall of the outer drill pipe and the outer walls of the automatic impact generating device and the inner core tube; the bottom end of the inner core tube is thread - connected with a clamp seat, and a clamp is arranged in the clamp seat; the bottom end of the outer drill pipe is thread - connected with a drill bit

[0005] Further, the upper suspension device includes a lock nut, a core pipe, a pressure bearing, a suspension nipple, and a bearing seat. The bottom of the suspension nipple is threadedly connected to the bearing seat. The pressure bearing is sleeved on the new pipe and fixed by the lock nut at the upper end of the core pipe. The core pipe is suspended inside the suspension nipple through the pressure bearing. The pressure bearing is an open bearing, allowing a small amount of drilling fluid to pass through, achieving the functions of lubrication and temperature reduction.

[0006] Further, the automatic impact generating device includes a reducing joint, an upper spring, a piston, an upper housing, a lower spring, a lower housing, a hammer, and an anvil seat. The reducing joint is a hollow structure, threadedly connected to the core pipe at the upper end and to the upper housing at the lower end. The top of the upper housing is evenly distributed with a plurality of slurry passing holes along the cylindrical surface. A hollow piston is installed inside the upper housing. There is an annular space between the upper part of the piston and the upper housing. An upper spring is installed in the annular space. The upper spring sits on the step surface of the protruding structure in the middle of the piston and contacts the lower end surface of the reducing joint at the upper end. Under normal circumstances, there is a gap between the piston and the reducing joint. When the core is blocked, the piston compresses the spring and moves upward, and the top end surface of the piston contacts the lower end of the reducing joint to block the slurry passing holes. The lower end of the piston is threadedly connected to the lower housing. A hammer is installed inside the lower housing. The hammer is a hollow structure, and the upper end of the hammer extends into the piston. There is an annular space between the upper part of the hammer and the lower housing. A lower spring is installed in the annular space. A disc-shaped space is provided at the lower end of the hammer. The lower end of the lower housing is threadedly connected to the anvil seat, and the hammer sits on the anvil seat. The lower end of the lower housing is evenly distributed with a plurality of drainage holes along the cylindrical surface. The drainage holes are located above the anvil seat. Under normal circumstances, the hammer blocks the drainage holes. When the core is blocked and the hammer compresses the spring and moves upward by a certain stroke, the drainage holes are exposed. An inner step is provided in the middle of the anvil seat. The inner step serves to hold the steel ball and form a one-way seal. The lower end of the anvil seat is threadedly connected to the core inner pipe.

[0007] Further, under normal circumstances, the automatic impact generating device of this drill tool does not work and is used in the same way as a conventional coring drill tool. When the core is blocked, the automatic impact generating device automatically works, generating a vibration load to release the stuck situation. After the blockage is released, the automatic impact generating device automatically stops working.

[0008] Further, two sets of centralizers are provided between the core inner pipe and the drill tool outer pipe. The centralizers are provided with holes for the passage of drilling fluid.

[0009] Further, a sealing steel ring is sleeved on the small-diameter section where the upper part of the hammer extends into the piston.

[0010] Furthermore, the core inner pipe is an inner-coated inner pipe.

[0011] The present invention has the following beneficial effects:

[0012] 1. When encountering a stuck core, the automatic impact generating device in the present invention automatically operates to generate impact loads and vibration to release the stuck situation until the stuck is released and normal drilling resumes. This solves the problem of short footage per run when the core barrel gets stuck during core drilling, reduces the large amount of time consumed in pulling out the drill to clean the stuck material, and greatly improves the efficiency of core drilling operations.

[0013] 2. During normal drilling, the present invention is no different from a conventional single-action double-tube core barrel for core drilling. The impact generating device does not operate and only starts to work automatically when a stuck core is encountered. On the one hand, it reduces the working time of the impact generating device and extends its service life underground, solving the problem of the relatively short service life of the hydraulic impact generating devices used in current drilling operations. On the other hand, under normal conditions, the impact generating device does not generate impact loads, reducing the impact on the core during the coring operation and facilitating the preservation of the integrity of the core.

[0014] 3. The pressure bearing in the upper suspension device of the present invention uses an open-type pressure bearing, allowing a small amount of drilling fluid to pass through to achieve the functions of lubrication and cooling, which is beneficial to extending the bearing life.

