阅读说明：本技术 内卡式钻杆打捞工具及其打捞方法 (Internal clamping type drill rod fishing tool and fishing method thereof ) 是由 王传留 陈彦宇 杨虎伟 邵国杰 张献振 高晓亮 马少明 李鹏 田宏杰 于 2019-10-15 设计创作，主要内容包括：本发明涉及一种内卡式钻杆打捞工具及其打捞方法,该工具包括从左到右同轴依次布设的外管、拧紧环、高低压三通阀、单作用液压缸、推力杆、芯轴、弹性卡爪组件和螺旋套筒。通过弹性卡爪卡紧钻杆接头内台阶实现打捞工具与断裂钻杆的快速连接；还具备解卡功能,通过高低压转换阀,可快速将打捞工具与断裂钻杆柱分离。该打捞工具及其打捞方法用于钻探过程中钻杆断裂或掉落等事故的快速打捞,改变了现有的打捞方式,解决了采用公锥或母锥造扣困难,打捞过程中钻杆易发生二次掉落等问题,具有使用方便、打捞成功率高等优点。(The invention relates to an inner clamping type drill rod fishing tool and a fishing method thereof. The step in the drill rod joint is clamped by the elastic clamping jaw to realize the quick connection of the fishing tool and the broken drill rod; still possess the unfreezing function, through high-low pressure change-over valve, can separate fishing tool and fracture drilling rod string fast. The fishing tool and the fishing method thereof are used for quickly fishing accidents such as breakage or falling of the drill rod in the drilling process, change the existing fishing mode, solve the problems that the drilling rod is difficult to make by adopting a male cone or a female cone, and the drill rod is easy to drop secondarily in the fishing process, and have the advantages of convenience in use, high fishing success rate and the like.)

1. The utility model provides an interior card formula drilling rod fishing tool, includes outer tube and spiral sleeve, the right-hand member outer wall fixed connection of spiral sleeve and outer tube, its characterized in that:

the utility model discloses a hydraulic cylinder, including outer tube and spiral sleeve, the top of outer tube and spiral sleeve is equipped with high-low pressure three-way valve, nonoculture pneumatic cylinder, distance rod and dabber from a left side to the right side is coaxial in proper order, the top terminal surface of high-low pressure three-way valve is connected with the bottom terminal surface of nonoculture pneumatic cylinder, the inside recess of outer tube is equipped with the second shoulder face of spacing nonoculture pneumatic cylinder, the distance rod sets up in the inside recess right-hand member of outer tube, and the distance rod can follow the inside recess axial displacement of outer tube, the distance rod contains a disc face and many push rods, many push rods are the circumference interval from the one end of disc face and set up and outwards extend, the other end of disc face and the cylinder head fixed connection of nonoculture pneumatic cylinder, the one end and the outer tube fixed connection of dabber, the elasticity jack catch.

2. The internally-clamped drill rod fishing tool of claim 1, wherein: the high-low pressure three-way valve comprises a cavity, an outer valve core body, an inner valve core body and a first spring, wherein the inner valve core body and the first spring are arranged inside the cavity, one end of the inner valve core body is provided with an accommodating groove for accommodating one end of the first spring, the other end of the first spring is abutted against the inner end face of the cavity, the outer valve core body is arranged outside the cavity, and one end of the outer valve core body is fixedly connected with the other end of the inner valve core body through a through hole of the cavity.

3. The internally-clamped drill rod fishing tool of claim 2, wherein: the outer edge of the inner valve core body is in a tapered shape relative to the position of the through hole, so that a P port is formed between the inner valve core body and the through hole, a T port and an A port are formed in the cavity, the T port and the A port are arranged on the periphery of the cavity and penetrate through the inside and the outside of the cavity, the inner valve core body is provided with conducting holes communicated with the A port in different positions, and the P port and the A port are conducted or closed by controlling the positions of the inner valve core body and the outer valve core body.

