Long-acting locked-rotor fracturing device and fracturing method

Abstract

The invention discloses a long-acting locked-rotor fracturing device, and relates to the technical field of efficient exploitation of oil fields. Comprising a fracturing pipeline and a ball throwing device, a ball outlet in the ball throwing device is connected to the fracturing pipeline, and the ball throwing device comprises a ball storage pipe used for storing long-acting temporary plugging balls in batches; the spherical sleeve is communicated with one side of the ball storage pipe; one end of the guide pipe is communicated with the other side of the ball storage pipe, and the other end of the guide pipe is communicated with a fracturing pipeline; the spherical conveying body is arranged in the spherical sleeve, two sealing rings are arranged on the inner wall of the spherical sleeve, the two sealing rings are used for a gap between the spherical conveying body sleeve and the spherical conveying body, and the spherical conveying body is driven by the motor to rotate. In the ball throwing device, a disc-shaped rotating component in the prior art is replaced by the spherical rotating component (namely the spherical conveying body), and after the shape of the rotating component is changed, the ball inlet and the ball outlet of the ball throwing device can be sealed through the sealing rings, so that the sealing problem can be solved.

Description

Technical Field

[0001] The present invention relates to the field of efficient oilfield exploitation, and particularly to a long-acting plugging and fracturing device. Background Art

[0002] Fracturing is a commonly used construction technique in the process of oil and gas drilling and exploitation of deep-sea and land horizontal wells. Its principle is to apply pressure to the downhole formation through high-pressure fracturing fluid, causing the formation to crack at weak points, thereby creating new fractures in the formation, so that the oil and gas contained in the formation can be released. The fracturing device is an important branch of oil (gas) field oil production and gas production equipment.

[0003] Plugging and fracturing, also known as temporary plugging and diversion fracturing, is a situation where, after fractures have been created in the formation, long-acting temporary plugging balls are introduced into the downhole fracturing fluid to block the original fractures, so as to reduce the pressure loss caused by the original fractures, thereby making the pressure act more concentratedly on other positions of the formation and creating new fractures.

[0004] In a patent document of an invention patent applied by a professional scientific research team of Southwest Petroleum University and with the authorization announcement number CN114562246B, a continuous ball throwing device for intelligent monitoring fracturing temporary plugging is disclosed. By controlling the rotation of the rotating ball throwing disc in an automatic control manner, continuous, automatic, and unmanned ball throwing is realized, which has a certain degree of advancement. However, further research found that although the technical solution provided by this patent provides a new idea for the design of fracturing devices and temporary plugging ball throwing devices, this technical solution has obvious defects: In the above patent technology, a part of the rotating ball throwing disc 17 is located in the main body 1 with extremely high pressure, and another part is located in the space below the normal-pressure ball storage tube. That is to say, the pressure difference between the left and right parts of the rotating ball throwing disc 17 is as high as dozens of megapascals.

[0005] In this case, the disc shape and rotatable structure of the rotating ball throwing disc determine that it is very difficult to ensure the sealing of its various surfaces (including the upper and lower end faces and the outer circumferential surface). In the case of a pressure difference as high as dozens of megapascals, a large amount of fracturing fluid will leak. In fact, there is no sealing structure in the prior art that can ensure its sealing, and the above patent document does not give a corresponding sealing structure either. Summary of the Invention

[0006] The present invention provides a long-acting plugging and fracturing device, aiming to optimize the existing ball throwing and temporary plugging fracturing technology introduced in the background art and solve the sealing problem existing in the above patent technology.

[0007] The technical problem solved by the present invention is realized by adopting the following technical solutions: The present invention provides a long-acting plugging and fracturing device, including a fracturing pipeline and a ball throwing device. The ball outlet on the ball throwing device is connected to the fracturing pipeline. The ball throwing device includes: A ball storage tube for storing a large number of long-acting temporary plugging balls in batches; A spherical sleeve, which is connected to one side of the ball storage tube; A guiding tube, one end of which is connected to the other side of the ball storage tube, and the other end of which is connected to a fracturing pipeline; A spherical conveyor is arranged inside the spherical sleeve. There are two sealing rings arranged on the inner wall of the spherical sleeve, and both sealing rings are used for the gap between the spherical conveyor and the spherical sleeve. Among them, one sealing ring is arranged at the connection between the ball storage tube and the spherical sleeve, and the other sealing ring is arranged at the connection between the guiding tube and the spherical sleeve; A motor, the output shaft of which passes through the spherical sleeve and is connected to the spherical conveyor, and the spherical conveyor rotates under the drive of the motor.

[0008] A remote controller, which can control the starting and stopping time of the motor and record the number of turns and angles of the motor rotation; The surface of the spherical conveyor is processed with ball grooves for accommodating long-acting temporary plugging balls. During the rotation of the spherical conveyor, when the long-acting temporary plugging balls located in the ball storage tube fall into the ball grooves, they reach the entrance of the guiding tube along with the rotation of the spherical conveyor and then enter the guiding tube.