[0015] 4. The inner tube of the present invention uses an inner-coated inner tube. On the one hand, it can improve the strength of the inner wall of the inner tube, preventing scratches on the core blocks and thus avoiding hindrance to core entry. On the other hand, it improves the smoothness of the inner wall of the inner tube, which is beneficial to core entry.

[0016] 5. The core barrel structure of the present invention is simple and does not have high-precision sealing components, making it convenient for disassembly, installation, maintenance, and repair at the drilling construction site. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 is a structural diagram of a core barrel for core drilling with automatic impact and stuck release when encountering a stuck core according to the present invention.

[0018] Figure 2 is a schematic diagram of the normal working state of a core barrel for core drilling with automatic impact and stuck release when encountering a stuck core according to the present invention.

[0019] Figure 3a 、 Figure 3b 、 Figure 3c 、 Figure 3d is a schematic diagram of the automatic impact and stuck release working process of a core barrel for core drilling with automatic impact and stuck release when encountering a stuck core according to the present invention.

[0020] Figure 4 is a schematic diagram of the stuck release and return to normal working condition of a core barrel for core drilling with automatic impact and stuck release when encountering a stuck core according to the present invention.

[0021] Among them, 1 - locking nut; 2 - core pipe; 3 - pressure bearing; 4 - suspension sub; 5 - bearing seat; 6 - reducer joint; 7 - slurry passing hole; 8 - upper spring; 9 - piston; 10 - upper housing; 11 - sealing steel ring; 12 - lower spring; 13 - lower housing; 14 - impact hammer; 15 - flow discharge hole; 16 - steel ball; 17 - anvil seat; 18 - inner core tube; 19 - centralizer ring; 20 - drill pipe outer tube; 21 - clamp seat; 22 - drill bit. Detailed implementation mode

[0022] To achieve the above - mentioned purpose and effect, the technical means and structure adopted by the present invention will be described in detail for its features and functions in combination with the drawings in the preferred embodiment of the present invention.

[0023] As Figure 1 shown, the present invention provides a core - drilling tool for automatic impact and stuck - core release when pulling out the drill, which includes an upper single - acting suspension device, an automatic impact generating device, an inner core tube 18, and a drill pipe outer tube 20; the lower part of the upper single - acting suspension device is connected to the automatic impact generating device and the drill pipe outer tube 20; the lower part of the automatic impact generating device is connected to the inner core tube 18; the drill pipe outer tube 20 is sleeved outside the automatic impact generating device and the inner core tube 18, and there is a gap between the inner wall of the drill pipe outer tube 20 and the outer walls of the automatic impact generating device and the inner core tube 18; the bottom end of the inner core tube 18 is connected with a clamp seat 21 by thread, and a clamp is arranged in the clamp seat; the bottom end of the drill pipe outer tube 20 is connected with a drill bit 22 by thread.

[0024] The upper suspension device includes a locking nut 1, a core pipe 2, a pressure bearing 3, a suspension sub 4, and a bearing seat 5; the bearing seat 5 is screwed at the bottom of the suspension sub 4; the pressure bearing 3 is sleeved outside the core pipe 2, and the pressure bearing 3 is fixed on the core pipe 2 by the locking nut 1; the pressure bearing 3 is seated on the bearing seat 5 to suspend the core pipe inside the suspension sub; the pressure bearing 3 is an open - type bearing, allowing a small amount of drilling fluid to pass through to achieve the functions of lubrication and temperature reduction.

