Reverse circulation continuous coring drilling tool suitable for Antarctic ice layer and ice rock interlayer

Abstract

The reverse circulation continuous coring drilling tool suitable for the Antarctic ice layer and the ice rock interlayer comprises a composite drill bit and a double-wall connecting pipe, and the composite drill bit is connected to the lower end of the double-wall connecting pipe; the composite drill bit comprises a drill bit body, multiple sets of PDC cutting teeth and hard alloy scraper cutting teeth are distributed at the bottom of the drill bit body at intervals, a fence is arranged at the bottom of the outer edge of the drill bit body, multiple sets of gauge PDC cutting teeth and gauge hard alloy scraper cutting teeth are distributed at the bottom of the fence at intervals, and a through center channel is formed in the middle of the drill bit body. A plurality of through drill bit bottom spraying holes are annularly distributed in the drill bit main body on the outer ring of the central channel; the reverse circulation drilling tool provided with the composite drill bit is designed, the reverse circulation drilling tool is suitable for an ice layer and an ice rock interlayer, a packing cover does not need to be additionally arranged on the outer side of the drill bit in the actual drilling process, and the composite drill bit with the fence automatically forms the packing effect on drilling fluid in the drilling process. And drilling is not stopped from the ice layer to the ice rock interlayer.

Description

Technical Field

[0001] The invention relates to the technical field of drilling tools, and in particular to a reverse circulation continuous coring drilling tool suitable for Antarctic ice layers and ice-rock interlayers. Background Art

[0002] International competition in Antarctic scientific research is becoming increasingly fierce. Rapidly drilling through ice layers, ice-rock interlayers, and rock layers, and obtaining ice cores, rock cores and other samples are of great significance to many scientific fields such as global temperature change and glacier dynamics. However, conventional positive circulation drilling and coring will produce a large amount of debris and mud, and the drilling fluid will be in direct contact with the ice hole wall, which may cause pollution to the polar environment. The flow of the ice layer covering the Antarctic bedrock will also cause the borehole to close quickly, causing a stuck drill accident. In addition, the Antarctic environment is harsh, and the construction period available for drilling is very short each year. In order to complete deep ice drilling in a short construction period, a portable, environmentally friendly, and efficient coring drill is urgently needed.

[0003] Air reverse circulation continuous coring drilling technology can achieve continuous coring without lifting the drill during the drilling process, and the gas mainly flows in the double-wall drill pipe channel. If it is applied to Antarctic drilling, it can greatly shorten the time of lifting and lowering the drill, while reducing pollution to the environment. Conventional carbide drill bits are suitable for ice drilling, and when drilling into ice-rock interlayers, the drill needs to be lifted and replaced with a PDC drill bit. Carbide and PDC composite drill bits can be used in both ice layers and ice-rock interlayers. When the drill bit passes through the ice layer, there is no need to lift the drill to replace the PDC drill bit, and drilling in the ice-rock interlayer can continue, which further saves time. Summary of the invention

[0004] The technical problem to be solved by the present invention is to provide a reverse circulation continuous coring drill suitable for Antarctic ice layers and ice-rock interlayers. The invention is environmentally friendly and pollution-free, reduces auxiliary time and can improve the efficiency of drilling and coring.

[0005] A reverse circulation continuous coring drill suitable for Antarctic ice layers and ice-rock interlayers, comprising a composite drill bit and a double-walled connecting pipe, wherein the composite drill bit is connected to the lower end of the double-walled connecting pipe; The composite drill bit includes PDC cutting teeth, carbide scraper cutting teeth, bottom spray holes of the drill bit, diameter-protected PDC cutting teeth, diameter-protected carbide scraper cutting teeth and enclosures; A plurality of groups of PDC cutting teeth and carbide scraper cutting teeth are arranged at intervals at the bottom of the drill bit body, a baffle is arranged at the bottom of the outer edge of the drill bit body, a plurality of groups of diameter-protected PDC cutting teeth and diameter-protected carbide scraper cutting teeth are arranged at intervals at the bottom of the baffle, a central channel is arranged through the middle of the drill bit body, and a plurality of drill bit bottom spray holes are arranged in an annular shape on the drill bit body located on the outer circle of the central channel; The double-wall connecting pipe comprises a facing breaking device, an ejection hole, a drilling tool outer pipe, an inner pipe of the connecting pipe and a drill bit connecting pipe, a connecting pipe connecting the inner pipe and a double-wall drill pipe joint, and a breaking and ejection device. The lower end of the inner pipe of the connecting pipe and the drill bit connecting pipe is connected to the inner wall of the drill bit body, the lower end of the breaking and ejection device is connected to the upper end of the inner pipe of the connecting pipe and the drill bit connecting pipe, and the upper end of the breaking and ejection device is connected to the lower end of the connecting pipe connecting the inner pipe and the double-wall drill pipe joint; the lower end of the drilling tool outer pipe is connected to the upper end of the drill bit body, and an annular space gap is provided between the drilling tool outer pipe, the inner pipe of the connecting pipe and the drill bit connecting pipe, the connecting pipe connecting the inner pipe and the double-wall drill pipe joint, and the breaking and ejection device, and the annular space gap is connected to the bottom spray hole of the drill bit; A plurality of ejection holes are evenly distributed on the circumference of the cutting and ejection device, and the ejection holes are directed from outside to inside and obliquely upward at 45 degrees.

