CN116006096B - A kind of safety joint and using method thereof - Google Patents

Abstract

The invention relates to the technical field of drilling, in particular to a safety joint and a using method thereof. The safety joint includes a male joint and a female joint connected by a wide sawtooth thread, and a first sealing mechanism is embedded in the lower abutment of the male joint and the female joint, and the first sealing mechanism includes a first axial compensator. A first graphite sealing ring is provided on the upper end surface of an axial compensator, and a second graphite sealing ring is provided on the lower end surface, and the first axial compensator can expand and contract axially. The invention uses a graphite sealing ring with good thermal stability for sealing, and is matched with an axial compensation part capable of compensating the axial gap, which improves the sealing stability of the safety joint under high and low temperature alternating working conditions, and fully meets the requirements of dry hot rock well drilling Process requirements.

Description

A kind of safety joint and using method thereof

technical field

The invention relates to the technical field of drilling, in particular to a safety joint and a using method thereof.

Background technique

In the drilling process of dry and hot rock wells, the safety joint is a safety tool for disengaging and docking of the downhole pipe string. Disengage, thereby reducing the risk of operation, reducing the workload and improving the safety of operation. Commonly used safety joints mainly include shear nail type and zigzag buckle type.

Application number CN201220356121.6 discloses a zigzag thread safety joint, including a female joint, a male joint, an upper sealing ring and a lower sealing ring. The female joint is connected to the male joint through a zigzag thread, and a There are an upper sealing ring and a lower sealing ring, the upper part of the female joint is provided with connecting threads, and the lower part of the male joint is provided with connecting threads. The safety joint has a reasonable structural design and is easy to use. However, the safety joint is designed for cold recovery wells. Both the upper and lower sealing rings use conventional rubber sealing rings, which will fail under high temperature conditions and cannot meet the requirements of hot dry rock drilling. The working conditions of 200-300°C will affect the production; in addition, in dry hot rock wells, the metal safety joints will expand with heat and contract with the alternation of high and low temperatures, and the axial gap between the male joint and the female joint will decrease. Changes will affect the sealing effect.

Contents of the invention

In order to solve at least one of the above-mentioned technical problems, the present invention provides a safety joint, which includes a male joint and a female joint connected by a wide sawtooth thread, and a first sealing mechanism is embedded in the lower abutment of the male joint and the female joint. The first sealing mechanism includes a first axial compensator, the upper end surface of the first axial compensator is provided with a first graphite seal ring, and the lower end surface is provided with a second graphite seal ring, and the first axial compensator is Capable of axial expansion and contraction.

Preferably, the male joint includes an annular first lower connection end and a first upper connection end, the inner ring surface of the first lower connection end is provided with a connecting thread, and the upper end surface is provided with a first annular groove, the The outer ring surface of the first upper connection end is provided with a serrated thread portion, and the upper end surface is provided with a second annular groove, and a high-temperature resistant sealing ring is embedded above the outer wall of the male joint; the female joint includes a circular second lower The connecting end and the second upper connecting end, the inner ring surface of the second lower connecting end is provided with a serrated thread groove corresponding to the serrated thread part, the lower end surface is provided with a first insertion groove, and the upper end surface is provided with an annular sealing slide groove, and the outer ring surface of the second upper connecting end is provided with connecting threads.

Preferably, the first axial compensator includes a heat-expandable member that is elongated by heat, the upper end surface of the heat-expandable member is connected to the first lifting ring, and the lower end surface is connected to the second lifting ring, and the first graphite sealing ring and Each of the second graphite sealing rings has an L-shaped section, the first graphite sealing ring is embedded in the first embedding groove of the lower abutment of the female joint, and the second graphite sealing ring is embedded in the lower abutment of the male joint in the first annular groove.

Preferably, the heat-extensible member includes a plurality of piston cylinders distributed equidistantly around the circumference, and a first stop protrusion and a second stop protrusion are arranged axially at intervals in the piston cylinder, and the first stop protrusion A first piston is provided above, the first piston is connected to the first piston rod, the first piston rod is connected to the first lifting ring, the first piston rod is sleeved with a first spring, and the second A second piston is provided below the limit protrusion, the second piston is connected to the second piston rod, the second piston rod is connected to the second lifting ring, and the second piston rod is sleeved with a second spring, so A thermal expansion fluid is provided between the first piston and the second piston.

Preferably, a second sealing mechanism is embedded at the upper abutment of the male joint and the female joint, and the second sealing mechanism includes a third graphite sealing ring and a fourth graphite sealing ring coaxially arranged at intervals. The upper end surfaces of the graphite sealing ring and the fourth graphite sealing ring are provided with an axially expandable second axial compensator.

