A reverse circulation continuous coring drill suitable for use in Antarctic ice and ice-boulder interbeds

Abstract

The application discloses a reverse circulation continuous coring drilling tool suitable for Antarctic ice layers and ice rock interlayers, which 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 main body, a plurality of groups of PDC cutting teeth and hard alloy scraper cutting teeth are distributed at the bottom of the drill bit main body at intervals, a fence is arranged at the bottom of the outer edge of the drill bit main body, a plurality of groups of gauge PDC cutting teeth and gauge hard alloy scraper cutting teeth are distributed at the bottom of the fence at intervals, a central passage is arranged in the middle of the drill bit main body, and a plurality of drill bit bottom spray holes are annularly arranged on the drill bit main body outside the central passage; the reverse circulation drilling tool provided with the composite drill bit is suitable for ice layers and ice rock interlayers, and a sealing cover does not need to be additionally arranged outside the drill bit during actual drilling; the composite drill bit with the fence can automatically form a sealing effect on drilling fluid during drilling; and the reverse circulation continuous coring drilling tool can realize continuous coring and drilling without stopping, and can realize the effect of continuous drilling from the ice layer to the ice rock interlayer.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of drilling tools, and particularly relates to a reverse circulation continuous coring drill suitable for Antarctic ice layer and ice-rock interlayer. BACKGROUND

[0002] International Antarctic scientific research competition is increasingly fierce, and it is of great significance to many scientific fields such as global temperature change and glacier dynamics to quickly drill through the ice layer, ice-rock interlayer and rock layer and obtain ice core, rock core and other samples. However, the conventional coring by positive circulation drilling produces a large amount of debris and mud, and the drilling fluid directly contacts the ice hole wall, which may cause pollution of the polar environment. The flow of the ice layer covering the Antarctic bedrock may also cause the drilling hole to be quickly closed, causing a stuck drill accident. In addition, the Antarctic environment is harsh, and the construction period available for drilling each year is very short, so it is urgent to have a portable, environmentally friendly and efficient coring drill to complete deep ice drilling in a short construction period.

[0003] The air reverse circulation continuous coring drilling technology can continuously obtain core 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, the time for lifting and lowering the drill can be greatly shortened, and the pollution to the environment can be reduced. The conventional hard alloy drill bit is suitable for ice layer drilling, and the PDC drill bit needs to be replaced when the ice-rock interlayer is drilled. The hard alloy and PDC composite drill bit can be used in the ice layer and the ice-rock interlayer at the same time, and the PDC drill bit does not need to be replaced after the drill bit passes through the ice layer, so the drilling in the ice-rock interlayer can be continued, which further saves time. SUMMARY

[0004] The technical problem to be solved by the present application is to provide a reverse circulation continuous coring drill suitable for Antarctic ice layer and ice-rock interlayer, which is environmentally friendly, non-polluting, reduces auxiliary time and improves the efficiency of coring drilling.

[0005] A reverse circulation continuous coring drill suitable for Antarctic ice layer and ice-rock interlayer, comprising a composite drill bit and a double-wall connecting pipe, the composite drill bit being connected to the lower end of the double-wall connecting pipe.

[0006] The composite drill bit comprises PDC cutting teeth, hard alloy scraper cutting teeth, drill bit bottom spray holes, gauge PDC cutting teeth, gauge hard alloy scraper cutting teeth and a fence.

[0007] The bottom of the drill bit body is spaced apart and provided with multiple groups of PDC cutting teeth and hard alloy scraper cutting teeth, the bottom of the outer edge of the drill bit body is provided with a fence, the bottom of the fence is spaced apart and provided with multiple groups of gauge PDC cutting teeth and gauge hard alloy scraper cutting teeth, the central passage is provided in the middle of the drill bit body, and the outer circle of the drill bit body is annularly distributed with multiple drill bit bottom spray holes penetrating the central passage.

[0008] The double-wall connecting pipe comprises a clamping and breaking device, an ejecting hole, a drill tool outer pipe, a connecting pipe inner pipe and a drill bit connecting pipe, a connecting inner pipe and a double-wall drill pipe joint connecting pipe, a clamping and breaking device, a lower end of the connecting pipe inner pipe and the drill bit connecting pipe is connected with an inner wall of a drill bit body, a lower end of the clamping and breaking device is connected with an upper end of the connecting pipe inner pipe and the drill bit connecting pipe, an upper end of the clamping and breaking device is connected with a lower end of the connecting inner pipe and the double-wall drill pipe joint connecting pipe; a lower end of the drill tool outer pipe is connected with an upper end of the drill bit body, and an annular space gap is arranged between the drill tool outer pipe and the connecting pipe inner pipe and the drill bit connecting pipe, the connecting inner pipe and the double-wall drill pipe joint connecting pipe, and the clamping and breaking device, and the annular space gap is communicated with a drill bit bottom jet hole.