4. The internally-clamped drill rod fishing tool of claim 3, wherein: the outer wall of the cavity is also provided with a drainage groove which is communicated with the T port.

5. The internally-clamped drill rod fishing tool of claim 2, wherein: the outer edge of the cavity is provided with at least one sealing groove for accommodating the sealing ring.

6. The inside-clamp drill rod fishing tool of any one of claims 1-5, wherein: elasticity jack catch subassembly includes elasticity jack catch, thread fixing ring, second spring and spacing ring from left to right coaxial set gradually between the outside fringe of the inside of elasticity jack catch and dabber, and thread fixing ring and elasticity jack catch fixed connection, thread fixing ring's internal diameter has certain clearance with the external diameter of dabber, the dabber is equipped with spacing step to carry on spacingly to the axial position to the spacing ring, thread fixing ring's internal diameter has certain clearance with the external diameter of dabber, and the external diameter of spacing ring has certain clearance with the internal diameter of elasticity jack catch, the second spring sets up so that the elasticity jack catch is along axial displacement and elastic recovery between thread fixing ring and the spacing ring.

7. The inside-clamp drill rod fishing tool of any one of claims 1-5, wherein: the outer edge of the head of the mandrel is provided with a biconical surface, the biconical surface comprises a middle top end and conical surfaces positioned on two sides of the top end, and the conical surface on the outer side of the top end is uniformly provided with a plurality of gauge strips and a plurality of first alloy sheets for cutting burrs and the like at the broken drill rod.

8. The internally-clamped drill rod fishing tool of claim 7, wherein: be equipped with the cladding on the elasticity jack catch piece of the inboard circular conical surface in top of dabber, be equipped with a plurality of barbs on the elasticity jack catch piece, a plurality of barbs set up in the periphery of elasticity jack catch piece along axial interval.

9. The inside-clamp drill rod fishing tool of any one of claims 1-5, wherein: the spiral sleeve comprises spiral blades, 3 guide rods, a guide ring and a plurality of second alloy sheets, the guide rods are fixedly connected with the axial outer diameter of the spiral blades, the guide ring is fixedly connected with the right end of the guide rods, and the second alloy sheets are uniformly arranged on the inner diameter circumference of the guide ring.

10. A fishing method of an inner clamping type drill rod fishing tool is characterized by comprising the following steps:

the method comprises the following steps: firstly, the internally-clamped drill rod fishing tool as claimed in any one of claims 1 to 9 is conveyed to a position where a drill rod is broken or falls, the central axis of an orifice fishing drill rod string is aligned with the central axis of a broken drill rod string at the bottom of a hole by using a spiral sleeve, a power head of a drilling machine rotates forwards, the burr edge of the broken drill rod end is ground by using the spiral sleeve, the power head of the drilling machine advances, and a mandrel of the internally-clamped drill rod fishing tool is conveyed into the hole of the broken drill rod string at the bottom of the hole;

step two: then low-pressure water is introduced, the low-pressure water enters a piston cavity of the single-action hydraulic cylinder to push the thrust rod to move rightwards, the elastic clamping jaw assembly moves rightwards and opens along the axial direction under the thrust action of the thrust rod, the low-pressure water is cut off, the single-action hydraulic cylinder keeps low pressure all the time, then the drill rod column at the orifice is lifted slowly, the elastic clamping jaw piece is in contact with the step surface of the inner wall of the broken drill rod, and the inner-clamping type drill rod fishing tool clamps the step surface of the inner wall of the broken drill rod; and the power head of the drilling machine retreats to lift the drill rod column, so that the broken drill rod at the bottom of the hole can be salvaged.

Technical Field

The invention relates to the technical field of drilling and well drilling machinery, in particular to an inner clamping type drill rod fishing tool and a fishing method thereof.