[0006] The beneficial effects of the present invention are: Compared with other reverse circulation technologies, the present invention designs a reverse circulation drill equipped with a composite drill bit, which is suitable for both ice layers and ice-rock interlayers. In actual drilling, there is no need to install a sealing cover on the outside of the drill bit. The composite drill bit with a baffle automatically forms a sealing effect on the drilling fluid during drilling. At the same time, the present invention achieves the effect of continuous coring without stopping, and continuous drilling from ice layers to ice-rock interlayers, thereby improving the coring efficiency and achieving the goal of drilling and coring in Antarctic deep ice and ice-rock interlayers in a portable, environmentally friendly and efficient manner. BRIEF DESCRIPTION OF THE DRAWINGS

[0007] Figure 1 is a cross-sectional view of the present invention; Figure 2 It is a bottom view of the present invention. DETAILED DESCRIPTION

[0008] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments.

[0009] Referring to the attached drawings, a reverse circulation continuous coring drill suitable for Antarctic ice layers and ice-rock interlayers comprises a composite drill bit and a double-walled connecting pipe, wherein the composite drill bit is connected to the lower end of the double-walled connecting pipe; The composite drill bit includes a PDC cutting tooth 101, a cemented carbide scraper cutting tooth 102, a drill bit bottom spray hole 103, a diameter-protected PDC cutting tooth 104, a diameter-protected cemented carbide scraper cutting tooth 105 and a fence 106; A plurality of groups of PDC cutting teeth 101 and carbide scraper cutting teeth 102 are arranged at intervals at the bottom of the drill bit body, a baffle 106 is arranged at the bottom of the outer edge of the drill bit body, a plurality of groups of diameter-protected PDC cutting teeth 104 and diameter-protected carbide scraper cutting teeth 105 are arranged at intervals at the bottom of the baffle 106, a central channel is arranged through the middle of the drill bit body, and a plurality of drill bit bottom spray holes 103 are arranged in an annular shape on the drill bit body located at the outer circle of the central channel; The double-walled connecting pipe comprises a facing breaking device 201, an ejection hole 202, a drilling tool outer pipe 203, an inner pipe of the connecting pipe and a drill bit connecting pipe 204, a connecting pipe 205 connecting the inner pipe and a double-walled drill pipe joint, and a breaking and ejection device 206. The lower end of the inner pipe of the connecting pipe and the drill bit connecting pipe 204 is connected to the inner wall of the drill bit body, the lower end of the breaking and ejection device 206 is connected to the upper end of the inner pipe of the connecting pipe and the drill bit connecting pipe 204, and the upper end of the breaking and ejection device 206 is connected to the lower end of the connecting pipe 205 connecting the inner pipe and the double-walled drill pipe joint; the lower end of the drilling tool outer pipe 203 is connected to the upper end of the drill bit body, and an annular space is provided between the drilling tool outer pipe 203, the inner pipe of the connecting pipe and the drill bit connecting pipe 204, the connecting pipe 205 connecting the inner pipe and the double-walled drill pipe joint, and the breaking and ejection device 206, and the annular space is communicated with the bottom ejection hole 103 of the drill bit; A plurality of ejection holes 202 are evenly distributed on the circumference of the cutting and ejection device 206 , and the ejection holes 202 are oriented from outside to inside and obliquely upward at 45°.

[0010] Furthermore, the ratio of the total area of ​​the injection holes 202 to the total area of ​​the injection holes 103 at the bottom of the drill bit is 1.3:1.

[0011] Furthermore, two sets of non-contacting opposing cutting devices 201 are provided on the cutting and ejecting device 206 along the axial direction thereof.

[0012] Furthermore, the opposite breaking device 201 is a triangular protrusion.

[0013] Furthermore, the composite drill bit has an overall concave structure with a slope of 15°~30°.

[0014] The continuous coring method of the present embodiment comprises the following steps: During drilling, the gas transported down through the upper drill pipe first enters the annular space of the double-walled connecting pipe, and continues to flow downward in the annular space until it passes through the ejection hole 202. A portion of the fluid passes through the ejection hole 202, generating an upward high-speed jet in the cut-off and ejection device 206, and generating a low-pressure area below the high-speed jet. The other portion of the fluid continues to flow downward along the annular space until it is ejected to the bottom of the hole through the bottom ejection hole 103. Due to the suction force of the low-pressure area, the concave structural shape of the composite drill bit, and the sealing resistance of the enclosure 106 structure to the gas, most of the gas ejected to the bottom of the hole through the bottom ejection hole 103 flows to the central channel of the inner tube of the double-walled connecting rod (the inner tube of the connecting tube and the drill bit connecting tube 204, the connecting tube 205 connecting the inner tube and the double-walled drill pipe joint, and the cut-off and ejection device 206), thereby ensuring the formation of reverse circulation.

