CN112282636A

CN112282636A - Screw core drill

Info

Publication number: CN112282636A
Application number: CN202011283819.5A
Authority: CN
Inventors: 宋刚; 李小洋; 陈晓林; 刘春生; 崔淑英; 牛庆磊; 寇贝贝; 陈根龙; 李博; 李晶; 张欣; 赵明; 韩泽龙; 蒋亚峰
Original assignee: Institute of Exploration Technology Chinese Academy of Geological Sciences
Current assignee: Institute of Exploration Technology Chinese Academy of Geological Sciences
Priority date: 2020-11-17
Filing date: 2020-11-17
Publication date: 2021-01-29

Abstract

The invention discloses a screw core drill, comprising: the outer tube assembly with be used for the suit in the outer tube assembly with the inner tube assembly of outer tube assembly joint, outer tube assembly first end is used for being connected with the drilling rod, the second end is equipped with the drill bit subassembly with outer tube assembly rotatable coupling, the inner tube assembly includes screw motor subassembly, be connected with screw motor subassembly first end and be used for salvaging the subassembly with outer tube assembly joint and with the sampling subassembly of screw motor subassembly second end connection, sampling subassembly wears inside the drill bit subassembly, screw motor subassembly is connected with the drill bit subassembly transmission, in order to drive the drill bit subassembly and rotate. The drilling speed of the screw core drilling tool is higher, and the drilling efficiency is higher; on the other hand, the drill bit subassembly can adopt the faster diamond bit of rotational speed requirement, and diamond bit can grind into the rock dust with large granule detritus, and the rock dust can be along with outside mud discharge drilling to can avoid the detritus to pile up the problem that causes buried drill, sticking of tool.

Description

Screw core drill

Technical Field

The invention relates to the technical field of marine drilling sampling, in particular to a screw core drill bit.

Background

Reef limestone, also known as bio-skeleton limestone, is a limestone composed of bio-skeletons in an in-situ fixed growth state and is widely distributed near the reefs in south China sea. With the increasing development of the south sea in recent years, reef limestone has received increasing attention as a typical rock type around the reef island. In the aspects of geological survey in sea areas, island engineering construction and the like, parameters such as cause, deposition environment, engineering mechanical property and the like of reef limestone are urgently needed to be known, and the acquisition of an undisturbed sample becomes the best means for solving the property of the reef limestone.

The method has the remarkable characteristics that slurry is leaked out, rock debris cannot be discharged out of a shaft, great risks of buried drilling and stuck drilling exist, and the construction period is easily prolonged. In addition, seabed hard rock is mostly granite and other strata, is very hard, adopts conventional roller bit or PDC drill bit to creep into very low efficiency, can't satisfy the consumption of marine high cost. Therefore, the screw core drill has high drilling efficiency and can avoid the occurrence of accidents of buried drilling and drill sticking.

Disclosure of Invention

In order to solve the technical problems, the invention provides the screw core drill with high drilling efficiency and capable of avoiding the occurrence of buried drill and drill sticking accidents.

In order to achieve the purpose, the invention provides the following scheme:

the invention provides a screw core drill, comprising: the outer tube assembly with be used for the suit in the outer tube assembly with the inner tube assembly of outer tube assembly joint, outer tube assembly first end be used for with the drilling rod be connected, the second end be equipped with outer tube assembly rotatable coupling's drill bit subassembly, the inner tube assembly include screw motor subassembly, with screw motor subassembly first end is connected and is used for with the salvage subassembly of outer tube assembly joint and with the sample subassembly of screw motor subassembly second end connection, the sample subassembly is worn inside the drill bit subassembly, screw motor subassembly with the drill bit subassembly transmission is connected, in order to drive the drill bit subassembly rotates.

Further, the screw motor assembly comprises a stator assembly and a rotor assembly rotatably arranged inside the stator assembly, the stator assembly is connected with the fishing assembly, and the rotor assembly is in transmission connection with the drill bit assembly.

Further, the sampling assembly is rotatably connected with the rotor assembly.

Further, still include with the biography that the rotor subassembly is connected is turned round the pipe, biography is turned round the tub outer wall and is equipped with the external splines, drill bit subassembly inner wall be equipped with external splines complex internal spline, the sampling subassembly through the single action subassembly with it is connected to turn round the pipe rotation to pass.