Preferably, the second axial compensator includes a sealing compression ring, the lower end surface of the sealing compression ring presses the third graphite sealing ring and the fourth graphite sealing ring, the upper end surface is connected to an annular piston, and the annular piston Slidingly arranged in the sealing chute on the female joint, the sealing cavity formed by the two contains the expansion fluid, and one end of a plurality of memory springs arranged equidistantly on the circumference is fixed in the sealing chute, and the other end is connected to the sealing chute. Annular piston; the annular piston has a T-shaped cross-section, and sequentially includes a first sealing part, a second sealing part and a sliding part from top to bottom, the first sealing part and the second sealing part are arranged at intervals, and the sealing slide The groove includes an upper chute and a lower chute, and the first sealing part and the second sealing part seal and slide in the upper chute.

Preferably, the third graphite sealing ring and the fourth graphite sealing ring are arranged in the second annular groove at the abutting part of the male joint, and both the third graphite sealing ring and the fourth graphite sealing ring have a diamond-shaped cross section , the upper end surface and the lower end surface of the two together form a V-shaped structure, the lower end surface of the sealing pressure ring has a corresponding V-shaped section, and the second annular groove also has a corresponding V-shaped section.

Preferably, the upper end surface of the sealing pressure ring is fixedly provided with a connecting ring, the upper end surface of the connecting ring is connected to the annular piston, the first memory metal ring and the first tensioning mechanism are provided on the outside, and the second tensioning mechanism is provided on the inside. The memory metal ring and the second tensioning mechanism, the outer groove wall of the sliding groove is provided with a second embedding groove, the inner groove wall is provided with a third embedding groove, the first memory metal ring is embedded in the second embedding groove, The second memory metal ring is inserted into the third insertion groove after being deformed by heat, and escapes from the third insertion groove after being deformed by heat.

Preferably, the first tensioning mechanism includes a first lower fixed ring and a first upper fixed ring, the lower end of the first upper fixed ring is connected to a third spring, and the lower end of the third spring is connected to the first movable ring , the first memory metal ring is clamped by the first lower fixed ring and the first movable ring, the second tensioning mechanism includes a second lower fixed ring and a second upper fixed ring, and the second upper fixed ring The lower end surface of the ring is connected to the fourth spring, the lower end of the fourth spring is connected to the second movable ring, and the second memory metal ring is clamped by the second lower fixed ring and the second movable ring.

The invention provides a method for using a safety joint, comprising the following steps:

Step S100, embed the first sealing mechanism in the lower abutment of the male joint and the female joint, and embed the second sealing mechanism in the upper abutment of the male joint and the female joint; connect the male joint to the downstream pipe string, and the female joint Run into the predetermined position in the well after connecting the upstream pipe string;

Step S200, when drilling in dry hot rock wells, the safety joint made of metal is heated and axially elongated, the axial gap between the male joint and the female joint increases, the first sealing mechanism and the second sealing mechanism are axially elongated, and the compensation Due to the axial gap generated by high temperature, the first sealing mechanism and the second sealing mechanism are always in close contact with the male joint and the female joint to improve the sealing effect;

Step S300 , when tripping is required, torque force is provided for the upstream pipe string of the female joint, the female joint is rotated and disengaged from the male joint, and the male joint and the downstream pipe string stay downhole.

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

1. The first sealing mechanism is embedded in the lower abutment of the male joint and the female joint. The first sealing mechanism adopts the first axial compensation part for axial compensation, and adopts a graphite ring with good thermal stability to form an axial double sealing structure. Can fully guarantee the sealing effect at high temperature;

2. The first axial compensation part is equipped with a thermal expansion part that can respond to temperature changes. The expansion fluid is used as the driving source of thermal compensation. The thermal response effect of the expansion fluid is good, and the driving force provided during expansion is high. direction compensation, and can provide enough expansion force to compress the first graphite sealing ring and the second graphite sealing ring; the first lifting ring and the second lifting ring push the first graphite sealing ring and the second graphite sealing ring up and down, which can Make the first graphite sealing ring and the second graphite sealing ring evenly stressed, fully protect them from damage;

3. A second sealing mechanism is embedded in the upper abutment of the male joint and the female joint. The second sealing mechanism adopts the second axial compensator for axial compensation, and adopts a graphite ring with good thermal stability to form a radial double sealing structure. The first sealing mechanism cooperates with each other to further improve the sealing effect;

4. The annular piston of the second sealing mechanism has a first sealing part and a second sealing part, forming an axial double sealing structure to improve the sealing performance of the piston ring;