[0025] The automatic impact generating device includes a reducing joint 6, an upper spring 8, a piston 9, an upper housing 10, a lower spring 12, a lower housing 13, a hammer 14, a steel ball 16, and an anvil 17. The reducing joint 6 has a hollow structure, with its upper end connected to the core pipe 2 by threads and its lower end connected to the upper housing 10 by threads. Six slurry holes 7 are evenly distributed along the cylindrical surface at the top of the upper housing 10. A hollow piston 9 is installed inside the upper housing 10. There is an annular space between the upper part of the piston 9 and the upper housing 10, and the upper spring 8 is installed in the annular space. The upper spring 8 sits on the upper step surface of the protruding structure in the middle of the piston 9, and its top contacts the lower end surface of the reducing joint 6. There is a gap between the piston 9 and the reducing joint 6. The lower end of the piston 9 is connected to the lower housing 13 by threads. The hammer 14 is installed inside the lower housing 13. The hammer 14 has a hollow structure, and the upper end of the hammer 14 extends into the piston 9. There is an annular space between the upper part of the hammer 14 and the lower housing 13, and the lower spring 12 is installed in the annular space. The lower spring 12 sits on the step surface of the hammer, and its top contacts the lower end surface of the top of the lower housing 13. A disc-shaped space is provided at the lower end of the hammer 14. The lower end of the lower housing 13 is connected to the anvil 17 by threads, and the hammer 14 sits on the anvil 17. Six drain holes 15 are evenly distributed along the cylindrical surface at the lower end of the lower housing 13. The drain holes are located above the anvil 17. There is a step in the inner cavity of the anvil 17. The inner cavity step can hold the steel ball 16 to form a one-way seal. The lower end of the anvil 17 is connected to the core inner tube 18 by threads. When there is no plugging of the core, the drilling fluid flows through the inner cavity of the core pipe 2 and the slurry holes 7 into the gap between the core inner tube 18 and the drill string outer tube 20 to participate in the circulation. The piston 9 and the hammer 14 are always in the low position and in a relatively static state. When the impact condition is reached, the piston 9 moves upward to block the slurry holes 7, forming a high pressure in the inner cavity. The hammer 14 moves upward under the pressure of the drilling fluid. After the drain holes 15 are depressurized, the hammer 14 moves downward under its own weight and the action of the lower spring 12 to impact the anvil 17, generating impact energy. When impacting the anvil, the drain holes 15 are blocked again, and the drilling fluid pressure pushes the hammer upward again. Such reciprocating motion continues until the blockage is removed and the core inner tube 18 drives the upper structure to drop until the slurry holes 7 are exposed.

[0026] In another embodiment, two sets of centralizers 19 are provided between the core inner tube 18 and the drill string outer tube 20 to ensure the centering and stability of the core inner tube. The centralizers 19 are provided with holes for the drilling fluid to pass through, facilitating the passage of the drilling fluid.

[0027] In another embodiment, a sealing steel ring 11 is sleeved on the small-diameter section where the upper part of the hammer 14 extends into the piston 9 to improve the sealing effect and prevent the leakage of the drilling fluid.

[0028] In another embodiment, the core inner tube 18 is an inner-coated inner tube. On the one hand, it can improve the strength of the inner wall of the inner tube, prevent scratches on the core blocks and cause blockage of the core entry; on the other hand, it improves the smoothness of the inner wall of the inner tube, which is beneficial to the core entry.

[0029] Assembly instructions for the coring tool

[0030] Assembly of the upper single-action suspension device: First, tightly screw the male thread of the bearing seat 5 with the female thread at the lower end of the suspension nipple 4. Then, fit the pressure bearing 3 onto the upper part of the core tube 2 from top to bottom and lock it with the lock nut 1. Finally, pass the core tube 2 and the pressure bearing 3 assembly through the suspension nipple from top to bottom. The core tube 2 is suspended in the suspension nipple 4 through the pressure bearing 3, and its upward movement is restricted by the contact between the end face of the small head of the male thread of the upper conventional drill tool and the upper end face of the core tube 2.

[0031] Assembly of the automatic impact generating device: First, fit the piston 9 into the upper housing 10 from top to bottom. Place the upper spring 8 in the annular gap between the piston 9 and the upper housing 10, and tightly screw the male thread at the lower end of the reducing joint 6 with the female thread at the upper end of the upper housing 10. Then, invert the lower housing 13, place the lower spring 12 into the inner cavity of the lower housing 13, put a sealing steel ring on the small-diameter section of the impact hammer 14, and place the impact hammer 14 into the lower housing 13 to ensure that the small-diameter section of the impact hammer 14 passes through the lower spring. Connect the male thread at the upper part of the anvil seat 17 with the female thread at the lower end of the lower housing 13. Finally, fit the lower end of the piston 9 onto the upper end of the impact hammer 14 and tightly screw the male thread at the lower end of the piston 9 with the female thread at the upper end of the lower housing 13 to complete the assembly of the automatic impact generating device.