[0009] As a preferred solution, on the spherical conveyor, the number of ball grooves is one.

[0010] As a preferred solution, on the spherical conveyor, the number of ball grooves is three, and the three ball grooves are evenly distributed along the maximum circumference of the outer surface of the spherical conveyor.

[0011] As a preferred solution, a pop-up mechanism is arranged at the bottom of the ball groove. The pop-up mechanism includes a ball seat and a compression spring, and the compression spring elastically supports the ball seat in the ball groove; A pressure rod is slidably installed at the end of the ball storage tube, and the pressure rod can overcome the elastic force of the compression spring to press the long-acting temporary plugging ball into the ball groove.

[0012] As a preferred solution, each ball groove can accommodate two long-acting temporary plugging balls, and the two long-acting temporary plugging balls are arranged radially along the spherical conveyor.

[0013] As a preferred solution, a tension spring is connected between the pressure rod and the ball storage tube, and the tension spring can help the pressure rod overcome the elastic force of the compression spring.

[0014] As a preferred solution, a drain pipe is connected to the side of the ball storage tube, and the drain pipe can immediately drain the fracturing fluid carried out by the ball groove, which is beneficial to collection.

[0015] The present invention also provides a fracturing method for a long-acting stuck-rotor fracturing device according to any one of the above claims 1-6, characterized by comprising the following steps: Step 1: Segment the well depth according to the reservoir geological conditions, conduct the first fracturing on a certain section, press open the first fracture under pressure, and determine that the first fracture is fractured in place through instrument indications; Step 2: Start the motor through manual remote control means or automatic control means to rotate the spherical conveyor, and then gradually put the long-acting temporary plugging balls in the ball storage pipe into the downhole fracturing fluid. The long-acting temporary plugging balls enter the downhole fracture with the flow of the fracturing fluid and block all or part of the first fracture; Step 3: After plugging, the loss of the fracturing fluid is reduced or stopped. Continuously build pressure to make the fracturing position naturally turn to other places, and then press open the second fracture. Determine that the second fracture is fractured in place through instrument indications. After confirming that the fracturing is in place, stop the motor through manual remote control or automatic control; Step 4: Continue to fracture the third fracture or more fractures according to the above method; Step 5: Press open the last fracture and inject the displacement fluid to complete the fracturing construction.

[0016] The beneficial effects of the present invention are: 1. In the ball injection device, a spherical rotating part (i.e., the spherical conveyor) is used to replace the disc-shaped rotating part in the prior art. After changing the shape of the rotating part, no matter what angle the spherical conveyor rotates to, at least one sealing ring can completely seal the gap between the spherical conveyor and the spherical sleeve, so that the pressure of the fracturing system will not leak from the ball injection device, and the sealing problem can be solved. Therefore, the change in the shape of the rotating part in the ball injection device is the most important innovation of the present invention.

[0017] 2. The present invention is provided with a sliding pressure rod on the ball storage pipe. The downward pressure of the pressure rod on the long-acting temporary plugging ball has the following advantages: First, the pressure rod can overcome the elastic force of the compression spring, so as to press the long-acting temporary plugging ball into the ball groove.

[0018] Second, after the spherical conveyor rotates, the ball groove may carry the fracturing fluid to the entrance of the long-acting temporary plugging ball, making it difficult for the long-acting temporary plugging ball waiting to be injected to fall into the ball groove (the density of the temporary plugging ball is sometimes less than that of the fracturing fluid, so the long-acting temporary plugging ball is not easy to fall). After the pressure rod applies pressure to the long-acting temporary plugging ball, the fracturing fluid in the ball groove can be quickly discharged, and the long-acting temporary plugging ball can also quickly enter the ball groove.

[0019] Third, the setting of the pressure rod enables the ball storage pipe to be inclined, placed horizontally, or even inverted, greatly improving the flexibility of the space layout at the operation site.

[0020] 3. By setting a pop-up mechanism on the spherical conveyor, the falling action of the long-acting temporary plugging ball no longer relies on its own gravity, resulting in two benefits: On the one hand, for long-acting temporary plugging balls with a relatively small density, the buoyancy from the fracturing fluid will prevent the long-acting temporary plugging balls from sliding into the pressure pipeline actively. However, by applying an elastic force to the long-acting temporary plugging balls through the pop-up mechanism, the buoyancy from the fracturing fluid can be overcome, and the long-acting temporary plugging balls can be accelerated to slide into the fracturing pipeline. As a result, the ball injection device can be applicable to both long-acting temporary plugging balls with a density greater than that of the fracturing fluid and long-acting temporary plugging balls with a density smaller than that of the fracturing fluid.