5. The memory spring and expansion fluid of the second sealing mechanism can respond to temperature changes, lift the annular piston at low temperature, press down the annular piston at high temperature, and instantly compensate and adjust the axial gap between the male joint and the female joint;

6. The first memory metal ring and the second memory metal ring of the second sealing mechanism can lock or unlock the annular piston according to the temperature change to meet the use requirements under different temperatures;

7. Both the third graphite sealing ring and the fourth graphite sealing ring have a diamond-shaped cross section, and the second annular groove and the sealing pressure ring respectively form a V-shaped sealing structure with the two, further improving the sealing effect;

To sum up, the present invention uses a graphite sealing ring with good thermal stability for sealing, and is equipped with an axial compensation member capable of compensating the axial gap, which improves the sealing stability of the safety joint under alternating high and low temperature conditions, and fully meets the Technological requirements for hot dry rock well drilling.

Description of drawings

Fig. 1 is a structural representation of the present invention;

Fig. 2 is a partial enlarged view of A in Fig. 1;

Fig. 3 is a three-dimensional structural sectional view of a male joint;

Fig. 4 is a three-dimensional structural sectional view of a female joint;

Fig. 5 is a three-dimensional structural cross-sectional view of the first sealing mechanism;

Fig. 6 is a three-dimensional structural cross-sectional view of the thermal expansion member;

Fig. 7 is a sectional view of the three-dimensional structure of the second sealing mechanism.

Explanation of reference signs:

1. Male joint, 11. First lower connection end, 12. First upper connection end, 13. First annular groove, 14. Serrated thread part, 15. Second annular groove, 2. Female joint, 21. Second Lower connection end, 22, second upper connection end, 23, serrated thread groove, 24, first insertion groove, 25, sealing chute, 251, upper chute, 252, lower chute, 2521, second insertion groove, 2522 , the third embedding groove, 3, the first sealing mechanism, 31, the first axial compensation member, 311, the thermal expansion member, 3111, the piston cylinder, 3112, the first limit protrusion, 3113, the second limit protrusion , 3114, the first piston, 3115, the first piston rod, 3116, the first spring, 3117, the second piston, 3118, the second piston rod, 3119, the second spring, 312, the first lifting ring, 313, the second Lifting ring, 32, first graphite sealing ring, 33, second graphite sealing ring, 4, high temperature resistant sealing ring, 5, second sealing mechanism, 51, third graphite sealing ring, 52, fourth graphite sealing ring, 53 , second axial compensator, 531, sealing pressure ring, 532, annular piston, 5321, first sealing part, 5322, second sealing part, 5323, sliding part, 533, memory spring, 534, connecting ring, 535, The first memory metal ring, 536, the first tensioning mechanism, 5361, the first lower fixed ring, 5362, the first movable ring, 5363, the third spring, 5364, the first upper fixed ring, 537, the second memory metal ring , 538, the second tensioning mechanism, 5381, the second lower fixed ring, 5382, the second movable ring, 5383, the fourth spring, 5384, the second upper fixed ring.

Detailed ways

Describe the specific embodiment of the present invention below in conjunction with accompanying drawing and embodiment:

It should be noted that the structures, proportions, sizes, etc. shown in the drawings attached to this specification are only used to match the content disclosed in the specification, for those who are familiar with this technology to understand and read, and are not used to limit the implementation of the present invention Any modification of structure, change of proportional relationship or adjustment of size shall fall within the range covered by the technical content disclosed in the present invention without affecting the effect and purpose of the present invention. within range.

At the same time, terms such as "upper", "lower", "left", "right", "middle" and "one" quoted in this specification are only for the convenience of description and are not used to limit this specification. The practicable scope of the invention and the change or adjustment of its relative relationship shall also be regarded as the practicable scope of the present invention without any substantial change in the technical content.

Example 1

With reference to accompanying drawings 1 to 7, this embodiment provides a safety joint, including a male joint 1 and a female joint 2 connected by a wide sawtooth thread. A first sealing mechanism 3 is provided, and the first sealing mechanism 3 includes a first axial compensator 31, the upper end surface of the first axial compensator 31 is provided with a first graphite sealing ring 32, and the lower end surface is provided with a second The graphite sealing ring 33, the first axial compensator 31 can expand and contract axially. In the above technical solution, the first graphite sealing ring 32 and the second graphite sealing ring 33 of the first sealing mechanism 3 form an axial double sealing structure, and the upper end surface and the outer ring surface of the first graphite sealing ring 32 closely abut the female joint 2 , the inner ring surface tightly abuts the male joint 1, the lower end surface and the inner ring surface of the second graphite sealing ring 33 closely abut the male joint 1, and the outer ring surface closely abuts the female joint 2, further improving the performance of the first sealing mechanism 3 Thermal stability and sealing effect, the first axial compensator 31 can expand and contract axially, and fully compress the first graphite sealing ring 32 and the second graphite sealing ring 33 . The first axial compensator 31 can be a conventional elastic metal element such as a circular spring or the like.