[0032] Assembly of the coring tool: First, tightly screw the male thread of the core tube 2 exposed at the bottom of the upper single-action suspension device with the female thread of the reducing joint 6 at the top of the automatic impact generating device. Then, place a clamp in the clamp seat 21 and screw the clamp seat 21 onto the bottom of the core inner tube 18. Connect the female thread at the top of the core inner tube 18 with the male thread at the lower part of the anvil seat 17 and tightly screw the connection threads of the anvil seat 17 with the lower housing 13 and the core inner tube 18. Finally, put a centralizer 19 on the core inner tube 18, put the assembled upper single-action suspension device, automatic impact generating device and the core inner tube 18 string into the drill pipe outer tube 20, and tightly screw the male thread at the bottom of the suspension nipple 4 with the female thread at the top of the drill pipe outer tube 20 to complete the assembly of the entire coring tool.

[0033] Instructions for use and working state

[0034] When coring is required, first tighten the male buckle of the drill bit 22 with the female buckle at the bottom end of the drill tool outer tube 20, and adjust the distance between the bottom end face of the clamp seat 21 and the inner step of the drill bit 22; then connect the upper part of the coring drill tool to the conventional drill tool, and limit its upward movement by contacting the small end face of the male buckle of the upper conventional drill tool with the upper end face of the core tube; finally, lower the coring drill tool to the bottom of the hole through the conventional drill tool. After the coring drill tool is lowered to the bottom of the hole, first use a large displacement to flush the inner tube and the sediment at the bottom of the hole, and adjust the drilling fluid performance in a cycle. When there is no sediment at the bottom of the hole and the drilling fluid performance meets the requirements, stop the pump and remove the active drill rod, and put the steel ball 16 into the drill tool, so that the steel ball 16 falls on the step hole of the anvil 17, blocking the drilling fluid from flowing through the core inner tube 18, and then start normal coring drilling.

[0035] Under normal circumstances (when the core is not blocked), the coring drill goes down with the drill bit, and the core goes up relative to the drill and enters the core inner tube 18. The drilling fluid flows through the inner cavity of the core tube 2 and the slurry hole 7 into the gap between the core inner tube 18 and the drill outer tube 20 to participate in the circulation. Figure 2 shown.

[0036] When the core is blocked, the gap between the core and the clamp is blocked by the broken rock, and the core cannot enter the core inner tube 18 and presses against the core inner tube 18. At this time, the drill bit outer tube 20 is still moving downward, and the core inner tube 18 drives the piston 9 to move upward and compress the upper spring 8 until the upper end surface of the piston 9 contacts the lower end surface of the reducer 6 to seal the slurry hole 7, and the circulation is interrupted. Figure 3a After the slurry hole 7 is sealed, the drilling fluid pressure in the inner cavity of the drill tool increases, and the drilling fluid pressurizes the disc-shaped space at the bottom of the hammer 14, pushing the hammer 14 upward, compressing the lower spring 12 to store energy, such as Figure 3b As shown; the hammer 14 moves upward to the leakage hole 15, the drilling fluid flows out from the leakage hole 15 to release the pressure, and the hammer 14 moves downward under the release of energy from the lower spring 12 and its own gravity, as shown Figure 3c As shown; the hammer 14 releases the energy of the lower spring 12 and its own gravity, and then it goes down to hammer the anvil 17 to generate an impact load. The impact load is transmitted to the plugging point through the core inner tube 18. At the same time, the leakage hole 15 is sealed by the hammer, and the drilling fluid pressure in the drilling tool cavity increases. Under the action of the drilling fluid, the hammer repeats the action of "upward compression spring-pressure relief downward impact anvil", and the generated impact load is continuously transmitted to the plugging point through the core inner tube 18. The plugging object is loosened and released through continuous hammering and vibration, as shown in FIG. Figure 3d shown.

[0037] After the blockage is released, the core enters the core inner tube 18, and no longer blocks the downward movement of the core inner tube 18. The downward movement of the core inner tube 18 drives the upper piston downward, and the slurry hole 7 is exposed, and normal circulation drilling is resumed. Figure 4 shown.

[0038] The above are only the preferred embodiments of the present invention, not all embodiments. Anyone should know that structural changes made under the inspiration of the present invention, as long as they have the same or similar technical solutions as the present invention, all fall within the protection scope of the present invention.