Background

During the drilling construction process, accidents in the borehole often occur due to unclear knowledge of the formation condition, improper selection of the drilling process or misoperation of operators and the like. When the drill pipe is broken, a special tool is needed for fishing treatment. Generally, a male cone is adopted to carry out button making and fishing from an inner hole of a drill rod, or a female cone is adopted to carry out button making and fishing from the outer wall of the drill rod. If the drill pipe is broken under the condition of large bore diameter of the drill hole, the accident head is held on the wall of the drill hole, and the accident source cannot be found by adopting a male cone or a female cone, so that inconvenience is brought to accident treatment. For some drill rod joints with high hardness, buttons cannot be made on the broken surfaces of drill rods, and after the drill rods are broken, the drill rods cannot be fished by using male cones or female cones. Therefore, there is a need to develop a drill pipe fishing tool to solve the above problems.

Therefore, in view of the above-mentioned drawbacks, the designer of the present invention, through careful research and design, integrates experience and results of related industries for many years, and researches and designs an inner clamping type drill rod fishing tool and a fishing method thereof, so as to overcome the above-mentioned drawbacks.

Disclosure of Invention

The invention aims to provide an inner clamping type drill rod fishing tool and a fishing method thereof, which are convenient to use and high in reliability; it also provides a better unfreezing function, reduces damage to the broken drill string, and avoids the situation in the hole from becoming more complex.

In order to solve the problems, the invention discloses an inner clamping type drill rod fishing tool, which comprises an outer pipe and a spiral sleeve, wherein the spiral sleeve is fixedly connected with the outer wall of the right end of the outer pipe, and the inner clamping type drill rod fishing tool is characterized in that:

the utility model discloses a hydraulic cylinder, including outer tube and spiral sleeve, the top of outer tube and spiral sleeve is equipped with high-low pressure three-way valve, nonoculture pneumatic cylinder, distance rod and dabber from a left side to the right side is coaxial in proper order, the top terminal surface of high-low pressure three-way valve is connected with the bottom terminal surface of nonoculture pneumatic cylinder, the inside recess of outer tube is equipped with the second shoulder face of spacing nonoculture pneumatic cylinder, the distance rod sets up in the inside recess right-hand member of outer tube, and the distance rod can follow the inside recess axial displacement of outer tube, the distance rod contains a disc face and many push rods, many push rods are the circumference interval from the one end of disc face and set up and outwards extend, the other end of disc face and the cylinder head fixed connection of nonoculture pneumatic cylinder, the one end and the outer tube fixed connection of dabber, the elasticity jack catch.

Wherein: the high-low pressure three-way valve comprises a cavity, an outer valve core body, an inner valve core body and a first spring, wherein the inner valve core body and the first spring are arranged inside the cavity, one end of the inner valve core body is provided with an accommodating groove for accommodating one end of the first spring, the other end of the first spring is abutted against the inner end face of the cavity, the outer valve core body is arranged outside the cavity, and one end of the outer valve core body is fixedly connected with the other end of the inner valve core body through a through hole of the cavity.

Wherein: the outer edge of the inner valve core body is in a tapered shape relative to the position of the through hole, so that a P port is formed between the inner valve core body and the through hole, a T port and an A port are formed in the cavity, the T port and the A port are arranged on the periphery of the cavity and penetrate through the inside and the outside of the cavity, the inner valve core body is provided with conducting holes communicated with the A port in different positions, and the P port and the A port are conducted or closed by controlling the positions of the inner valve core body and the outer valve core body.

Wherein: the outer wall of the cavity is also provided with a drainage groove which is communicated with the T port.

Wherein: the outer edge of the cavity is provided with at least one sealing groove for accommodating the sealing ring.

Wherein: elasticity jack catch subassembly includes elasticity jack catch, thread fixing ring, second spring and spacing ring from left to right coaxial set gradually between the outside fringe of the inside of elasticity jack catch and dabber, and thread fixing ring and elasticity jack catch fixed connection, thread fixing ring's internal diameter has certain clearance with the external diameter of dabber, the dabber is equipped with spacing step to carry on spacingly to the axial position to the spacing ring, thread fixing ring's internal diameter has certain clearance with the external diameter of dabber, and the external diameter of spacing ring has certain clearance with the internal diameter of elasticity jack catch, the second spring sets up so that the elasticity jack catch is along axial displacement and elastic recovery between thread fixing ring and the spacing ring.