In a specific structure, the male joint 1 includes an annular first lower connecting end 11 and a first upper connecting end 12, the inner ring surface of the first lower connecting end 11 is provided with connecting threads, and the upper end surface is provided with There is a first annular groove 13, the outer ring surface of the first upper connection end 12 is provided with a serrated thread portion 14, and the upper end surface is provided with a second annular groove 15, and a high temperature resistant seal is embedded above the outer wall of the male joint 1 Ring 4; the female joint 2 includes a circular second lower connection end 21 and a second upper connection end 22, and the inner ring surface of the second lower connection end 21 is provided with serrations corresponding to the serrated thread portion 14 The thread groove 23 has a first embedded groove 24 on the lower end surface, an annular sealing sliding groove 25 on the upper end surface, and a connecting thread on the outer ring surface of the second upper connecting end 22 . In the above technical solution, the lower abutment of the male joint 1 and the female joint 2 is the upper end surface of the first lower connection end 11 of the male joint 1 and the lower end surface of the second lower connection end 21 of the female joint 2; the first sealing The mechanism 3 is embedded in the annular space jointly formed by the first annular groove 13 and the first embedding groove 24 . The high temperature resistant sealing ring 4 is preferably made of fluorine rubber, which acts as an auxiliary seal. The thread direction is configured according to common knowledge in the field, that is, the direction of rotation of the connecting thread of the male connector 1 and the connecting thread of the female connector 2 is opposite to that of the serrated thread portion 14 of the male connector 1 .

The working principle and working process of this embodiment are as follows: the first sealing mechanism 3 is embedded in the lower abutment of the male joint 1 and the female joint 2, the male joint 1 is connected to the downstream pipe string, and the female joint 2 is connected to the upstream pipe string. Run into the predetermined position in the well; when drilling in dry hot rock wells, the safety joint made of metal will elongate axially when heated, the axial gap between the male joint 1 and the female joint 2 will increase, and the first sealing mechanism 3 will elongate axially , to compensate for the axial clearance caused by high temperature, so that the first graphite sealing ring 32 and the second graphite sealing ring 33 are always in close contact with the male joint 1 and the female joint 2 to improve the sealing effect; The upstream pipe string of the joint 2 provides torque force, the female joint 2 rotates and disengages from the male joint 1, and the male joint 1 and the downstream pipe string stay downhole.

In this embodiment, the first sealing mechanism 3 adopts the first axial compensator 31 for axial compensation, and adopts a thermally stable graphite ring to form an axial double sealing structure, which can fully guarantee the sealing effect at high temperature.

Example 2

In combination with accompanying drawings 1 to 7, this embodiment provides a safety joint. On the basis of Embodiment 1, a special structural design is carried out on the first axial compensator 31, so that it has a thermal expansion and contraction function, which can further improve the compensation effect , the specific technical scheme is as follows,

The first axial compensator 31 includes a heat-expandable member 311 that is elongated by heat. The upper end surface of the heat-expandable member 311 is connected to the first lifting ring 312, and the lower end surface is connected to the second lifting ring 313. The first graphite seal Both the ring 32 and the second graphite sealing ring 33 have an L-shaped section, the first graphite sealing ring 32 is embedded in the first insertion groove 24 at the lower abutment of the female joint 2, and the second graphite sealing ring 33 is embedded in In the first annular groove 13 at the lower abutment of the male joint 1 . In the above technical solution, the heat-expandable member 311 with heat-expandable function is adopted. Compared with the conventional elastic member, the heat-expandable member 311 can respond to temperature changes, provide suitable pressing force at normal temperature, and elongate at high temperature. The axial clearance can provide stronger pressing force at the same time, and fully guarantee the sealing effect.