Claims

1. An automatic impact stuck-core releasing coring drill tool for core lifting and coring, characterized in that, it includes an upper single-action suspension device, an automatic impact generating device, a core inner tube and a drill tool outer tube; the lower part of the upper single-action suspension device is connected to the automatic impact generating device and the drill tool outer tube; the lower part of the automatic impact generating device is connected to the core inner tube; the drill tool outer tube is sleeved outside the automatic impact generating device and the core inner tube, and there is a gap between the inner wall of the drill tool outer tube and the outer walls of the automatic impact generating device and the core inner tube; the bottom end of the core inner tube is connected with a clamp seat by threads, and a clamp is arranged in the clamp seat; the bottom end of the drill tool outer tube is connected with a drill bit by threads. The upper single-action suspension device includes a locking nut, a core tube, a pressure bearing, a suspension nipple and a bearing seat; a bearing seat is arranged inside the bottom end of the suspension nipple; a pressure bearing is sleeved outside the core tube, and a locking nut is arranged at the upper end of the core tube to fix the pressure bearing on the core tube; the core tube is suspended inside the suspension nipple through the pressure bearing to achieve the effect that the outer tube rotates and the inside does not rotate; the pressure bearing is an open-type bearing, allowing a small amount of drilling fluid to pass through to achieve the function of lubrication and cooling. The automatic impact generating device includes a reduced-diameter joint, an upper spring, a piston, an upper housing, a lower spring, a lower housing, a hammer and an anvil seat; the reduced-diameter joint is a hollow structure, the upper end is connected to the core tube by threads, and the lower end is connected to the upper housing by threads. A plurality of slurry passing holes are evenly distributed along the cylindrical surface at the top of the upper housing; a hollow piston is installed inside the upper housing, and there is an annular space between the upper part of the piston and the upper housing; the upper spring is installed in the annular space between the upper part of the piston and the upper housing, and the lower end of the upper spring sits on the stepped surface of the protruding structure in the middle of the piston, and the upper end contacts the lower end surface of the reduced-diameter joint; normally, there is a gap between the piston and the reduced-diameter joint to ensure normal slurry passing through the slurry passing holes. When the core is blocked, the piston compresses the spring and moves upward, and the top end surface of the piston contacts the lower end surface of the reduced-diameter joint to block the slurry passing holes; the upper section of the lower housing is connected to the lower end of the piston by threads, and a hammer is installed inside the lower housing; the hammer is a hollow structure, the upper end of the hammer extends into the piston and forms a sealed fit with the inner cavity of the piston; there is an annular space between the upper part of the hammer and the lower housing, and the lower spring is installed in the annular space between the upper part of the hammer and the lower housing. The lower end surface of the lower spring sits on the stepped surface of the hammer, and the upper end surface contacts the lower surface of the inner cavity at the top of the lower housing; the hammer sits on the anvil seat, and a disc-shaped space is arranged at the lower end of the hammer, and the whole lower end surface does not contact the anvil seat; the lower end of the lower housing is connected with an anvil seat, and a plurality of drain holes are evenly distributed along the cylindrical surface at the lower end of the lower housing; the drain holes are located above the anvil seat. Normally, the drain holes are blocked by the hammer. When the hammer compresses the spring and moves upward a certain distance when the core is blocked, the drain holes are exposed; a stepped hole is arranged inside the anvil seat, and the stepped hole inside the anvil seat plays a role in holding the steel ball to form a one-way seal. The lower end of the anvil seat is connected to the core inner tube.

2. An automatic impact stuck-core releasing coring drill tool for core lifting and coring according to claim 1, characterized in that, Under normal circumstances, the automatic impact generating device of this drill tool does not work and is used in the same way as a conventional coring drill tool. When the core is blocked, the automatic impact generating device works automatically to generate a vibration load for releasing the stuck situation, and it automatically stops working after the blockage is released.

3. A coring drill tool with automatic impact and stuck core release for core extraction while pulling out the drill, as described in claim 1, characterized in that, two groups of centralizers are provided between the core inner tube and the drill tool outer tube, and holes for drilling fluid to pass through are provided on the centralizers.

4. A coring drill tool with automatic impact and stuck core release for core extraction while pulling out the drill, as described in claim 1, characterized in that, a sealing steel ring is sleeved on the small-diameter section where the upper part of the impact hammer extends into the piston.

5. A coring drill tool with automatic impact and stuck core release for core extraction while pulling out the drill, as described in any one of claims 1-4, characterized in that, the core inner tube is an inner-coated inner tube, which plays a role in increasing the hardness and smoothness of the inner wall of the inner tube, and prevents the core from scratching the inside of the inner tube and causing blockage.

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