Wherein: the outer edge of the head of the mandrel is provided with a biconical surface, the biconical surface comprises a middle top end and conical surfaces positioned on two sides of the top end, and the conical surface on the outer side of the top end is uniformly provided with a plurality of gauge strips and a plurality of first alloy sheets for cutting burrs and the like at the broken drill rod.

Wherein: be equipped with the cladding on the elasticity jack catch piece of the inboard circular conical surface in top of dabber, be equipped with a plurality of barbs on the elasticity jack catch piece, a plurality of barbs set up in the periphery of elasticity jack catch piece along axial interval.

Wherein: the spiral sleeve comprises spiral blades, 3 guide rods, a guide ring and a plurality of second alloy sheets, the guide rods are fixedly connected with the axial outer diameter of the spiral blades, the guide ring is fixedly connected with the right end of the guide rods, and the second alloy sheets are uniformly arranged on the inner diameter circumference of the guide ring.

Also discloses a fishing method of the internal clamping type drill rod fishing tool, which is characterized by comprising the following steps:

the method comprises the following steps: firstly, conveying an inner clamping type drill rod fishing tool to a position where a drill rod is broken or falls off, aligning the central axis of an orifice fishing drill rod column with the central axis of a hole bottom broken drill rod column by using a spiral sleeve, rotating a power head of a drilling machine forward, grinding a burr edge of a broken drill rod end by using the spiral sleeve, advancing the power head of the drilling machine, and conveying a core shaft of the inner clamping type drill rod fishing tool into a hole of the hole bottom broken drill rod column;

step two: then low-pressure water is introduced, the low-pressure water enters a piston cavity of the single-action hydraulic cylinder to push the thrust rod to move rightwards, the elastic clamping jaw assembly moves rightwards and opens along the axial direction under the thrust action of the thrust rod, the low-pressure water is cut off, the single-action hydraulic cylinder keeps low pressure all the time, then the drill rod column at the orifice is lifted slowly, the elastic clamping jaw piece is in contact with the step surface of the inner wall of the broken drill rod, and the inner-clamping type drill rod fishing tool clamps the step surface of the inner wall of the broken drill rod; and the power head of the drilling machine retreats to lift the drill rod column, so that the broken drill rod at the bottom of the hole can be salvaged.

According to the structure, the internal clamping type drill rod fishing tool and the fishing method thereof have the following effects:

1. has the advantages of convenient use, high reliability and the like;

2. still possess the unfreezing function, if the downthehole condition is complicated, can be fast with fishing tool carry out the hole outside, prevent the accident and worsen, reduce the loss.

3. Compared with a male-cone or female-cone fishing tool, the internal clamping type drill rod fishing tool does not need to be buckled, so that the damage to a broken drill rod string can be obviously reduced in the fishing process, and the situation in a hole is prevented from becoming more complex.

The details of the present invention can be obtained from the following description and the attached drawings.

Drawings

Fig. 1 shows an overall structure diagram of the internal clamping type drill rod fishing tool of the invention.

Fig. 2 shows the overall structure of the elastic claw of the invention when it is opened.

Figure 3 shows a schematic view of the thrust rod structure of the present invention.

Fig. 4 shows a schematic view of the structure of the elastic claw of the invention.

Fig. 5 shows a schematic diagram of the high-low pressure three-way valve structure of the present invention.