In a specific structure, the thermal expansion member 311 includes a plurality of piston cylinders 3111 equidistantly distributed around the circumference, and the piston cylinders 3111 are provided with a first stop protrusion 3112 and a second stop protrusion 3113 at intervals in the axial direction. , a first piston 3114 is provided above the first limiting protrusion 3112, the first piston 3114 is connected to a first piston rod 3115, and the first piston rod 3115 is connected to the first lifting ring 312, and the first piston rod 3115 is connected to the first lifting ring 312, and the first A piston rod 3115 is sleeved with a first spring 3116, a second piston 3117 is provided below the second limiting protrusion 3113, the second piston 3117 is connected to a second piston rod 3118, and the second piston rod 3118 is connected to The second lifting ring 313, the second piston rod 3118 is sleeved with a second spring 3119, and a thermal expansion fluid is provided between the first piston 3114 and the second piston 3117. In the above technical solution, the expansion fluid is used as the driving source for thermal compensation. The thermal response of the expansion fluid is good, and the driving force provided during expansion is high. It can not only quickly perform axial compensation, but also provide sufficient expansion force for the first graphite The sealing ring 32 and the second graphite sealing ring 33 are compressed; the first lifting ring 312 and the second lifting ring 313 promote the lifting of the first graphite sealing ring 32 and the second graphite sealing ring 33, so that the first graphite sealing ring 32 and the second graphite sealing ring can be lifted. The second graphite sealing ring 33 is evenly stressed, fully protecting it from damage.

The working principle and working process of this embodiment are as follows: in the initial state, the first sealing mechanism 3 is embedded in the lower abutment of the male joint 1 and the female joint 2; when the temperature is high, the metal safety joint is heated and stretched axially, The gap between the abutment of the male joint 1 and the female joint 2 increases, the expansion fluid expands when heated, and the volume increases, pushing the first piston rod 3115 and the second piston rod 3118 to elongate, passing through the first lifting ring 312 and the second lifting ring 313 Compress the first graphite sealing ring 32 and the second graphite sealing ring 33 so that they closely fit the male joint 1 and the female joint 2 to improve the sealing effect; The gap at the junction decreases, the expansion liquid cools and shrinks, and the volume decreases, the first piston rod 3115 and the second piston rod 3118 reset, and the first graphite sealing ring 32 and the second graphite sealing ring 33 reset accordingly, and the original sealing state is restored .

Example 3

In combination with accompanying drawings 1 to 7, this embodiment provides a safety joint. On the basis of Embodiment 1 or Embodiment 2, a second sealing mechanism 5 is added to further improve the sealing effect. The specific technical scheme is as follows:

A second sealing mechanism 5 is embedded in the upper abutment of the male joint 1 and the female joint 2, and the second sealing mechanism 5 includes a third graphite sealing ring 51 and a fourth graphite sealing ring 52 coaxially arranged at intervals. The upper end surfaces of the third graphite sealing ring 51 and the fourth graphite sealing ring 52 are provided with an axially expandable second axial compensator 53 . In the above technical solution, the third graphite sealing ring 51 and the fourth graphite sealing ring 52 form a radial double sealing structure, the outer ring wall of the third graphite sealing ring 51 closely abuts the female joint 2, and the lower end surface closely abuts the male joint 1 , the inner ring wall and the lower end surface of the fourth graphite sealing ring 52 are tightly abutted against the male joint 1, and the second axial compensator 53 can be axially expanded and contracted to fully compress the third graphite sealing ring 51 and the fourth graphite sealing ring 52 . The axial double seal structure of the first sealing mechanism 3 and the radial double seal structure of the second sealing mechanism 5 cooperate with each other to further improve the sealing effect.

In a specific structure, the second axial compensator 53 includes a sealing pressure ring 531, the lower end surface of the sealing pressure ring 531 presses the third graphite sealing ring 51 and the fourth graphite sealing ring 52, and the upper end surface Connect the annular piston 532, the annular piston 532 is slidably arranged in the sealing chute 25 on the female joint 2, the sealing cavity formed by the two contains the expansion fluid, and one end of a plurality of circumferentially equidistantly arranged memory springs 533 is fixed In the sealing chute 25, the other end is connected to the annular piston 532; the annular piston 532 has a T-shaped cross-section and includes a first sealing part 5321, a second sealing part 5322 and a sliding part 5323 from top to bottom. , the first sealing part 5321 and the second sealing part 5322 are arranged at intervals, the sealing chute 25 includes an upper chute 251 and a lower chute 252, the first sealing part 5321 and the second sealing part 5322 are on the upper Seal sliding in the chute 251 . In the above technical solution, the expansion fluid is used as the driving source of thermal compensation, and its function and principle are the same as before. The first sealing portion 5321 and the second sealing portion 5322 of the annular piston 532 form an axial double sealing structure, which can further improve the sealing performance of the annular piston 532 . When the memory spring 533 is below the deformation temperature, the diameter is large and the length is short, and it plays a role in pulling the ring piston 532, and the ring piston 532 is lifted; when the temperature is above the deformation temperature, the diameter is small and the length is long, and it pushes the ring piston 532, and the ring piston 532 is lifted. Piston 532 is depressed.

