Device and method for keeping straightness of ice rock interface under deep ice in Antarctic pole by coring and drilling
By designing a hollow tubular structure direct-in-rock rock device at the interface of deep subicles of Antarctic ice, the problem of failure of traditional drilling tools anti-inclination technology is solved, and the success of vertical infiltration and subic bedrock centering of the drill bit is achieved, and the device is prevented from being stuck during drilling.
Patent Information
- Application Number
- CN202411786645.2
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-12-06
- Publication Date
- 2025-02-28
AI Technical Summary
At the interface of deep under-ice ice rocks in Antarctica, traditional drilling tool anti-absorption technology fails, resulting in a skew of the drill bit and making it difficult to enter the rock vertically, affecting the success of the base rock centering under-ice bedrock.
A centralized drilling and straightening device for the interface of deep ice rocks in Antarctic deep ice rock was designed, and a straightening and straightening device with a hollow tubular structure was designed. It was connected to the external thread of the drill rod through internal threads, combining the caliper teeth and the cutting teeth of the top hole wall to achieve lateral constraints and vertical free movement of the drill bit.
This device can effectively restrict the lateral displacement of the drill rod and the drill bit, ensure the vertical entry of the drill bit into the rock at the interface of the ice rock, improve the success rate of the base rock centering under the ice rock, and prevent the device from being stuck due to the shrinkage of the ice hole during the drilling process.
Smart Images
Figure CN119531759A_ABST
Abstract
Description
Technical Field
[0001] The invention relates to the field of geological drilling technology, and in particular to a device and method for maintaining straightness in coring and drilling at an ice-rock interface under deep Antarctic ice. Background Art
[0002] The Antarctic environment is harsh, and the time available for scientific researchers to conduct drilling is short each year. To obtain the core of the bedrock under the ice, it is extremely difficult to penetrate the ice sheet that is hundreds or even thousands of meters thick. At present, the maximum length of the bedrock core under the ice obtained in Antarctica internationally does not exceed 8 meters.
[0003] During the deep-ice bedrock coring process, it is necessary to drill through hundreds of meters or even kilometers of ice before reaching the rock layer. After drilling through the ice layer, it is necessary to replace the drill bit with a smaller diameter to drill and coring the bedrock. This is to reduce the drilling torque required during the coring process. In addition, the interface between the ice layer and the bedrock is likely to be tilted. At the same time, the physical and mechanical properties of the ice layer and the rock layer are very different, resulting in a large deflection force on the drill bit. In order to make it easier to drill bedrock cores, the outer diameter of the coring drill bit is smaller than the borehole diameter of the overlying ice layer. The larger borehole diameter of the ice layer gives the drill rod a larger deformation space. If a large tilted ice-rock interface is encountered during drilling, it is easy for the hole to tilt, and even lead to coring failure.
[0004] The drill tool deflection prevention is achieved by changing the structure of the drill tool. At present, there are many drill tool deflection prevention technologies at home and abroad. Among them, the pendulum method is to add a stabilizer at the appropriate position of the drill tool, and resist the deflection of the drill tool through the pendulum force generated by the hollow drill tool under the stabilizer; the full-eye drilling deflection prevention technology prevents deflection by reducing the gap between the drill tool and the borehole, improving the rigidity of the drill tool and the supporting role of the stabilizer; the centrifugal force deflection prevention technology generates centrifugal force and orbits through the eccentric weight of the drill tool, so that the lateral cutting force of the drill bit is evenly distributed on the well wall to prevent deflection; the guided drilling deflection prevention technology prevents deflection by the centrifugal force generated by the bent outer tube downhole motor and the downhole motor driving the high-drilling speed and low-drilling speed drill bit to rotate; the drill tool bending deflection prevention technology uses a flexible joint between the stabilizers of the drill tool to make the drill pipe produce a large deflection and make periodic vortex motion forward, driving the drill bit to cut the well wall downward to prevent deflection; the composite drilling deflection prevention technology mainly uses a combination of PDC drill bit and hollow screw to prevent deflection through sliding drilling and spiral drilling. However, the above methods are all for preventing deflection while drilling, and when drilling in Antarctica, the anti-deflection process acts on the interface between the ice layer and the rock layer. The physical and mechanical properties of the materials (ice and rock) on both sides of the interface are very different, and the inclination angle of the interface may also be very large. At the same time, in order to reduce the torque required for bedrock drilling and coring during the drilling and coring process at the ice-rock interface under the polar deep ice, the rock formation drill hole must be smaller. Therefore, traditional anti-deflection devices and methods will fail, and are therefore not suitable for preventing deflection at the Antarctic ice-rock interface.