Reference numerals:

1-an outer pipe, 2-a spiral sleeve, 3-a tightening ring, 4-a cavity, 5-a single-action hydraulic cylinder, 6-a thrust rod, 7-an elastic jaw, 8-a mandrel, 10-a high-low pressure three-way valve, 11-an outer valve core body, 12-an inner valve core body, 13-a first spring, 14-a sealing ring, 21-a spiral blade, 22-a guide rod, 24-a guide ring, 23-a second alloy sheet, 31-a first alloy sheet, 32-a diameter-protecting strip, 40-an elastic jaw component, 41-a thread fixing ring, 42-a second spring and 43-a limiting ring; 1-2-drainage holes and 1-3-drill rod connecting threads; a port 4-1-T, a port 4-2-A, a port 4-4-drainage groove and a port 4-5-P; 6-1-disc surface, 6-2 push rod; 7-1-elastic claw sheet, 7-2-barb; 8-2-double conical surface.

Detailed Description

Referring to fig. 1 and 2, the inside-grip drill pipe fishing tool of the present invention is shown.

The inner clamping type drill rod fishing tool comprises an outer pipe 1 and a spiral sleeve 2 which are coaxially and sequentially arranged from left to right, and the spiral sleeve 2 is fixedly connected with the outer wall of the right end of the outer pipe 1. The outer pipe 1 and the spiral sleeve 2 are internally and coaxially provided with a tightening ring 3, a high-low pressure three-way valve 10, a single-action hydraulic cylinder 5, a thrust rod 6 and a mandrel 8 from left to right in sequence, the tightening ring 3, the high-low pressure three-way valve 10 and the single-action hydraulic cylinder 5 are sequentially arranged in an inner groove of the outer pipe 1 from left to right, the leftmost end of the inner groove of the outer pipe 1 is provided with a drill rod connecting thread 1-3, the left side of the drill rod connecting thread 1-3 is provided with an internal thread for spirally fixing the tightening ring 3, the tightening ring 3 axially fixes the high-low pressure three-way valve 10 and the single-action hydraulic cylinder 5 through a first shoulder surface of the inner groove of the outer pipe 1, the top end surface of the high-low pressure three-way valve 10 is connected with the bottom end surface of the single-action hydraulic cylinder 5, a rubber sealing ring is arranged at the joint of, the thrust rod 6 is arranged at the right end of the inner groove of the outer pipe 1, the thrust rod 6 can axially move in the inner groove of the outer pipe 1, meanwhile, the thrust rod 6 comprises a disc surface 6-1 and a plurality of push rods 6-2, the push rods 6-2 are circumferentially arranged at intervals from one end of the disc surface 6-1 and extend outwards, a plurality of through holes for the push rods 6-2 to extend out are formed in the right end of the outer pipe 1, the other end of the disc surface 6-1 is fixedly connected with the cylinder head of the single-action hydraulic cylinder 5, and therefore when the cylinder head of the single-action hydraulic cylinder 5 extends and retracts, the thrust rod 6 can perform corresponding extending and retracting operation and can extend and retract outwards from the through hole of the outer pipe 1.

The one end of dabber 8 and the right-hand member axle center position fixed connection of outer tube 1, elasticity jack catch subassembly 40 sets up in the outside of dabber 8, and the tail end of elasticity jack catch subassembly 40 and push rod 6-2 stretch out the terminal surface of outer tube 1 and link to each other, from this, through the hydraulic stretching effect of high-low pressure three-way valve 10 and single-action pneumatic cylinder 5, realize the flexible of distance rod 6 and elasticity jack catch subassembly 40, the concertina movement of elasticity jack catch subassembly 40 on dabber 8 and in the spiral sleeve realizes the salvage function.