Furthermore, the single-action assembly comprises a connecting rod in threaded connection with the torque transmission pipe, a rotating sleeve rotatably sleeved on the connecting rod and a positioning assembly arranged on the connecting rod and used for preventing the rotating sleeve from falling off; and a first thrust bearing is arranged between the rotating sleeve and the torque transmission pipe, and the positioning assembly compresses the rotating sleeve through a second thrust bearing.

Furthermore, the positioning assembly comprises a positioning nut in threaded connection with the connecting rod and a first spring sleeved on the connecting rod, one end of the first spring abuts against the positioning nut, and the other end of the first spring abuts against the second thrust bearing.

Further, the sampling assembly comprises a transition piece in threaded connection with the single-action assembly, an adjusting joint in threaded connection with the transition piece, and a sampling cylinder in threaded connection with the adjusting joint; the sampling tube is the tube structure that forms for including two at least arc tube concatenations, the sampling tube is kept away from the outside of adjusting joint one end be equipped with the jump ring seat that the sampling tube screw thread closed soon.

Further, the drill bit subassembly including be used for with the transmission of screw motor subassembly is connected turn round nipple joint, first end with the transmission turn round nipple joint threaded connection's connecting pipe group and set up in the drill bit of connecting pipe group second end, connecting pipe group includes a plurality of connecting pipe, connecting pipe group pass through the bearing group with the outer tube assembly rotates to be connected, the bearing group includes radial bearing and the axial bearing of a plurality of distribution in turn.

Furthermore, a buffer component is arranged between the connecting pipe group and the outer pipe assembly, and the buffer component comprises a third thrust bearing and a second spring, wherein the third thrust bearing is abutted against the connecting pipe group, one end of the second spring is abutted against the outer pipe assembly, and the other end of the second spring is abutted against the third thrust bearing.

Furthermore, the salvaging component comprises a salvaging spear component, an elastic clamp and a suspension joint, wherein the salvaging spear component, the elastic clamp and the suspension joint are sequentially connected, the outer pipe assembly is clamped, the suspension joint is connected with the screw motor component, the suspension joint is hollow, a water inlet hole for slurry to enter is formed in the outer circumferential side surface of the suspension joint, so that the slurry enters the screw motor component through the suspension joint, the suspension joint is located at the downstream of the water inlet hole in the slurry flowing direction, and a sealing ring is arranged on the outer circumferential side wall of the suspension joint.

Compared with the prior art, the invention has the following technical effects:

the invention relates to a screw core drill, comprising: the outer tube assembly with be used for the suit in the outer tube assembly with the inner tube assembly of outer tube assembly joint, outer tube assembly first end is used for being connected with the drilling rod, the second end is equipped with the drill bit subassembly with outer tube assembly rotatable coupling, the inner tube assembly includes screw motor subassembly, be connected with screw motor subassembly first end and be used for salvaging the subassembly with outer tube assembly joint and with the sampling subassembly of screw motor subassembly second end connection, sampling subassembly wears inside the drill bit subassembly, screw motor subassembly is connected with the drill bit subassembly transmission, in order to drive the drill bit subassembly and rotate.

When the drilling device is used, the outer pipe assembly is connected to a drill rod, and the outer pipe assembly is lowered to the bottom of a well in a mode of additionally connecting the drill rod. Then, the inner pipe assembly is placed into the outer pipe assembly through the fisher, the inner pipe assembly is clamped with the outer pipe assembly after being in place, and the fisher is separated from the inner pipe assembly. And mud is introduced from the drill rod, the screw motor assembly is driven to rotate when the mud passes through the screw motor assembly, and the drill bit assembly is driven to rotate when the screw motor assembly rotates, so that the screw core drilling tool can drill into the rock. After the completion, transfer the fisher from the drilling rod to salvage the well head with the inner tube assembly, unpack the sample subassembly and get the core.

According to the arrangement, the drill bit component of the screw core drilling tool is driven to rotate by the screw motor component, and the outer pipe assembly can also rotate, so that the rotating speed of the drill bit component is the superposition of the rotating speed of the screw motor component and the rotating speed of the outer pipe assembly, and the rotating speed of the drill bit component is higher, so that the drilling speed of the screw core drilling tool is higher, and the drilling efficiency is higher; on the other hand, the drill bit subassembly can adopt the faster diamond bit of rotational speed requirement, so, diamond bit can grind into the rock dust with large granule detritus, and is thinner littleer than the detritus that gear wheel and PDC drill bit produced, and the rock dust can be along with outside mud discharge drilling to can avoid the detritus to pile up the problem that causes buried drill, sticking to bore.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings needed in the embodiments will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art to obtain other drawings without creative efforts.