In a specific structure, the third graphite sealing ring 51 and the fourth graphite sealing ring 52 are arranged in the second annular groove 15 at the abutment on the male joint 1, and the third graphite sealing ring 51 and the fourth graphite sealing ring 51 The four graphite sealing rings 52 all have a diamond-shaped section, and the upper and lower end surfaces of both form a V-shaped structure together. The lower end surface of the sealing pressure ring 531 has a corresponding V-shaped section, and the second annular groove 15 also has a corresponding V-shaped section. V-shaped section. In the above technical solution, both the third graphite sealing ring 51 and the fourth graphite sealing ring 52 have a diamond-shaped cross section, and the second annular groove 15 and the sealing pressure ring 531 respectively form a V-shaped sealing structure with the two, further improving the sealing effect.

In a specific structure, the upper end surface of the sealing pressure ring 531 is fixed with a connecting ring 534, the upper end surface of the connecting ring 534 is connected to the annular piston 532, and the first memory metal ring 535 and the first sheet are arranged on the outside. The tightening mechanism 536 is provided with a second memory metal ring 537 and a second tensioning mechanism 538 on the inner side. The outer groove wall of the sliding groove 252 is provided with a second insertion groove 2521, and the inner groove wall is provided with a third insertion groove 2522. The first memory metal ring 535 is inserted into the second insertion groove 2521, and comes out of the second insertion groove 2521 after being deformed by heat; Describe the third embedding groove 2522. In the above technical solution, the first memory metal ring 535, the second memory metal ring 537 and the second embedding groove 2521 and the third embedding groove 2522 form a locking structure; when the deformation temperature is below, the outer diameter of the first memory metal ring 535 is larger than The outer diameter of the sliding groove 252 is embedded in the second insertion groove 2521, the inner diameter of the second memory metal ring 537 is smaller than the inner diameter of the sliding groove 252, embedded in the third insertion groove 2522, the sealing pressure ring 531 is locked, and when the deformation temperature is above, The outer diameter of the first memory metal ring 535 is less than or equal to the outer diameter of the sliding groove 252, and escapes from the second insertion groove 2521; the inner diameter of the second memory metal ring 537 is greater than or equal to the inner diameter of the sliding groove 252, and escapes from the third insertion groove 2522. , the sealing pressure ring 531 is unlocked and can move freely in the axial direction. The deformation temperature of the first memory metal ring 535 and the second memory metal ring 537 is lower than the thermal expansion temperature of the expansion fluid and the deformation temperature of the memory spring 533 .

In a specific structure, the first tensioning mechanism 536 includes a first lower fixing ring 5361 and a first upper fixing ring 5364, the lower end surface of the first upper fixing ring 5364 is connected to a third spring 5363, and the third spring 5363 The lower end of the spring is connected to the first movable ring 5362, the first memory metal ring 535 is clamped by the first lower fixed ring 5361 and the first movable ring 5362, and the second tensioning mechanism 538 includes a second lower fixed ring 5381 and the second upper fixed ring 5384, the lower end of the second upper fixed ring 5384 is connected to the fourth spring 5383, the lower end of the fourth spring 5383 is connected to the second movable ring 5382, and the second memory metal ring 537 is The second lower fixed ring 5381 is clamped by the second movable ring 5382 . In the above technical solution, the first tensioning mechanism 536 and the second tensioning mechanism 538 can tightly clamp the first memory metal ring 535 and the second memory metal ring 537, and compensate the first memory metal ring 535 and the second memory metal ring 537 The axial displacement during deformation enables the first memory metal ring 535 and the second memory metal ring 537 to be stably inserted into or out of the second insertion groove 2521 and the third insertion groove 2522 .

The working principle and working process of this embodiment are as follows: in the initial state, the second sealing mechanism 5 is embedded in the upper abutment of the male joint 1 and the female joint 2; at high temperature, when the temperature rises to the first memory metal ring 535 and the deformation temperature of the second memory metal ring 537, the first memory metal ring 535 and the second memory metal ring 537 deform and escape from the second insertion groove 2521 and the third insertion groove 2522, the sealing pressure ring 531 is unlocked, and the temperature continues to rise to The expansion liquid and the deformation temperature of the memory spring 533, the expansion liquid expands, the volume increases, and the memory spring 533 elongates, and the two jointly push the sealing pressure ring 531 to move down, so that the third graphite sealing ring 51 and the fourth graphite sealing ring 52 are tightly sealed. Butt against the male joint 1 and the female joint 2, compensate the gap generated by the safety joint after heating, and improve the sealing effect; after the mining is completed, the temperature drops, and when it falls below the deformation temperature of the expansion fluid and the memory spring 533, the expansion fluid shrinks and the memory spring 533 The spring 533 is shortened, and the two lift the sealing pressure ring 531 to the initial position together. When the temperature continues to drop below the deformation temperature of the first memory metal ring 535 and the second memory metal ring 537, the first memory metal ring 535 and the second memory metal ring The memory metal ring 537 deforms and embeds into the second embedding groove 2521 and the third embedding groove 2522 , and recovers the locked state of the sealing pressure ring 531 .

