A petroleum drilling leak stopping structure

Abstract

The application discloses a petroleum drilling leakage stopping structure, which comprises a drilling well and a drill string in the drilling well, a mandrel capable of moving up and down is arranged in the drill string, a first circulating hole is symmetrically arranged on the circumference of the drill string, a second circulating hole is arranged on the circumference of the mandrel, the first circulating hole and the second circulating hole are arranged in a dislocation mode in a normal state, when the mandrel moves downwards and the first circulating hole corresponds to the second circulating hole, leakage stopping mud flows out of the drilling well and flows to a leakage seam, a ball catcher is arranged at the bottom end of the mandrel, and the ball catcher is communicated with the drilling well.

Description

Technical Field

[0001] This invention relates to the field of oil well plugging technology, and more particularly to an oil well plugging structure. Background Technology

[0002] Well leakage is one of the most frequent downhole problems in oil drilling projects. Well leakage not only wastes a lot of materials and delays the drilling cycle, but in severe cases it may also cause blowouts and overflows, resulting in serious economic losses and safety hazards. Once well leakage is discovered, the leaking part will be plugged in time to prevent the leakage from expanding.

[0003] Chinese invention patent CN115749671B discloses a drilling constant pressure loop plugging tool and method. The plugging tool includes a central tube, on the outer wall of which, from top to bottom, are fitted a mounting mechanism, a rubber sleeve, a piston, a sealing ring, and a guide shoe. A cylinder liner is provided on the outer surface of the piston, which is located between the central tube and the cylinder liner. The upper end of the guide shoe is connected to the cylinder liner. An oil hole is provided on the central tube, and a drilling fluid flow channel is provided between the piston and the sealing ring, with the oil hole communicating with the drilling fluid flow channel. A valve body is provided inside the central tube, located below the oil hole. This invention solves the technical problem of ineffective plugging of lost circulation zones.

[0004] However, the above-mentioned plugging method uses upper and lower plugging balls for plugging, which cannot achieve automatic plugging by moving up and down. Furthermore, the plugging balls cannot be caught and captured in time after plugging, which can easily collide with the drill string during subsequent drilling, affecting the drilling route and increasing errors, making it inconvenient to use. Summary of the Invention

[0005] The purpose of this invention is to solve the above-mentioned problems by providing an oil well plugging structure that can effectively seal well leaks during use, is simple to operate, has high sealing efficiency, and allows for continued stable drilling after sealing, thus meeting the requirements of use.

[0006] To achieve the above objectives, the technical solution of the present invention is as follows: an oil well plugging structure, comprising a well and a drill string inside the well, wherein a mandrel capable of moving up and down is provided inside the drill string, a first circulation hole is symmetrically provided on the circumference of the drill string, and a second circulation hole is provided on the circumference of the mandrel. Under normal conditions, the first circulation hole and the second circulation hole are misaligned. When the mandrel moves downward so that the first circulation hole aligns with the second circulation hole, plugging mud flows out into the well and flows toward the leak. A ball catcher is provided at the bottom end of the mandrel, and the ball catcher is connected to the well.

[0007] Preferably, the inner wall of the drill string is provided with a fixing ring, and a plurality of elastic fins are evenly provided below the fixing ring. The ends of the elastic fins are provided with locking hooks, and the bottom outer side of the locking hooks is provided with an arc-shaped ramp surface. The inner wall of the mandrel is provided with a first protrusion and a second protrusion. When the mandrel is locked, the locking hook is located between the first protrusion and the second protrusion. When the mandrel moves downward, the second protrusion abuts against the locking hook and causes the plurality of elastic fins to converge toward the axis. The outer side of the second protrusion is also provided with an arc-shaped ramp surface. When the mandrel moves upward and returns to its original position, the locking hook returns to the space between the first protrusion and the second protrusion through the arc-shaped ramp surface on the second protrusion.

[0008] Preferably, the bottom end of the mandrel is provided with an inner tube, and a spring is provided around the inner tube. A step is provided below the drill string, the bottom of the spring rests on the step, and the top is fixed at the connection between the inner tube and the mandrel. The mandrel drives the inner tube to move up and down, and the spring deforms accordingly when the mandrel moves up and down.