FIGS. 1 and 2 are generally schematic structural views of an inner tube assembly in accordance with an embodiment of the present invention;

FIGS. 3 and 4 are schematic structural views of an outer tube assembly according to an embodiment of the present invention;

FIGS. 5 and 6 are schematic views showing the structure of a screw core drill according to an embodiment of the present invention as a whole;

FIG. 7 is a view of section I of FIG. 5;

fig. 8 is a partial view of section ii of fig. 5.

Description of reference numerals: 100. an inner tube assembly; 200. an outer tube assembly; 110. a fishing spear assembly; 111. snapping; 112. a water inlet hole; 113. a suspension joint; 114. a seal ring; 120. a screw motor assembly; 121. a stator assembly; 122. a rotor assembly; 130. a torsion transmission pipe; 131. an external spline; 132. a water outlet hole; 140. a single-acting assembly; 141. a connecting rod; 142. rotating the sleeve; 143. a first thrust bearing; 144. a second thrust bearing; 145. positioning a nut; 146. a first spring; 150. a sampling assembly; 151. a transition piece; 152. adjusting the joint; 153. a sampling tube; 154. a clamp spring seat; 201. a torque transmission nipple; 202. a drill bit; 203. a radial bearing; 204. an axial bearing; 205. a third thrust bearing; 206. a second spring; 207. a righting ring; 208. a connecting pipe; 209. connecting a sleeve; 210. a reducer union; 211. the bullet blocks the head.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

In order to make the aforementioned objects, features and advantages of the present invention comprehensible, embodiments accompanied with figures are described in further detail below.

As shown in fig. 1 to 8, an embodiment of the present invention provides a screw core drill, which includes an outer tube assembly 200 and an inner tube assembly 100 for fitting inside the outer tube assembly 200 and being in snap-fit connection with the outer tube assembly 200. The outer tube assembly 200 is adapted to be connected to a drill pipe at a first end. For example, as shown in FIG. 4, the first end of the outer tube assembly 200 may be provided with a reducer union 210 for threaded connection to a drill pipe. The second end of the outer tube assembly 200 is provided with a drill bit assembly rotatably connected to the outer tube assembly 200. The inner tube assembly 100 includes a screw motor assembly 120, a fishing assembly connected to a first end of the screw motor assembly 120 and adapted to snap-fit to the outer tube assembly 200, and a sampling assembly 150 connected to a second end of the screw motor assembly 120. The screw motor assembly 120 is drivingly connected to the drill bit assembly to rotate the drill bit assembly. The sampling assembly 150 passes inside the drill bit assembly. The screw motor assembly 120 is connected with the fishing assembly, and the fishing assembly is connected with the outer tube assembly 200 in a clamping manner, so that finally, the reverse torque generated when the screw motor assembly 120 drives the drill bit assembly to rotate is transmitted to the outer tube assembly 200 through the fishing assembly, and the drill bit assembly and the outer tube assembly 200 generate relative motion.

The specific using process is as follows: when the pipe joint is used, the outer pipe assembly 200 is connected to a drill pipe, and the outer pipe assembly 200 is lowered to the bottom of a well in a mode of additionally connecting the drill pipe. Then, the inner pipe assembly 100 is lowered into the outer pipe assembly 200 by the fisher until the inner pipe assembly 100 is in place and then is clamped with the outer pipe assembly 200, so that the fisher is separated from the inner pipe assembly 100. Mud is passed from the drill pipe and drives the screw motor assembly 120 to rotate as the mud passes by the screw motor assembly 120 and the drill bit assembly to rotate as the screw motor assembly 120 rotates, thereby enabling the screw core drill to drill into the rock. After completion, the overshot is lowered down the drill pipe to fish the inner pipe assembly 100 up the wellhead and to disassemble the sampling assembly 150 for coring.