[0009] The clamping and breaking device is uniformly provided with a plurality of ejecting holes in the upper circumference, and the ejecting holes are directed outward and inward and inclined upward by 45 degrees.

[0010] The present application has the following beneficial effects:

[0011] Compared with other reverse circulation technologies, the present application designs a reverse circulation drill tool provided with a composite drill bit, which is suitable for ice layers and ice rock interbeds, and does not need to be provided with a sealing cover outside the drill bit during actual drilling, and the composite drill bit with a fence automatically forms a sealing effect on the drilling fluid during drilling, and the present application realizes continuous clamping and coring without stopping drilling, the effect of ice layer to ice rock interbed without stopping drilling, improves the coring efficiency, and realizes the portable, environmentally friendly and efficient drilling and coring of the Antarctic deep ice and ice rock interbeds. BRIEF DESCRIPTION OF DRAWINGS

[0012] Figure 1 is a sectional view of the present application;

[0013] Figure 2 is a bottom view of the present application. DETAILED DESCRIPTION

[0014] In order to make the purpose, technical scheme and advantages of the present application more clear, the present application is further described in detail below in combination with the drawings and examples.

[0015] Referring to the drawings, a reverse circulation continuous coring drill tool suitable for Antarctic ice layers and ice rock interbeds comprises a composite drill bit and a double-wall connecting pipe, and the composite drill bit is connected to a lower end of the double-wall connecting pipe.

[0016] The composite drill bit comprises PDC cutting teeth 101, hard alloy scraper cutting teeth 102, a drill bit bottom jet hole 103, a gauge PDC cutting tooth 104, a gauge hard alloy scraper cutting tooth 105 and a fence 106.

[0017] The drill bit body bottom is provided with multiple groups of PDC cutting teeth 101 and hard alloy scraper cutting teeth 102 at intervals, the drill bit body outer edge bottom is provided with a fence 106, the fence 106 bottom is provided with multiple groups of gauge PDC cutting teeth 104 and gauge hard alloy scraper cutting teeth 105 at intervals, the drill bit body middle part is provided with a through center passage, and the drill bit body outer circle of the center passage is annularly provided with multiple through drill bit bottom spray holes 103;

[0018] The double-wall connecting pipe comprises opposite clamping devices 201, injection holes 202, a drill pipe outer pipe 203, a connecting pipe inner pipe and drill bit connecting pipe 204, a connecting pipe inner pipe and double-wall drill pipe joint connecting pipe 205, clamping and injection devices 206, the lower end of the connecting pipe inner pipe and drill bit connecting pipe 204 is connected with the inner wall of the drill bit body, the lower end of the clamping and injection devices 206 is connected with the upper end of the connecting pipe inner pipe and drill bit connecting pipe 204, and the upper end of the clamping and injection devices 206 is connected with the lower end of the connecting pipe inner pipe and double-wall drill pipe joint connecting pipe 205; the lower end of the drill pipe outer pipe 203 is connected with the upper end of the drill bit body, and annular space gaps are arranged between the drill pipe outer pipe 203 and the connecting pipe inner pipe and drill bit connecting pipe 204, the connecting pipe inner pipe and double-wall drill pipe joint connecting pipe 205 and the clamping and injection devices 206, and the annular space gaps are communicated with the drill bit bottom spray holes 103.

[0019] The clamping and injection devices 206 are uniformly provided with multiple injection holes 202 on the circumference, the injection holes 202 are directed from outside to inside and obliquely upward by 45°.

[0020] Further, the ratio of the total area of the injection holes 202 to the total area of the drill bit bottom spray holes 103 is 1.3:1.

[0021] Further, the clamping and injection devices 206 are provided with two groups of non-contact opposite clamping devices 201 opposite in the axial direction.

[0022] Further, the opposite clamping devices 201 are triangular protrusions.

[0023] Further, the composite drill bit has an overall concave structure, and the slope is 15°-30°.