[0009] Preferably, the mandrel is raised and lowered by an elastic non-metallic ball, plugging mud, and two steel balls. The inner hole of the mandrel is provided with an annular boss. The diameter of the elastic non-metallic ball is larger than the inner diameter of the boss, and the diameter of the steel ball is larger than the inner diameter of the second circulation hole. The plugging method of the elastic non-metallic ball, plugging mud, and two steel balls in the well includes the following steps: (1) First, put the elastic non-metallic ball into the mandrel; (2) After the elastic non-metallic ball falls into the boss, it plugs the inner hole of the mandrel, and then the plugging mud is injected into the mandrel; (3) As the plugging mud is continuously injected, the mandrel moves down and the spring is compressed and contracted; (4) After the mandrel moves down, the first circulation hole and the second circulation hole correspond to each other, so that the mandrel and the inside and outside of the well are connected; (5) Continue to inject the plugging mud into the mandrel, so that the plugging mud flows through the first circulation hole and the second circulation hole to the leakage crack in the well sidewall; (6) After the plugging is completed, ordinary mud is injected into the mandrel to replace the plugging mud in the well. (7) Insert two steel balls into the drill string. The steel balls will reach the position of the plugging circulation hole with the mud and block the circulation holes on both sides. (8) Under the action of mud pressure, the elastic non-metallic ball is squeezed and deformed and moves downward, falling into the ball catcher through the inner hole of the mandrel. (9) After the mandrel is connected from top to bottom, it moves upward to reset and ensures that the first circulation hole and the second circulation hole are misaligned to complete the plugging.

[0010] Preferably, a slide is provided between the mandrel and the drill string, the slide is provided along the length of the drill string, and the mandrel moves up and down inside the drill string through the slide.

[0011] Preferably, the ball catcher has a cavity inside, which is connected to the spindle. The bottom and surrounding area of ​​the ball catcher are provided with multiple through holes. The bottom surface of the ball catcher is provided with multiple ball-fixing pins, which are vertically arranged.

[0012] Preferably, the bottom of the ball catcher is also provided with an annular notch, the cross-section of the annular notch is semi-circular, and the bottom end of the annular notch is tangent to the bottom surface of the ball catcher.

[0013] Compared with existing technologies, this oil well plugging structure has the following advantages in use: 1. The first protrusion, the second protrusion, the elastic fins, and the locking hook cooperate with each other to ensure the stability of the mandrel when not plugging, preventing the mandrel from moving up and down and achieving a good locking effect; 2. The mandrel is sealed at the protrusion by the elastic non-metallic ball. As the mud is continuously injected and the internal pressure increases, the entire mandrel will disengage from the locking hook and move downward until the two circulation holes are connected, allowing the plugging mud to flow to the leak and complete the plugging; 3. The two steel balls, along with the mud, seal the circulation holes on both sides, again preventing the mandrel from being connected up and down. The pressure forces the elastic non-metallic ball to deform, realizing the mandrel's penetration, while the entire structure is reset by the spring; 4. When plugging, ordinary mud is injected into the mandrel to replace the plugging mud in the drill string, preventing the plugging mud from entering the well and affecting drilling; 5. The ball catcher can effectively capture the elastic non-metallic ball and the two steel balls, preventing them from shaking and colliding during rotary drilling, reducing drilling errors and preventing wellbore deviation. Attached Figure Description

[0014] Figure 1 This is a schematic diagram of the internal structure of an oil well plugging structure according to the present invention. Figure 1 .

[0015] Figure 2 This is a schematic diagram of the internal structure of an oil well plugging structure according to the present invention. Figure 2 .

[0016] Figure 3 This is a schematic diagram of the structure of the elastic non-metallic ball sealing mandrel in the oil well plugging structure of the present invention.

[0017] Figure 4 This is a schematic diagram of the steel ball and elastic non-metallic ball sealing mandrel in an oil well plugging structure according to the present invention.

[0018] Figure 5 For the present invention Figure 1 A magnified structural diagram of the middle section.

[0019] Figure 6 This is a schematic diagram of the connection structure between the fixing ring and the mandrel in an oil well plugging structure according to the present invention.

[0020] Figure 7 This is a schematic diagram of the fixed ring in an oil well plugging structure according to the present invention.

[0021] Figure 8 This is a schematic diagram of the ball catcher in an oil well plugging structure according to the present invention.