According to the arrangement, the drill bit component of the screw core drilling tool is driven to rotate by the screw motor component 120, and the outer pipe assembly 200 can also rotate, so that the rotating speed of the drill bit component is the superposition of the rotating speed of the screw motor component 120 and the rotating speed of the outer pipe assembly 200, the rotating speed of the drill bit component is higher, and on one hand, the drilling speed of the screw core drilling tool is higher, and the drilling efficiency is higher; on the other hand, the drill bit subassembly can adopt the faster diamond bit 202 of rotational speed requirement, and like this, diamond bit 202 can grind into the rock dust with large granule detritus, and is thinner and littleer than the detritus that roller cone and PDC drill bit produced, and the rock dust can be along with outside mud discharge drilling to can avoid the detritus to pile up the problem that causes buried drill, sticking to bore. Therefore, the screw core drill provided by the invention can be suitable for drilling and extracting seabed hard rocks and reef limestone.

Referring to fig. 1-2, in some embodiments, progressive cavity motor assembly 120 includes a stator assembly 121 and a rotor assembly 122 rotatably disposed within stator assembly 121. For example, a double helical cavity is formed in stator assembly 121, and rotor assembly 122 is a single helical joint, and rotor assembly 122 is driven to rotate by introducing drilling fluid into stator assembly 121. It should be noted that the screw motor belongs to the products in the prior art, and the principle thereof is not the focus of the discussion herein, and is not described herein again. Stator assembly 121 is connected to the fishing assembly and rotor assembly 122 is drivingly connected to the drill bit assembly. When letting in mud or drilling fluid, the drilling fluid enters into stator module 121 in drive rotor subassembly 122 and rotates, and stator module 121 is connected with fishing subassembly to on transmitting the outer tube assembly 200 through fishing subassembly with reaction torque, rotor subassembly 122 drives the drill bit subassembly and rotates, so that the drill bit subassembly can punch on the rock.

In some embodiments, sampling assembly 150 is rotatably coupled to rotor assembly 122. So configured, sampling assembly 150 does not rotate with rotor assembly 122 as rotor assembly 122 rotates.

Referring to FIG. 1, in some embodiments, the screw sampling drill further includes a torque tube 130 connected to the drill assembly. Referring to fig. 7, the outer wall of the torque transmission tube 130 is provided with external splines 131, and the inner wall of the bit assembly is provided with internal splines for engaging with the external splines 131. When the inner tube assembly 100 is placed inside the outer tube assembly 200 and the inner tube assembly 100 is snapped in place, the inner spline and the outer spline 131 are engaged with each other, and the rotor assembly 122 drives the drill bit assembly to rotate through the torsion tube 130, the inner spline and the outer spline 131. Optionally, a torque tube 130 is threadedly connected to the drill assembly. The torque transmission tube 130 is hollow, and a water outlet hole 132 is formed in a side wall of the torque transmission tube 130, so that the drilling fluid in the rotor assembly 122 can flow out along the water outlet hole 132 of the torque transmission tube 130.

Referring to FIG. 1, a sampling assembly 150 is rotatably coupled to the drive tube by a single action assembly 140. In some embodiments, the single acting assembly 140 includes a connecting rod 141 screwed with the torsion tube 130, a rotating sleeve 142 rotatably fitted on the connecting rod 141, and a positioning assembly mounted on the connecting rod 141 for preventing the rotating sleeve 142 from falling off. The sampling assembly 150 is connected to the rotating sleeve 142. A first thrust bearing 143 is arranged between the rotating sleeve 142 and the torque transmission pipe 130, and the positioning assembly presses the rotating sleeve 142 through a second thrust bearing 144 sleeved on the connecting rod 141. The first thrust bearing 143 and the second thrust bearing 144 ensure that the rotating sleeve 142 can still rotate freely when the positioning assembly presses against the rotating sleeve 142.

Referring to fig. 1, in some embodiments, the positioning assembly includes a positioning nut 145 threadedly coupled to the connecting rod 141 and a first spring 146 sleeved on the connecting rod 141. One end of the first spring 146 abuts against the positioning nut 145, the other end of the first spring abuts against the second thrust bearing 144, the positioning nut 145 compresses the first spring 146 by screwing the positioning nut 145, the first spring 146 strictly prohibits the second thrust bearing 144, and the second thrust bearing 144 compresses the rotating sleeve 142. So set up, can conveniently adjust the packing force of locating component to rotating sleeve 142.