Example 4

With reference to accompanying drawings 1 to 7, this embodiment provides a method for using a safety joint, which is characterized in that it includes the following steps:

Step S100, embedding the first sealing mechanism 3 in the lower abutment of the male joint 1 and the female joint 2, and embedding the second sealing mechanism 5 in the upper abutment of the male joint 1 and the female joint 2; Connect the downstream pipe string, and the female joint 2 is connected to the upstream pipe string and lowered into the predetermined position in the well;

Step S200, during drilling of dry hot rock wells, the safety joint made of metal is heated and axially elongated, the axial gap between the male joint 1 and the female joint 2 increases, and the first sealing mechanism 3 and the second sealing mechanism 5 axially expand. Elongate to compensate for the axial gap caused by high temperature, so that the first sealing mechanism 3 and the second sealing mechanism 5 are always in close contact with the male joint 1 and the female joint 2 to improve the sealing effect;

Step S300 , when tripping is required, torque force is provided for the upstream pipe string of the female joint 2 , the female joint 2 rotates and disengages from the male joint 1 , and the male joint 1 and the downstream pipe string stay downhole.

The above-mentioned embodiment is a preferred embodiment of the present invention, but the embodiment of the present invention is not limited by the above-mentioned embodiment, and any other changes, modifications, substitutions, combinations, Simplification should be equivalent replacement methods, and all are included in the protection scope of the present invention.

Claims (10)

1. The utility model provides a safety joint, includes wide sawtooth threaded connection's public joint (1) and female joint (2), its characterized in that, first sealing mechanism (3) are inlayed in the lower butt department of public joint (1) and female joint (2), first sealing mechanism (3) are including first axial compensation piece (31), the up end of first axial compensation piece (31) is equipped with first graphite sealing ring (32), and the lower terminal surface is equipped with second graphite sealing ring (33), first axial compensation piece (31) can axial expansion.

2. The safety joint according to claim 1, wherein the male joint (1) comprises a circular first lower connecting end (11) and a first upper connecting end (12), the inner annular surface of the first lower connecting end (11) is provided with connecting threads, the upper end surface is provided with a first annular groove (13), the outer annular surface of the first upper connecting end (12) is provided with a sawtooth threaded part (14), the upper end surface is provided with a second annular groove (15), and a high-temperature-resistant sealing ring (4) is embedded above the outer side wall of the male joint (1); the female joint (2) comprises a circular second lower connecting end (21) and a second upper connecting end (22), a saw tooth thread groove (23) corresponding to the saw tooth thread part (14) is formed in the inner annular surface of the second lower connecting end (21), a first embedded groove (24) is formed in the lower end surface, an annular sealing sliding groove (25) is formed in the upper end surface, and connecting threads are formed in the outer annular surface of the second upper connecting end (22).

3. A safety joint according to claim 2, wherein the first axial compensation element (31) comprises a thermally elongated thermal expansion element (311), the upper end surface of the thermal expansion element (311) is connected with a first lifting ring (312), the lower end surface is connected with a second lifting ring (313), the first graphite sealing ring (32) and the second graphite sealing ring (33) both have L-shaped cross sections, the first graphite sealing ring (32) is embedded in a first embedding groove (24) at the lower butt of the female joint (2), and the second graphite sealing ring (33) is embedded in a first annular groove (13) at the lower butt of the male joint (1).

4. A safety joint according to claim 3, wherein the thermal expansion member (311) comprises a plurality of circumferentially equidistant piston cylinders (3111), first spacing protrusions (3112) and second spacing protrusions (3113) are axially arranged at intervals in the piston cylinders (3111), first pistons (3114) are arranged above the first spacing protrusions (3112), the first pistons (3114) are connected with first piston rods (3115), the first piston rods (3115) are connected with first lifting rings (312), first springs (3116) are sleeved on the first piston rods (3115), second pistons (3117) are arranged below the second spacing protrusions (3113), the second pistons (3117) are connected with second piston rods (3118), second pistons (3118) are connected with second lifting rings (313), second springs (3119) are sleeved on the second piston rods (3118), and thermal expansion liquid is arranged between the first pistons (3114) and the second pistons (3117).