[0022] In the diagram: 1. Drilling; 2. Drill string; 21. First circulation hole; 22. Step; 3. Mandrel; 31. First protrusion; 32. Second protrusion; 33. Boss; 34. Second circulation hole; 35. Slide; 36. Inner tube; 37. Spring; 4. Fixing ring; 41. Elastic fin; 42. Locking hook; 5. Leakage gap; 6. Elastic non-metallic ball; 7. Leak-sealing mud; 8. Steel ball; 9. Ball catcher; 91. Cavity; 92. Through hole; 93. Ball-fixing needle; 94. Annular notch. Detailed Implementation

[0023] The present invention will now be described in further detail with reference to the accompanying drawings. The drawings are simplified schematic diagrams, illustrating only the basic structure of the invention in a schematic manner, and therefore only show the components relevant to the invention.

[0024] Please refer to Figure 1-8 A leak sealing structure for oil drilling includes a well 1 and a drill string 2 within the well 1. A mandrel 3 is provided between the mandrel 3 and the drill string 2, and the mandrel 35 is provided along the length of the drill string 2. The mandrel 3 moves up and down within the drill string 2 via the mandrel 35. The drill string 2 contains a mandrel 3 that can move up and down. The drill string 2 has a first circulation hole 21 symmetrically arranged around its circumference, and the mandrel 3 has a second circulation hole 34 around its circumference. Under normal conditions, the first circulation hole 21 and the second circulation hole 34 are misaligned. When the mandrel 3 moves downward so that the first circulation hole 21 aligns with the second circulation hole 34, the plugging mud 7 flows into the well 1 and towards the leak 5, thereby achieving well plugging. The bottom end of the mandrel 3 is equipped with a ball catcher 9, which is connected to the well 1. When plugging is used, the mandrel moves downward and then plugging mud is injected into the mandrel. The plugging mud flows into the leak 5 through the first circulation hole 21 and the second circulation hole 34. After plugging is completed, the mandrel rises back to its original position and continues drilling.

[0025] In this invention, the inner wall of the drill string 2 is provided with a fixing ring 4, and a plurality of elastic fins 41 are evenly arranged below the fixing ring 4. The ends of the elastic fins 41 are provided with locking hooks 42, and the bottom outer side of the locking hooks 42 is provided with an arc-shaped ramp surface. The inner wall of the mandrel 3 is provided with a first protrusion 31 and a second protrusion 32. When the mandrel 3 is locked, the locking hook is located between the first protrusion 31 and the second protrusion 32. When the mandrel 3 moves downward, the second protrusion 32 abuts against the locking hook 42, causing the plurality of elastic fins 41 to move towards the axis respectively. The direction converges, and the outer side of the second protrusion 322 is also provided with an arc-shaped ramp surface. When the spindle 3 moves upward and returns to its original position, the locking hook 42 returns to the space between the first protrusion 31 and the second protrusion 32 through the arc-shaped ramp surface on the second protrusion 32. Under normal conditions, the spindle is connected vertically, and the internal locking hook 42 is engaged between the first protrusion 31 and the second protrusion 32, which can keep the spindle stable. Whether the spindle moves downward or upward, it needs to abut the locking hook 42 through the second protrusion 32 to make the elastic fin 41 move towards the axis. The mandrel 3 has an inner tube 36 at its bottom end, and a spring 37 is provided around the inner tube 36. A step 22 is provided below the drill string 2. The bottom of the spring 37 rests on the step 22, and the top is fixed at the connection between the inner tube 36 and the mandrel 3. The mandrel 3 drives the inner tube 36 to move up and down. When the mandrel 3 moves up and down, the spring 37 deforms accordingly. When it moves upward to reset, the upward elastic force of the spring 37 also moves the elastic fins to lock the mandrel on the locking hook.