[0021] On the other hand, the long-acting temporary plugging balls no longer rely on gravity to fall, so that the ball injection device can be arbitrarily set at any position of the fracturing pipeline (not necessarily near the wellhead), and can also be at any angle with the fracturing pipeline, effectively improving the flexibility of the on-site operation space layout and facilitating other operations. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 is the overall structural schematic diagram of the present invention.

[0023] Figure 2 is Figure 1 the structural schematic diagram of the ball injection device in

[0024] Figure 3 the structural schematic diagram at the spherical conveyor.

[0025] Figure 4 is Figure 3 the left view cross-sectional view at A-A in

[0026] Figure 5 、 Figure 6 is Figure 4 the position state diagram when the spherical conveyor rotates to different positions in

[0027] Figure 7 、 Figure 8 is the structural schematic diagram when a pop-up device is arranged in the ball groove when the number of ball grooves is one or three.

[0028] In the figure: 1, fracturing pipeline; 2, guide pipe; 3, spherical sleeve; 4, spherical conveyor; 5, long-acting temporary plugging ball; 6, pressure rod; 7, tension spring; 8, sealing ring; 9, ball groove; 10, motor; 12, ball seat; 13, drain pipe. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0029] The following further describes the present invention with reference to the drawings.

[0030] As shown in Figure 1As shown in the figure, this embodiment includes a fracturing pipeline 1 and a ball injection device. A rotating component is arranged inside the ball injection device, and the long-term temporary plugging ball 5 is delivered through the rotation of the rotating component. The ball outlet on the ball injection device is connected to the fracturing pipeline 1 so as to deliver the long-term temporary plugging ball 5 into the hydraulic system where the fracturing fluid is located. The above is the conventional structure in the prior art and will not be elaborated here.

[0031] As Figure 1 , 2 shown in the figure, in this embodiment, the ball injection device includes a ball storage pipe, a spherical sleeve 3, a guide pipe 2, a spherical conveyor 4, a motor 10 and a remote controller. The ball storage pipe is used for storing a batch of long-term temporary plugging balls 5. It is connected to the external atmospheric pressure and isolated from the hydraulic system where the fracturing fluid is located, so it is in an atmospheric pressure state. Therefore, a series of problems caused by high pressure do not need to be considered when replenishing the temporary plugging balls, and the operation is very convenient and safe. The spherical sleeve 3 is connected to one side of the ball storage pipe, so that the long-term temporary plugging ball 5 can enter the spherical sleeve 3. One end of the guide pipe 2 is connected to the other side of the ball storage pipe, so that the long-term temporary plugging ball 5 can be removed from the spherical sleeve 3. The other end of the guide pipe 2 is connected to the fracturing pipeline 1, so that the long-term temporary plugging ball 5 can be delivered into the fracturing pipeline 1.

[0032] As Figure 1 , 2 shown in the figure, in this embodiment, the spherical conveyor 4 is arranged inside the spherical sleeve 3. Two sealing rings 8 are arranged on the inner wall of the spherical sleeve 3. Both of the two sealing rings 8 are used for the gap between the spherical conveyor 4 and the spherical sleeve 3. Among them, one sealing ring 8 is arranged at the connection between the ball storage pipe and the spherical sleeve 3, and the other sealing ring 8 is arranged at the connection between the wire pipe and the spherical sleeve 3. During use, the two sealing rings 8 alternately participate in sealing, so that no matter what angle the spherical conveyor 4 rotates to, at least one sealing ring 8 can completely seal the gap between the spherical conveyor 4 and the spherical sleeve 3, so that the pressure of the fracturing system will not leak from the ball injection device.

[0033] As Figure 3 shown in the figure, in this embodiment, the output shaft of the motor 10 passes through the spherical sleeve 3 and is connected to the spherical conveyor 4. The spherical conveyor 4 rotates under the drive of the motor 10. The remote controller can control the start and stop timing of the motor 10 and record the number of turns and angles of the motor 10. Among them, how the remote controller realizes the control of the motor 10 belongs to the conventional prior art and will not be elaborated here.

[0034] As Figure 1 , 2As shown in FIGS. 3 or 4, in this embodiment, a ball groove 9 for accommodating the long-acting temporary plugging ball 5 is machined on the surface of the spherical conveyor 4. During the rotation of the spherical conveyor 4, after the long-acting temporary plugging ball 5 located in the ball storage tube falls into the ball groove 9, it reaches the entrance of the guiding tube 2 along with the rotation of the spherical conveyor 4 and then enters the guiding tube 2.