Referring to fig. 5, the high-pressure and low-pressure three-way valve 10 includes a cavity 4, an outer valve core 11, an inner valve core 12, a sealing ring 14 and a first spring 13, the inner valve core 12 and the first spring 13 are disposed inside the cavity 4, one end of the inner valve core 12 is provided with an accommodating groove for accommodating one end of the first spring 13, the other end of the first spring 13 abuts against an inner end face of the cavity 4, the outer valve core 11 is disposed outside the cavity 4, one end of the outer valve core 11 is fixedly connected with the other end of the inner valve core 12 through a through hole of the cavity 4, the outer edge of the inner valve core 12 is in a tapered shape relative to the through hole, so as to form a P port 4-5 between the inner valve core 12 and the through hole, and the outer edge of the cavity 4 is provided with at least one sealing groove for accommodating the. When assembling the high-low pressure three-way valve 10, the inner valve core body 12 and the first spring 13 are firstly installed inside the cavity 4, and then the outer valve core body 11 and the inner valve core body 12 are fixedly connected. The sealing ring 14 is arranged on the outer wall of the cavity 4. The inner part of the cavity 4 is provided with a T port 4-1 and an A port 4-2, the T port 4-1 and the A port 4-2 are arranged on the periphery of the cavity 4 and penetrate through the inner part and the outer part of the cavity 4, the inner valve core body 12 is provided with a through hole which can be communicated with the A port 4-2 at different positions, and as shown in the figure, the through hole penetrates through the peripheral wall of the sealing groove of the inner valve core body 12, so that the P port 4-5 and the A port 4-2 can be communicated or closed by controlling the positions of the inner valve core body and the outer valve core body. The outer wall of the cavity 4 is also provided with a drainage groove 4-4, and the drainage groove 4-4 is communicated with the T port 4-1, so that the T port 4-1 of the high-low pressure three-way valve 10 can be installed in any radial direction. After low-pressure water is cut off, the inner valve core body and the outer valve core body are quickly moved left to close the P ports 4-5 under the action of the first spring 13, so that low pressure is always kept in a piston cavity of the single-action hydraulic cylinder 5, the elastic clamping jaw is locked, the elastic clamping jaw is prevented from moving left along the axial direction, and the reliability of the fishing tool is improved.

Referring to fig. 1, 2 and 4, elasticity jack catch assembly 40 includes elasticity jack catch 7, thread fixing ring 41, second spring 42 and spacing ring 43 from left to right coaxially set up in proper order between the inside of elasticity jack catch 7 and the outer fringe of dabber 8, and thread fixing ring 41 and elasticity jack catch 7 fixed connection, the internal diameter of thread fixing ring 41 has certain clearance with the external diameter of dabber 8, dabber 8 is equipped with spacing step to spacing the axial position of spacing ring 43, the external diameter of spacing ring 43 has certain clearance with the internal diameter of elasticity jack catch 7, second spring 42 sets up between thread fixing ring 41 and spacing ring 43 so that elasticity jack catch 7 moves along the axial and elastic recovery.

Referring to fig. 1 and 2, a biconical surface 8-2 is arranged at the outer edge of the head of the mandrel 8, as shown in the figure, the biconical surface 8-2 comprises a middle top end and conical surfaces positioned at two sides of the top end, a plurality of diameter-protecting strips 32 and a plurality of first alloy sheets 31 are uniformly arranged on the conical surface at the outer side of the top end and used for cutting burrs and the like at a broken drill rod, and an inner hexagonal hole is formed in the central axis core of the end surface of the head of the mandrel 8.

Referring to fig. 4, an elastic claw piece 7-1 covering the conical surface on the inner side of the top end of the mandrel is arranged on the elastic claw 7, a plurality of barbs 7-2 are arranged on the elastic claw piece 7-1, and the plurality of barbs 7-2 are axially arranged on the periphery of the elastic claw piece 7-1 at intervals, so that the fishing tool is connected with a broken drill rod more safely and reliably by the mutual cooperation of the barbs 7-2, the double conical surfaces, the gauge protection strips 32 and the first alloy pieces 31 when the elastic claw piece 7-1 is stretched; therefore, the fishing tool can also be used for fishing the drilling tool and is more widely applicable.

Referring to fig. 1, the spiral sleeve 2 includes spiral blades 21, 3 guide rods 22, a guide ring 24 and a plurality of second alloy pieces 23, the guide rods 22 are fixedly connected with the axial outer diameter of the spiral blades 21, the guide ring 24 is fixedly connected with the right end of the guide rods 22, and the inner diameter circumference of the guide ring 24 is uniformly provided with the plurality of second alloy pieces 23.