[0026] Furthermore, the mandrel 3 achieves vertical movement via an elastic non-metallic ball 6, plugging mud 7, and two steel balls 8. The elastic non-metallic ball 6 is a deformable sphere such as an elastic rubber ball or an elastic coil. The inner hole of the mandrel 3 has an annular boss 33. The diameter of the elastic non-metallic ball 6 is larger than the inner diameter of the boss 33, and the diameter of the steel balls 8 is larger than the inner diameter of the second circulation hole 34. The plugging method using the elastic non-metallic ball 6, plugging mud 7, and two steel balls 8 within the drilling rig 1 includes the following steps: (1) First, put the elastic non-metallic ball 6 into the mandrel 3. The elastic non-metallic ball 6 falls on the boss 33 by its own weight. (2) After the elastic non-metallic ball 6 falls on the boss 33, it blocks the inner hole of the mandrel 3. Then, inject the plugging mud 7 into the mandrel 3. (3) Because the inner hole of the mandrel is blocked by the elastic non-metallic ball 6, the mandrel is not connected from top to bottom. As the plugging mud 7 is continuously injected, the mandrel 3 moves down under the action of the mud, and the spring 37 is compressed and contracted. (4) After the mandrel 3 moves down, the first circulation hole 21 and the second circulation hole 34 correspond to each other, so that the mandrel 3 and the well 1 are connected inside and outside. (5) Continue to inject the plugging mud 7 into the mandrel 3, so that the plugging mud flows through the first circulation hole 21 and the second circulation hole 34 to the leak 5 in the well sidewall to complete the sealing. (6) After the plugging is completed, inject ordinary mud into the mandrel 3 to replace the plugging mud in the drill string and prevent the plugging mud from entering the well. (7) Two steel balls 8 are put into the drill string 2. The steel balls 8 will reach the position of the plugging circulation hole (the first circulation hole 21 corresponds to the second circulation hole 34) with the mud and block the circulation holes on both sides. At this time, the inner hole of the mandrel is no longer connected vertically. The middle is blocked by the elastic non-metallic ball and the two steel balls. (8) Under the action of mud pressure, the elastic non-metallic ball 6 is squeezed and deformed and moves downward through the boss 33. After passing through the boss, the inner hole of the mandrel is connected vertically. At the same time, the steel ball also falls down. The elastic non-metallic ball and the two steel balls finally fall into the ball catcher 9 through the inner hole of the mandrel. (9) After the mandrel 3 is connected vertically, it moves upward to reset and ensures that the first circulation hole 21 and the second circulation hole 34 are misaligned to complete the plugging.

[0027] This plugging structure achieves sealing or connection twice during use through the pressure of mud / plugging mud on the mandrel. The first step involves the elastic non-metallic ball 6 sealing the mandrel at the boss 33. As mud is continuously injected and the internal pressure increases, the mandrel will disengage from the locking hook 42 and move downwards until the two circulation holes (first circulation hole 21 and second circulation hole) connect. After connection, the mud inside the mandrel will flow out of the circulation holes into the wellbore, and the plugging mud will flow towards the leak in the same way to complete the plugging. The second step involves two steel balls 8, which, along with the mud, will block the circulation holes on both sides. At this point, the spindle 3 is blocked again. The spindle 3 moves down and the spring 37 continues to be compressed. When it moves down to the maximum distance, the elastic non-metallic ball 6 is squeezed and deformed, passes through the boss 33 and falls down. After the elastic non-metallic ball 6 passes through the boss 33, the spindle 3 is connected from top to bottom. The two steel balls 8 will not continue to block the circulation hole, but will fall down with the mud until the elastic non-metallic ball and the steel ball fall into the ball catcher 9 below to complete the leak sealing. The spindle will move upward with the tension of the spring 37, and the oscillating hook and elastic fin will be locked between the first boss 31 and the second boss 32.

[0028] In addition, the ball catcher 9 has a cavity 91 connected to the mandrel 3. Multiple through holes 92 are evenly distributed around the bottom of the ball catcher 9. As the elastic non-metallic balls and steel balls fall into the ball catcher 9, the mud will be thrown out through the through holes 92, ensuring that only the elastic non-metallic balls and steel balls are captured. Multiple ball-fixing pins 93 are vertically positioned on the bottom surface of the ball catcher 9. When the elastic non-metallic ball falls into the ball catcher 9, it strikes the ball-fixing pin 93, preventing it from moving within the catcher. During drilling... This design enhances overall stability and prevents issues such as instability and eccentric drilling. Furthermore, the bottom of the ball catcher 9 is equipped with an annular notch 94. The annular notch 94 has a semi-circular cross-section, and its bottom end is tangent to the bottom surface of the ball catcher 9. When the ball-fixing needle penetrates the elastic non-metallic ball, the two steel balls will fall downwards from the inner wall of the ball catcher 9. During drilling, the steel balls are flung into the annular notch 94 by centrifugal force, further preventing the steel balls from shaking and colliding within the ball catcher, reducing drilling errors, preventing drilling line deviation, and further improving drilling stability.