5. The safety joint according to claim 4, wherein a second sealing mechanism (5) is embedded at the upper abutting part of the male joint (1) and the female joint (2), the second sealing mechanism (5) comprises a third graphite sealing ring (51) and a fourth graphite sealing ring (52) which are coaxially arranged at intervals, and upper end surfaces of the third graphite sealing ring (51) and the fourth graphite sealing ring (52) are provided with axial telescopic second axial compensation pieces (53).

6. The safety joint according to claim 5, wherein the second axial compensation member (53) comprises a sealing compression ring (531), the lower end surface of the sealing compression ring (531) compresses the third graphite sealing ring (51) and the fourth graphite sealing ring (52), the upper end surface is connected with an annular piston (532), the annular piston (532) is slidably arranged in a sealing chute (25) on the female joint (2), an expansion liquid is contained in a sealing cavity formed by the sealing compression ring and the annular piston (532), one ends of a plurality of memory springs (533) which are circumferentially and equidistantly arranged are fixed in the sealing chute (25), and the other ends of the memory springs are connected with the annular piston (532); annular piston (532) are T style of calligraphy cross-section, from top to bottom includes first sealing portion (5321), second sealing portion (5322) and sliding part (5323) in proper order, first sealing portion (5321) and second sealing portion (5322) interval set up, sealed spout (25) include spout (251) and lower spout (252), first sealing portion (5321) and second sealing portion (5322) are in go up spout (251) internal seal slip.

7. The safety joint according to claim 6, wherein the third graphite sealing ring (51) and the fourth graphite sealing ring (52) are arranged in a second annular groove (15) at the abutting position on the male joint (1), the third graphite sealing ring (51) and the fourth graphite sealing ring (52) are both provided with diamond-shaped cross sections, the upper end face and the lower end face of the third graphite sealing ring and the fourth graphite sealing ring together form a V-shaped structure, the lower end face of the sealing compression ring (531) is provided with a corresponding V-shaped cross section, and the second annular groove (15) is also provided with a corresponding V-shaped cross section.

8. The safety joint according to claim 7, wherein a connecting ring (534) is fixedly arranged on an upper end surface of the sealing compression ring (531), the upper end surface of the connecting ring (534) is connected with the annular piston (532), a first memory metal ring (535) and a first tensioning mechanism (536) are arranged on the outer side, a second memory metal ring (537) and a second tensioning mechanism (538) are arranged on the inner side, a second embedding groove (2521) is arranged on an outer groove wall of the lower sliding groove (252), a third embedding groove (2522) is arranged on an inner groove wall, the first memory metal ring (535) is embedded in the second embedding groove (2521), the second embedding groove (2521) is separated after being deformed by heating, the second memory metal ring (537) is embedded in the third embedding groove (2522), and the third embedding groove (2522) is separated after being deformed by heating.

9. The safety joint according to claim 8, wherein the first tensioning mechanism (536) comprises a first lower fixed ring (5361) and a first upper fixed ring (5364), a lower end surface of the first upper fixed ring (5364) is connected to a third spring (5363), a lower end of the third spring is connected to a first movable ring (5362), the first memory metal ring (535) is clamped by the first lower fixed ring (5361) and the first movable ring (5362), the second tensioning mechanism (538) comprises a second lower fixed ring (5381) and a second upper fixed ring (5384), a lower end surface of the second upper fixed ring (5384) is connected to a fourth spring (5383), a lower end of the fourth spring (5383) is connected to a second movable ring (5382), and the second memory metal ring (537) is clamped by the second lower fixed ring (5381) and the second movable ring (5382).

10. The method of using a safety joint according to claim 9, comprising the steps of:

step S100, embedding a first sealing mechanism (3) at the lower abutting position of the male connector (1) and the female connector (2), and embedding a second sealing mechanism (5) at the upper abutting position of the male connector (1) and the female connector (2); connecting the male connector (1) with the downstream pipe string, and connecting the female connector (2) with the upstream pipe string and then putting the pipe string into a preset position in the well;

step S200, when a dry-hot rock well is drilled, a safety joint made of metal is heated and axially stretched, an axial gap at the abutting position of a male joint (1) and a female joint (2) is increased, a first sealing mechanism (3) and a second sealing mechanism (5) are axially stretched, the axial gap generated by high temperature is compensated, the first sealing mechanism (3) and the second sealing mechanism (5) are always tightly abutted against the male joint (1) and the female joint (2), and the sealing effect is improved;

and step S300, when the tripping is required, a torque force is provided for the upstream pipe string of the female connector (2), the female connector (2) rotates to be disconnected with the male connector (1), and the male connector (1) and the downstream pipe string are left in the pit.

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