The invention also provides a fishing method of the internal clamping type drill rod fishing tool, which comprises the following steps:

the method comprises the following steps: firstly, an inner clamping type drill rod fishing tool is conveyed to a position where a drill rod is broken or falls, the central axis of an orifice fishing drill rod column is aligned with the central axis of a hole bottom broken drill rod column by using a V-shaped inclined plane at the front end of a spiral sleeve 2, the power head of a drilling machine rotates forwards, the burr edge of the broken drill rod end is ground by using a second alloy sheet 23 at the right end of the spiral sleeve 2, a gauge strip 32 at the right end of a mandrel 8 and a first alloy sheet 31, the power head of the drilling machine moves forwards, and the mandrel 8 of the inner clamping type drill rod fishing tool is conveyed into a hole of the hole bottom broken drill rod.

Step two: then, low-pressure water is introduced, under the action of the pressure, the inner valve core body 12 moves rightwards, the low-pressure water enters a piston cavity of the single-acting hydraulic cylinder 5 through a port P4-5 and a port A4-2 to push the thrust rod 6 to move rightwards, the second spring 42 is compressed under the action of the thrust force of the thrust rod 6, the elastic jaw assembly 40 moves rightwards along the axial direction, the elastic jaw piece 7-1 opens under the extrusion action of the conical surface 8-2 at the head end of the mandrel 8 to cut off the low-pressure water, under the reset action of the first spring 13, the port P4-5 of the high-low-pressure three-way valve 10 is closed, and the piston cavity of the single-acting hydraulic cylinder 5 is kept at low pressure all. Finally, slowly lifting the drill rod column at the orifice, wherein the barbs 7-2 on the elastic clamping claw sheets 7-1 are in contact with the step surface of the inner wall of the broken drill rod, and then the inner clamping type drill rod fishing tool clamps the step surface of the inner wall of the broken drill rod; and the power head of the drilling machine retreats to lift the drill rod column, so that the broken drill rod at the bottom of the hole can be salvaged.

Step three: if the drill rod column cannot be lifted after the inner clamping type drill rod fishing tool clamps the inner wall of the drill rod, the inner clamping type drill rod fishing tool needs to be separated from the drill rod column at the bottom of the hole, and the inner clamping type drill rod fishing tool is unlocked. Firstly, the power head advances for a certain distance, so that the barbs 7-2 on the elastic clamping claw sheets 7-1 are separated from the step surface of the inner wall of the drill rod, and a certain gap is reserved. Then high-pressure water is introduced, the outer valve core body 11 moves rightwards under the action of the pressure, so that the P port 4-5 of the high-low pressure three-way valve 10 is closed, the A port 4-2 of the high-low pressure three-way valve 10 is communicated with the T port 4-1, low-pressure water in the piston cavity of the single-acting hydraulic cylinder 5 flows into a drill hole through the T port 4-1, the drainage groove 4-4 and the drainage hole 1-2 in sequence, and the single-acting hydraulic cylinder 5 is reset. Under the action of the second spring 42 and the elastic force of the second spring 42, the elastic claw 7 moves leftwards along the axial direction, the elastic claw piece 7-1 contracts, the drill rod column is lifted, and the inner clamping type drill rod fishing tool is unlocked. And finally, cutting off the high-pressure water, and sequentially lifting the salvaging drill string to the outside of the hole.

Therefore, the fishing tool has the advantages of convenient use and high fishing success rate; still possess the unfreezing function, through high-low pressure change-over valve, can be fast with fishing tool and fracture drilling rod separation, prevent that the accident from worsening, reduce the loss.

It should be apparent that the foregoing description and illustrations are by way of example only and are not intended to limit the present disclosure, application or uses. While embodiments have been described in the embodiments and depicted in the drawings, the present invention is not limited to the particular examples illustrated by the drawings and described in the embodiments as the best mode presently contemplated for carrying out the teachings of the present invention, and the scope of the present invention will include any embodiments falling within the foregoing description and the appended claims.