[0029] Obviously, the above embodiments are merely illustrative examples for clear explanation and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. However, obvious variations or modifications derived therefrom are still within the scope of protection of this invention.

Claims

1. A plugging structure for oil well drilling, comprising a well and a drill string within the well, characterized in that, The drill string is equipped with a mandrel that can move up and down. The drill string has a first circulation hole symmetrically arranged around its circumference, and the mandrel has a second circulation hole around its circumference. Under normal conditions, the first circulation hole and the second circulation hole are misaligned. When the mandrel moves down so that the first circulation hole aligns with the second circulation hole, the plugging mud flows out into the well and towards the leak. The bottom end of the mandrel is equipped with a ball catcher, which is connected to the well. The drill string has a fixing ring on its inner wall, and multiple elastic fins are evenly arranged below the fixing ring. The ends of the elastic fins are provided with locking hooks, and the bottom outer side of the locking hooks is provided with an arc-shaped ramp surface. The inner wall of the mandrel is provided with a first protrusion and a second protrusion. When the mandrel is locked, the locking hook is located between the first protrusion and the second protrusion. When the mandrel moves downward, the second protrusion abuts against the locking hook and causes the multiple elastic fins to converge towards the axis. The outer side of the second protrusion is also provided with an arc-shaped ramp surface. When the mandrel moves upward and returns to its original position, the locking hook returns to the space between the first protrusion and the second protrusion through the arc-shaped ramp surface on the second protrusion. The mandrel has an inner tube at its bottom end, and a spring is provided around the inner tube. A step is provided below the drill string. The bottom of the spring rests on the step, and the top is fixed at the connection between the inner tube and the mandrel. The mandrel drives the inner tube to move up and down, and the spring deforms accordingly when the mandrel moves up and down. The mandrel is raised and lowered by an elastic non-metallic ball, plugging mud, and two steel balls. The inner hole of the mandrel is provided with an annular boss. The diameter of the elastic non-metallic ball is larger than the inner diameter of the boss, and the diameter of the steel ball is larger than the inner diameter of the second circulation hole. The plugging method of the elastic non-metallic ball, plugging mud, and two steel balls in the well includes the following steps: (1) First, put the elastic non-metallic ball into the mandrel; (2) After the elastic non-metallic ball falls into the boss, it plugs the inner hole of the mandrel, and then the plugging mud is injected into the mandrel; (3) As the plugging mud is continuously injected, the mandrel moves down and the spring is compressed and contracted; (4) After the mandrel moves down, the first circulation hole and the second circulation hole correspond to each other, so that the mandrel and the inside and outside of the well are connected; (5) Continue to inject the plugging mud into the mandrel, so that the plugging mud flows through the first circulation hole and the second circulation hole into the leakage crack of the well sidewall; (6) After the plugging is completed, ordinary mud is injected into the mandrel to replace the plugging mud in the drill string; (7) Insert two steel balls into the drill string. The steel balls will reach the positions corresponding to the first and second circulation holes with the mud. (8) Under the action of mud pressure, the elastic non-metallic balls are squeezed and deformed and move downwards, falling into the ball catcher through the inner hole of the mandrel. (9) After the mandrel is connected from top to bottom, it moves upwards to reset and ensure that the first and second circulation holes are misaligned to complete the plugging. The ball catcher has a cavity inside, which is connected to the spindle. The bottom and surrounding area of ​​the ball catcher have multiple through holes evenly distributed. The bottom surface of the ball catcher has multiple ball-fixing pins, which are vertically arranged.

2. The oil well plugging structure according to claim 1, characterized in that, A slide is also provided between the mandrel and the drill string. The slide is set along the length of the drill string, and the mandrel moves up and down inside the drill string through the slide.

3. The oil well plugging structure according to claim 2, characterized in that, The bottom of the ball catcher is also provided with an annular notch, the cross-section of which is semi-circular, and the bottom end of which is tangent to the bottom surface of the ball catcher.

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