[0005] According to the needs of coring bedrock under deep polar ice, it is necessary to ensure that the coring drill bit can enter the rock vertically at the ice-rock interface to further ensure the success of coring bedrock under ice. Based on the characteristics of the wellbore structure in which the ice layer aperture is larger than the rock layer aperture during coring of bedrock under polar ice, the harsh polar working environment, the complex environment under ice, and the small designable space in the coring drill, a device and method for maintaining straightness in coring at the ice-rock interface under deep Antarctic ice is proposed. Summary of the invention
[0006] The present invention is proposed in view of the need for coring bedrock under deep polar ice and based on the basic principle of full-eye straightening drilling. In order to adapt to polar deep ice straightening drilling and coring, the existing full-eye straightening drilling method and device are greatly improved. The existing full-eye drilling method uses a stabilizer installed on the drill assembly to limit the lateral displacement of the drill bit under the action of the lateral force of the formation, but the diameter of the stabilizer is slightly smaller than the diameter of the drill bit. When coring bedrock under deep Antarctic ice, during the ice-rock interface drilling process, the upper ice layer drilling hole is larger than the bedrock drill bit. A device with a diameter similar to the ice layer drilling hole (larger than the drill bit diameter) must be used to limit the deformation and movement of the drill rod. This requires that the drill tool can be separated from the drilling straightening device to constrain the lateral displacement of the drill rod without affecting its vertical movement. Therefore, the existing full-eye drilling method and device are not suitable for bedrock coring straightening work under deep polar ice. In view of the above reasons, a device and method for coring and drilling straightening at the ice-rock interface under deep Antarctic ice are proposed.
[0007] A straight-line-keeping device for coring drilling at the ice-rock interface under deep Antarctic ice comprises a straight-line-keeping rock-entering device, which is a hollow tubular structure penetrating from top to bottom, an internal thread of the straight-line-keeping rock-entering device is arranged in the middle part, a conical tooth for fixing the bottom of the hole is arranged in the lower part, a plurality of top hole wall cutting teeth are distributed circumferentially on the top of the straight-line-keeping rock-entering device, and a hole wall cutting and ice chip discharge channel is arranged between two adjacent top hole wall cutting teeth 7 on the outer wall of the straight-line-keeping rock-entering device when lifting the drill.
[0008] Furthermore, the hollow hole inside the straight-entry rock-protecting device is of variable diameter design, the upper end hole diameter is smaller than the inner diameter of the inner thread of the straight-entry rock-protecting device, and the inner diameter of the inner thread of the straight-entry rock-protecting device is smaller than the lower end hole diameter.
[0009] Furthermore, the inner thread of the straight-entry rock-protecting device is threadedly connected with the outer thread of the drill pipe on the outer wall of the drill pipe.
[0010] Furthermore, the diameter of the drill bit is larger than the inner diameter of the inner thread of the straight-entry rock-protecting device, and the drill bit axially limits and slides in the lower end hole of the straight-entry rock-protecting device.
[0011] A method for maintaining straightness during coring and drilling at an ice-rock interface under deep Antarctic ice, using the above-mentioned device for maintaining straightness during coring and drilling at an ice-rock interface under deep Antarctic ice, comprises the following steps: S1. Send the drilling tool connected to the straight-line rock-entry device into the ice-rock interface at the bottom of the borehole. At this time, since the diameter of the straight-line rock-entry device is close to the pore diameter of the ice layer, the lateral displacement and deformation of the drill rod and the drill bit can be limited; S2. Rotate the drill pipe and the drill bit to separate them from the straight-entry rock-protecting device. At this time, the straight-entry rock-protecting device does not restrict the vertical movement of the drill pipe and the drill bit, but only restricts the lateral movement of the drill pipe and the drill bit; S3. Drilling is carried out at the ice-rock interface. At this time, due to the presence of the straight-entry rock device, the lateral displacement of the drill bit at the ice-rock interface is constrained, thereby ensuring that the drill rod and the drill bit can enter the rock straightly; S4. After the drilling and coring is completed, since the diameter of the drill bit is slightly larger than the inner diameter of the inner thread of the rock-entry device, the rock-entry device can be taken away from the bottom of the hole when the drill is lifted; S5. In order to prevent the situation that the upper ice hole shrinks and the main rock-entering device is stuck when the drill is lifted, a top hole wall cutting tooth that can cut the ice hole wall is arranged on the upper part of the rock-entering device. If the hole wall shrinks, the drill bit can be rotated to expand the hole and the drill can be lifted smoothly.