[0015] The design of a total area ratio of the bottom spray hole 103 to the ejection hole 202 of 1.3:1 meets the chip removal and cooling requirements at the bottom of the hole, while ensuring that the low-pressure zone generated at the ejection hole 202 has sufficient suction force on the bottom of the hole. The composite drill bit 1 continues to drill in the rock formation to form an ice core (or a core of an ice-rock interlayer). As the drilling depth increases, the length of the ice core gradually increases. When the ice core touches the opposite breaking device 201, the protruding part of the opposite breaking device 201 applies a force perpendicular to the direction of core movement to the ice core, causing the core to tilt and break. The two opposite breaking devices 201 arranged opposite to each other can better ensure the breaking of the ice core. After breaking, the core returns along the central channel of the inner tube of the double-wall connecting rod under the subsequent top delivery of the ice core and the flow impact of the drilling fluid, so that the core is automatically broken and obtained without lifting the drill. In addition, when drilling in ice layers, the carbide scraper cutting teeth 102 are responsible for cutting the ice layers, and in ice-rock interlayers, the PDC cutting teeth 101 are responsible for cutting and drilling. Therefore, after drilling through the ice layer and reaching the ice-rock interlayer, there is no need to lift the drill and replace the drill bit.

Claims

1. A reverse circulation continuous coring drill suitable for Antarctic ice layers and ice-rock interlayers, characterized by: It comprises a composite drill bit and a double-wall connecting pipe, wherein the composite drill bit is connected to the lower end of the double-wall connecting pipe; The composite drill bit comprises a PDC cutting tooth (101), a cemented carbide scraper cutting tooth (102), a drill bit bottom spray hole (103), a diameter-protected PDC cutting tooth (104), a diameter-protected cemented carbide scraper cutting tooth (105) and a retaining block (106); A plurality of groups of PDC cutting teeth (101) and carbide scraper cutting teeth (102) are arranged at intervals at the bottom of the drill bit body, a baffle (106) is arranged at the bottom of the outer edge of the drill bit body, a plurality of groups of diameter-retaining PDC cutting teeth (104) and diameter-retaining carbide scraper cutting teeth (105) are arranged at intervals at the bottom of the baffle (106), a central channel is arranged through the middle of the drill bit body, and a plurality of drill bit bottom spray holes (103) are arranged in an annular shape on the drill bit body located outside the central channel; The double-walled connecting pipe comprises a facing breaking device (201), an ejection hole (202), a drilling tool outer pipe (203), an inner pipe of the connecting pipe and a drill bit connecting pipe (204), a connecting pipe (205) connecting the inner pipe and a double-walled drill pipe joint, and a breaking and ejection device (206); the lower end of the inner pipe of the connecting pipe and the drill bit connecting pipe (204) is connected to the inner wall of the drill bit body, and the lower end of the breaking and ejection device (206) is connected to the upper end of the inner pipe of the connecting pipe and the drill bit connecting pipe (204). The upper end of the snap-off and ejection device (206) is connected to the lower end of the connecting pipe (205) connecting the inner tube and the double-wall drill pipe joint; the lower end of the drill tool outer tube (203) is connected to the upper end of the drill bit body; an annular space is provided between the drill tool outer tube (203) and the connecting pipe, the inner tube and the drill bit connecting pipe (204), the connecting pipe (205) connecting the inner tube and the double-wall drill pipe joint, and the snap-off and ejection device (206); the annular space is communicated with the spray hole (103) at the bottom of the drill bit; A plurality of ejection holes (202) are evenly distributed on the circumference of the snapping and ejection device (206), and the ejection holes (202) are oriented from outside to inside and obliquely upward at 45 degrees.

2. A reverse circulation continuous coring drill suitable for Antarctic ice layers and ice-rock interlayers according to claim 1, characterized in that: The ratio of the total area of ​​the injection holes (202) to the total area of ​​the injection holes (103) at the bottom of the drill bit is 1.3:

1.

3. A reverse circulation continuous coring drill suitable for Antarctic ice layers and ice-rock interlayers according to claim 1, characterized in that: Two groups of non-contacting opposing clamping devices (201) are arranged on the clamping and ejecting device (206) in opposite directions along the axial direction thereof.

4. A reverse circulation continuous coring drill suitable for Antarctic ice layers and ice-rock interlayers according to claim 1, characterized in that: The opposite snapping device (201) is a triangular protrusion.

5. A reverse circulation continuous coring drill suitable for Antarctic ice layers and ice-rock interlayers according to claim 1, characterized in that: The composite drill bit has an overall concave structure with a slope of 15°~30°.

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