Referring to FIG. 1, in some embodiments, sampling assembly 150 includes a transition piece 151 threadably coupled to single-action assembly 140, an adjustment fitting 152 threadably coupled to transition piece 151, and a sampling barrel 153 threadably coupled to adjustment fitting 152. For example, the first end of the transition piece 151 is provided with an internal thread, the rotating sleeve 142 is provided with an external thread matching with the internal thread, and the transition piece 151 and the rotating sleeve 142 are screwed. The second end of the transition piece 151 is provided with a threaded hole, the adjusting joint 152 is provided with a stud matched with the threaded hole, and the stud on the adjusting joint 152 is screwed into the threaded hole and fixed by a fixing nut. The position of the sampling tube 153 can be adjusted by adjusting the screwing length of the adjusting head. The sampling tube 153 has a cylindrical structure formed by splicing at least two arc-shaped tubes. The outside of the end of the sampling tube 153 far from the adjusting joint 152 is provided with a snap spring seat 154 screwed with the sampling tube 153. When the sampling device is used, after the inner pipe assembly 100 is fished to a wellhead, the sampling cylinder 153 is unscrewed from the adjusting joint 152, and then the clamp spring seat 154 is detached, so that the sampling cylinder 153 can be opened to take out a core sample. And by setting the sampling cylinder 153 in a splicing form, the core sample can be conveniently taken out and the integrity of the sample can be ensured. Referring to fig. 8, optionally, a centralizing ring 207 is provided within the drill bit assembly. The centralizing ring 207 is in running fit with the outer wall of the sampling cylinder 153 to prevent the sampling cylinder 153 from being skewed, and the sampling cylinder 153 and the drill bit assembly are always concentric, so that the sampling quality is better.

Referring to fig. 3, in some embodiments, the drill bit assembly includes a torque coupling sub 201 for drivingly connecting with the progressive cavity motor assembly 120, a connection tube set having a first end threadedly connected with the torque coupling sub 201, and a drill bit 202 disposed at a second end of the connection tube set. The connecting pipe group comprises a plurality of connecting pipes 208 which are sequentially in threaded connection, and the number of the connecting pipes 208 can be set according to actual needs. The connecting tube set is rotatably connected with the outer tube assembly 200 through a bearing set, and the bearing set comprises a plurality of radial bearings 203 and axial bearings 204 which are alternately distributed. The number of the radial bearings 203 and the number of the axial bearings 204 can be set according to actual needs, and the number of the radial bearings 203 and the number of the axial bearings 204 in fig. 3 are two respectively. The radial bearing 203 is used for bearing the radial force of the drill bit assembly, and the axial bearing 204 is used for bearing the axial force of the drill bit assembly, and both of them can adopt commercially available bearings. Referring to fig. 3, to facilitate mounting of the drill bit assembly to the outer tube assembly 200, the second end of the outer tube assembly 200 is provided with a plurality of connecting sleeves 209 that are in turn threadably connected. The connection sleeve 209 is capable of supporting and axially positioning the drill bit assembly.

Referring to FIG. 3, in some embodiments, a buffer member is disposed between the connecting tube set and the outer tube assembly 200. The buffer component comprises a third thrust bearing 205 which is abutted against the connecting pipe set and a second spring 206 with one end abutted against the outer pipe assembly 200 and the other end abutted against the third thrust bearing 205. The third thrust bearing 205 and the second spring 206 are both sleeved on the connecting pipe 208. So set up, the impact force that the drill bit subassembly received can have the buffering subassembly to absorb to reduce the impact that the bearing received in the bearing group, prolong the life-span of bearing group.

Referring to fig. 2, in some embodiments, the fishing assembly includes a fishing spear assembly 110, an elastic clip 111 for engaging with the outer tube assembly 200, and a suspension joint 113 for connecting with the screw motor assembly 120, all connected in series. It should be noted that the fishing spear assembly 110 is a product in the prior art, and the construction thereof is not focused on the discussion herein, and is not described in detail herein. Similarly, the latch 111 is also a product in the prior art, and can cooperate with the latch stop 211 on the outer tube assembly 200 to transmit torque for transmitting the reaction torque received by the stator assembly 121 of the screw motor assembly 120 to the outer tube assembly 200. The suspension joint 113 is hollow inside and has an outer circumferential side surface provided with a water inlet hole 112 for the slurry to enter through the suspension joint 113 to the screw motor assembly 120. A packing 114 is provided on an outer circumferential side wall of the hanger joint 113 downstream of the water inlet hole 112 in the slurry flow direction. By providing the seal ring 114, mud or drilling fluid can be completely introduced into the screw motor assembly 120 from the inlet opening 112, thereby avoiding energy waste.