[0012] Beneficial effects of the present invention: 1. This straight-entry rock device is suitable for straight-entry rock at complex ice-rock interfaces under deep polar ice. The inner hole of the device is designed with a variable aperture, which can only constrain the lateral displacement and deformation of the drilling tool (drill bit and drill pipe) as a whole without restricting its vertical movement; 2. The straight-through rock-entry device of the present invention is connected by threads to ensure that the straight-through rock-entry device can smoothly reach the bottom of the hole; 3. The bottom conical teeth are set and the drill pipe external thread is used to connect the internal thread of the rock to ensure that the device is directly inserted into the rock. When the device reaches the bottom of the hole, the device and the drill pipe can be automatically separated in the axial direction by rotation; 4. The structure is simple and has sufficient reliability in the complex environment of deep ice wells. At the same time, it can provide sufficient lateral constraints on the drill pipe, meet the design requirements of full-eye drilling tools, and achieve the purpose of preventing deflection; 5. When lifting the drill, the design of the top cutting teeth can ensure that the entire downhole drilling equipment can be smoothly lifted out even when the ice hole shrinks. BRIEF DESCRIPTION OF THE DRAWINGS
[0013] Figure 1 is a three-dimensional schematic diagram of the present invention connected with a drilling tool; Figure 2 is a cross-sectional view of the present invention; Figure 3 is a cross-sectional view of the present invention connected with a drilling tool; Figure 4 is a bottom view of the present invention; Figure 5 It is a top view of the present invention. DETAILED DESCRIPTION
[0014] Referring to the attached drawings, a straight-line-keeping device for coring drilling at the ice-rock interface under deep Antarctic ice comprises a straight-line-keeping rock-entering device 5, which is a hollow tubular structure penetrating from top to bottom, an internal thread 4 of the straight-line-keeping rock-entering device 5 is provided in the middle portion, a conical tooth 1 for fixing the bottom of the hole is provided in the lower portion of the straight-line-keeping rock-entering device 5, a plurality of top hole wall cutting teeth 7 are distributed circumferentially at the top of the straight-line-keeping rock-entering device 5, and a hole wall cutting and ice chip discharge channel 8 is provided on the outer wall of the straight-line-keeping rock-entering device 5 between two adjacent top hole wall cutting teeth 7 when lifting the drill.
[0015] Furthermore, the hollow hole inside the straight-entry rock-protecting device 5 is of variable diameter design, the upper end hole diameter is smaller than the inner diameter of the straight-entry rock-protecting device internal thread 4, and the inner diameter of the straight-entry rock-protecting device internal thread 4 is smaller than the lower end hole diameter.
[0016] Furthermore, the internal thread 4 of the straight-entry rock device is threadedly connected to the external thread 3 of the drill pipe on the outer wall of the drill pipe 6.
[0017] Furthermore, the diameter of the drill bit 2 is larger than the inner diameter of the internal thread 4 of the straight-entry rock-entering device, and the drill bit 2 slides axially within the lower end hole of the straight-entry rock-entering device 5.
[0018] A method for maintaining straightness during coring and drilling at an ice-rock interface under deep Antarctic ice, using the above-mentioned device for maintaining straightness during coring and drilling at an ice-rock interface under deep Antarctic ice, comprises the following steps: S1. The drill connected to the rock-entering device 5 is sent into the ice-rock interface at the bottom of the borehole. At this time, since the diameter of the rock-entering device 5 is close to the pore diameter of the ice layer, the lateral displacement and deformation of the drill rod 6 and the drill bit 2 can be limited; S2. Rotate the drill rod 6 and the drill bit 2 to separate them from the straight rock-entering device 5. At this time, the straight rock-entering device 5 does not restrict the vertical movement of the drill rod 6 and the drill bit 2, but only restricts the lateral movement of the drill rod 6 and the drill bit 2; S3. Drilling is carried out at the ice-rock interface. At this time, due to the presence of the straight-entry rock device 5, the lateral displacement of the drill bit 2 at the ice-rock interface is constrained, so that the drill rod 6 and the drill bit 2 can be kept straight into the rock; S4. After the coring is completed, since the diameter of the drill bit 2 is slightly larger than the inner diameter of the internal thread 4 of the straight rock-entering device, the straight rock-entering device 5 can be taken away from the bottom of the hole when the drill is lifted; S5. In order to prevent the situation that the upper ice hole shrinks and the main rock-entry device 5 is stuck when the drill is lifted, the top hole wall cutting teeth 7 that can cut the ice hole wall are provided on the upper part of the rock-entry device 5. If the hole wall shrinks, the drill bit can be rotated to expand the hole and the drill can be lifted smoothly.
[0019] The working scheme of this straight-entry rock device is as follows: when the drill bit reaches the ice-rock interface, the drill is lifted and replaced with a coring drill bit with a straight-entry rock device 5. When the bottom of the hole is reached, the bottom-fixed conical teeth 1 of the straight-entry rock device 5 are inserted into the bottom of the hole under the action of drilling pressure, in order to restrict the rotation of the straight-entry rock device 5. After that, the drill bit rotates and disengages from the straight-entry rock device 5 to continue drilling downward. The straight-entry rock device 5 is supported on the hole wall. During this process, the straight-entry rock device 5 restricts the lateral movement of the drill bit, so that the drill rod 6 is always at the position of the borehole axis, thereby ensuring that the drill bit can enter the rock straightly. When the drill bit is lifted, the straight-entry rock device 5 can be drilled out of the hole. When the ice hole shrinks in diameter when the drill bit is lifted, the top hole wall cutting teeth 7 on the top of the straight-entry rock device 5 can be rotated by the upper drilling rig to cut the ice hole wall, open a channel, and ensure the safe exit of the downhole equipment.