[0024] The continuous coring method of the embodiment comprises the following steps:

[0025] When drilling, the gas delivered through the upper drill pipe first enters the annular gap of the double-wall connecting pipe, and continues to flow downward in the annular gap until it passes through the injection hole 202. At this time, part of the fluid passes through the injection hole 202 to generate an upward high-speed jet flow in the break and injection device 206, and a low-pressure area below the high-speed jet flow. The other part of the fluid continues to flow downward along the annular gap until it is sprayed to the hole bottom through the bottom spray hole 103. Due to the suction force of the low-pressure area and the existence of the blocking resistance of the gas by the concave structure of the composite drill bit and the structure of the surrounding barrier 106, most of the gas sprayed to the hole bottom through the bottom spray hole 103 flows to the central passage of the double-wall connecting pipe inner tube (the connecting pipe 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 break and injection device 206), ensuring the formation of reverse circulation.

[0026] The ratio of the total area of the bottom spray hole 103 to the injection hole 202 is 1.3:1, which meets the requirements of hole bottom chip removal and cooling, and ensures that the low-pressure area generated at the injection hole 202 has sufficient suction force on the hole bottom. The composite drill bit 1 continues to drill in the rock formation to form an ice core (or an ice-rock interlayer core). As the drilling depth increases, the length of the ice core gradually increases. When the ice core touches the opposite break device 201, the protruding part of the opposite break device 201 applies a force perpendicular to the movement direction of the ice core to the ice core, causing the ice core to tilt and break. The two oppositely arranged opposite break devices 201 can better ensure the breakage of the ice core. After breaking, the core is pushed by the subsequent ice core and the flow impact of the drilling fluid along the central passage of the double-wall connecting pipe inner tube, realizing automatic core breakage without tripping. In addition, when drilling in the ice layer, the hard alloy scraper cutting tooth 102 is responsible for cutting the ice layer, and the PDC cutting tooth 101 is responsible for cutting the ice-rock interlayer. Therefore, after drilling through the ice layer and reaching the ice-rock interlayer, it is not necessary to trip and replace the drill bit.

Claims

1. A reverse circulation coring drill suitable for use in Antarctic ice and ice-boulder layers, characterised in that: The composite drill bit is connected to the lower end of the double-wall connecting pipe. The composite drill bit comprises PDC cutting teeth (101), cemented carbide drag bit cutting teeth (102), drill bit bottom jet holes (103), gauge PDC cutting teeth (104), gauge cemented carbide drag bit cutting teeth (105) and a fence (106). The drill bit body bottom is spaced apart and provided with multiple groups of PDC cutting teeth (101) and cemented carbide drag bit cutting teeth (102), the drill bit body outer edge bottom is provided with a fence (106), the fence (106) bottom is spaced apart and provided with multiple groups of gauge PDC cutting teeth (104) and gauge cemented carbide drag bit cutting teeth (105), the drill bit body middle part is provided with a through center passage, and the drill bit body outer circle located in the center passage is annularly distributed with multiple through drill bit bottom jet holes (103). The double-wall connecting pipe comprises opposite clamping devices (201), injection holes (202), a drilling tool outer pipe (203), a connecting pipe inner pipe and drill bit connecting pipe (204), a connecting pipe and double-wall drill rod joint connecting pipe (205), clamping and injection devices (206), the connecting pipe inner pipe and drill bit connecting pipe (204) lower end is connected to the drill bit body inner wall, the clamping and injection devices (206) lower end is connected to the connecting pipe inner pipe and drill bit connecting pipe (204) upper end, the clamping and injection devices (206) upper end is connected to the connecting pipe and double-wall drill rod joint connecting pipe (205) lower end, the drilling tool outer pipe (203) lower end is connected to the drill bit body upper end, and the drilling tool outer pipe (203) is provided with an annular space gap between the connecting pipe inner pipe and drill bit connecting pipe (204), the connecting pipe and double-wall drill rod joint connecting pipe (205) and the clamping and injection devices (206), and the annular space gap is communicated with the drill bit bottom jet holes (103). The clamping and injection devices (206) are circumferentially and uniformly provided with multiple injection holes (202), the injection holes (202) are directed from outside to inside and obliquely upward by 45°.

2. The anti-circulation continuous coring drill for Antarctic ice layer and ice-rock interlayer according to claim 1, characterized in that: The total area ratio of the injection holes (202) to the drill bit bottom jet holes (103) is 1.3:

1.

3. The reverse circulation continuous coring drill for Antarctic ice and ice-boulder interlayer according to claim 1, characterized in that: The clamping and injection devices (206) are provided with two groups of non-contact opposite clamping devices (201) in the axial direction.

4. The reverse circulation continuous coring drill for Antarctic ice and ice-boulder interlayer according to claim 1, characterized in that: The opposite clamping devices (201) are triangular protrusions.

5. The reverse circulation continuous coring drill for Antarctic ice and ice-boulder interlayer according to claim 1, characterized in that: The composite drill bit is an overall concave structure with a slope of 15°-30°.

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