The principle and the implementation mode of the present invention are explained by applying specific examples in the present specification, and the above descriptions of the examples are only used to help understanding the method and the core idea of the present invention; meanwhile, for a person skilled in the art, according to the idea of the present invention, the specific embodiments and the application range may be changed. In view of the above, the present disclosure should not be construed as limiting the invention.

Claims

1. A screw core drill, comprising: the outer tube assembly with be used for the suit in the outer tube assembly with the inner tube assembly of outer tube assembly joint, outer tube assembly first end be used for with the drilling rod be connected, the second end be equipped with outer tube assembly rotatable coupling's drill bit subassembly, the inner tube assembly include screw motor subassembly, with screw motor subassembly first end is connected and is used for with the salvage subassembly of outer tube assembly joint and with the sample subassembly of screw motor subassembly second end connection, the sample subassembly is worn inside the drill bit subassembly, screw motor subassembly with the drill bit subassembly transmission is connected, in order to drive the drill bit subassembly rotates.

2. The progressive cavity core drilling tool of claim 1 wherein the progressive cavity motor assembly includes a stator assembly and a rotor assembly rotatably disposed within the stator assembly, the stator assembly being coupled to the fishing assembly, the rotor assembly being drivingly coupled to the drill bit assembly.

3. The screw coring bit of claim 2, wherein the sampling assembly is rotationally coupled to the rotor assembly.

4. The progressive cavity core drill of claim 3 further comprising a torque tube connected to the rotor assembly, the torque tube having an outer wall with external splines and an inner wall with internal splines that mate with the external splines, the sampling assembly being rotationally connected to the torque tube by a single action assembly.

5. The screw core drill as set forth in claim 4, wherein the single-acting assembly comprises a connecting rod threadedly connected to the torque transmission pipe, a rotating sleeve rotatably fitted over the connecting rod, and a positioning assembly mounted on the connecting rod for preventing the rotating sleeve from falling off; and a first thrust bearing is arranged between the rotating sleeve and the torque transmission pipe, and the positioning assembly compresses the rotating sleeve through a second thrust bearing.

6. The screw coring bit of claim 5, wherein the positioning assembly comprises a positioning nut in threaded connection with the connecting rod and a first spring sleeved on the connecting rod, wherein one end of the first spring abuts against the positioning nut and the other end of the first spring abuts against the second thrust bearing.

7. The screw coring bit of claim 4, wherein the sampling assembly comprises a transition piece threadedly connected to the single action assembly, an adjustment fitting threadedly connected to the transition piece, and a sampling barrel threadedly connected to the adjustment fitting; the sampling tube is the tube structure that forms for including two at least arc tube concatenations, the sampling tube is kept away from the outside of adjusting joint one end be equipped with the jump ring seat that the sampling tube screw thread closed soon.

8. The screw core drilling tool as set forth in claim 1, wherein said drill bit assembly includes a torque coupling sub for driving connection with said screw motor assembly, a connecting tube set having a first end threadedly connected to said torque coupling sub, and a drill bit disposed at a second end of said connecting tube set, said connecting tube set including a plurality of connecting tubes, said connecting tube set being rotatably connected to said outer tube assembly by a bearing set, said bearing set including a plurality of alternately disposed radial and axial bearings.

9. The screw core drill as set forth in claim 8 wherein a damping member is disposed between the connecting tube set and the outer tube assembly, the damping member including a third thrust bearing abutting the connecting tube set and a second spring having one end abutting the outer tube assembly and the other end abutting the third thrust bearing.

10. The screw core drilling tool as set forth in claim 1, wherein the fishing assembly comprises a fishing spear assembly, an elastic clip for being engaged with the outer tube assembly, and a suspension joint for being connected with the screw motor assembly, which is hollow inside and has an inlet hole on an outer circumferential side surface thereof for allowing slurry to enter therethrough, and a packing is provided on an outer circumferential side wall of the suspension joint downstream of the inlet hole in a slurry flow direction.