[0020] Combining the above-mentioned coring process with the complex working conditions of drilling and coring at the ice-rock interface, the present invention has a simple structure and reduces the probability of failure underground; it provides sufficient lateral support to the smaller coring drill in the ice hole with a larger diameter; it can follow the coring drill along the ice hole to the ice-rock interface at the bottom of the hole; due to the large diameter of the ice hole and the small diameter of the bedrock drill bit, it must be able to detach from the drill bit after reaching the bottom of the hole, and not interfere with the small diameter drill bit drilling downwards for coring. In view of the possibility that the upper ice hole may shrink after coring the bedrock under the ice, resulting in the inability to smoothly lift the underground equipment, a top hole wall cutting tooth 7 is designed on the upper part of the straight-entry rock device. When the diameter shrinkage hinders the lifting of the drill, the purpose of expanding the channel and smoothly lifting the drill is achieved by rotating the top hole wall cutting tooth 7.
Claims
1. A device for coring and straightening the ice-rock interface under deep Antarctic ice, characterized by: The invention comprises a straight-through rock entry device (5), wherein the middle part of the straight-through rock entry device (5) is provided with an internal thread (4) of the straight-through rock entry device, the lower part of the straight-through rock entry device (5) is provided with a hole bottom fixing conical tooth (1), the top of the straight-through rock entry device (5) is provided with a plurality of top hole wall cutting teeth (7) distributed in the circumferential direction, and the outer wall of the straight-through rock entry device (5) is provided with a hole wall cutting and ice chip discharge channel (8) when the drill is lifted, between two adjacent top hole wall cutting teeth (7).
2. The device for maintaining straightness when coring and drilling at the ice-rock interface under deep Antarctic ice according to claim 1, characterized in that: The hollow hole inside the straight rock entry device (5) is of variable diameter design, the upper end hole diameter is smaller than the inner diameter of the straight rock entry device internal thread (4), and the inner diameter of the straight rock entry device internal thread (4) is smaller than the lower end hole diameter.
3. The device for maintaining straightness when coring and drilling at the ice-rock interface under deep Antarctic ice according to claim 2, characterized in that: The inner thread (4) of the rock-entry device is threadedly connected to the outer thread (3) of the drill rod on the outer wall of the drill rod (6).
4. The device for maintaining straightness when coring and drilling at the ice-rock interface under deep Antarctic ice according to claim 3, characterized in that: The diameter of the drill bit (2) is larger than the inner diameter of the internal thread (4) of the straight-line rock-entry device, and the drill bit (2) is axially limited and slidable in the lower end hole of the straight-line rock-entry device (5).
5. A method for maintaining straightness during coring and drilling at the ice-rock interface under deep Antarctic ice, using the device for maintaining straightness during coring and drilling at the ice-rock interface under deep Antarctic ice as claimed in claim 4, characterized in that: The steps include: S1. Send the drill connected to the rock-entry device (5) into the ice-rock interface at the bottom of the borehole. At this time, since the diameter of the rock-entry device (5) is close to the pore diameter of the ice layer, the lateral displacement and deformation of the drill rod (6) and the drill bit (2) can be limited; S2. Rotate the drill rod (6) and the drill bit (2) to separate them from the straight-entry rock-protecting device (5). At this time, the straight-entry rock-protecting device (5) does not restrict the vertical movement of the drill rod (6) and the drill bit (2), but only restricts the lateral movement of the drill rod (6) and the drill bit (2); S3. Drilling is carried out at the ice-rock interface. At this time, due to the presence of the straight-entry rock device (5), the lateral displacement of the drill bit (2) at the ice-rock interface is constrained, thereby ensuring that the drill rod (6) and the drill bit (2) can be kept straight into the rock; S4. After the drilling and coring is completed, since the diameter of the drill bit (2) is slightly larger than the inner diameter of the inner thread (4) of the straight rock device, the straight rock device (5) can be taken away from the bottom of the hole when the drill is lifted; S5. In order to prevent the upper ice hole from shrinking and blocking the main rock-entry device (5) when the drill is lifted, a top hole wall cutting tooth (7) capable of cutting the ice hole wall is provided on the upper part of the rock-entry device (5). If the hole wall shrinks, the drill tool can be rotated to expand the hole and the drill can be lifted smoothly.