[0035] In this embodiment, in the ball throwing device, a spherical rotating member (i.e., the spherical conveyor 4) is used instead of the disc-shaped rotating member in the prior art. After changing the shape of the rotating member, no matter what angle the spherical conveyor 4 rotates to, at least one sealing ring 8 can completely seal the gap between the spherical conveyor 4 and the spherical sleeve 3, so that the pressure of the fracturing system will not leak from the ball throwing device, thus solving the sealing problem. Therefore, the change in the shape of the rotating member in the ball throwing device is the most important innovation of the present invention.

[0036] In this embodiment, on the spherical conveyor 4, the number of the ball grooves 9 can be one. The advantage of one ball groove 9 is stable sealing, and the disadvantage is low ball throwing efficiency. In order to improve the ball throwing efficiency, two long-acting temporary plugging balls 5 can be accommodated in each ball groove 9, and the two long-acting temporary plugging balls 5 are arranged along the radial direction of the spherical conveyor 4, so that two long-acting temporary plugging balls 5 can be put in at one time, doubling the ball throwing efficiency.

[0037] As Figure 3 、 4 、5, and 6 show, in some embodiments, on the spherical conveyor 4, the number of the ball grooves 9 can be three, and the three ball grooves 9 are evenly distributed along the largest circumference of the outer surface of the spherical conveyor 4. When the number of the ball grooves 9 is three, it is necessary to adjust the distance between two adjacent ball grooves 9 by adjusting the diameter size of the spherical conveyor 4, so that the two sealing rings 8 can participate in sealing alternately, ensuring the continuity of the sealing state.

[0038] Figure 4 、 5 、6 show three typical position states after the rotation of the spherical conveyor 4. The three figures successively show three consecutive position state changes occurring once within one clockwise rotation of the spherical conveyor 4. Among them, Figure 4 and 5 the upper sealing ring 8 participates in sealing, Figure 6 in

[0039] the lower sealing ring 8 begins to participate in sealing, and the upper sealing ring 8 begins to fail. Figure 7 As shown in FIGS. 7 or 8, in some embodiments, a pop-up mechanism is provided at the bottom of the ball groove 9. The pop-up mechanism includes a ball seat 12 and a compression spring, and the compression spring elastically supports the ball seat 12 in the ball groove 9. By providing a pop-up mechanism on the spherical conveyor 4, the falling action of the long-acting temporary plugging ball 5 no longer depends on its own gravity, thus bringing two benefits: On the one hand, for the long-acting temporary plugging ball 5 with a smaller density, the buoyancy from the fracturing fluid will prevent the long-acting temporary plugging ball 5 from actively sliding into the pressure pipeline. By applying an elastic force to the long-acting temporary plugging ball 5 through the ejection mechanism, the buoyancy from the fracturing fluid can be overcome, and the long-acting temporary plugging ball 5 can be accelerated to slide into the fracturing pipeline 1. Thus, the ball injection device can be applicable to both the long-acting temporary plugging ball 5 with a density greater than that of the fracturing fluid and the long-acting temporary plugging ball 5 with a density smaller than that of the fracturing fluid.

[0040] On the other hand, it enables the long-acting temporary plugging ball 5 not to rely on gravity to fall, and further enables the ball injection device to be arbitrarily set at any position of the fracturing pipeline 1 (not necessarily near the wellhead), and can also be at any angle with the fracturing pipeline 1, thus effectively improving the flexibility of the on-site operation space layout and facilitating other operations.

[0041] A pressure rod 6 is slidably installed at the end of the ball storage tube. The pressure rod 6 can overcome the elastic force of the compression spring, thereby pressing the long-acting temporary plugging ball 5 into the ball groove 9. The downward pressing action of the pressure rod 6 on the long-acting temporary plugging ball 5 has the following several advantages: First, the pressure rod 6 can overcome the elastic force of the compression spring, thereby pressing the long-acting temporary plugging ball 5 into the ball groove 9.

[0042] Second, after the spherical conveyor 4 rotates, the ball groove 9 may carry the fracturing fluid to the entrance of the long-acting temporary plugging ball 5, making it difficult for the long-acting temporary plugging ball 5 waiting to be injected to fall into the ball groove 9 (sometimes the density of the temporary plugging ball is less than that of the fracturing fluid, so the long-acting temporary plugging ball 5 is not easy to fall). After the pressure rod 6 applies pressure to the long-acting temporary plugging ball 5, the fracturing fluid in the ball groove 9 can be quickly discharged, and the long-acting temporary plugging ball 5 can also quickly enter the ball groove 9.

[0043] Third, the setting of the pressure rod 6 enables the ball storage tube to be inclined, placed horizontally, or even inverted, greatly improving the flexibility of the on-site operation space layout.

[0044] As shown in Figure 1 or 2, in some embodiments, a tension spring 7 is connected between the pressure rod 6 and the ball storage tube. Whether the ball storage tube is placed horizontally, vertically, or even inverted, the tension spring 7 can help the pressure rod 6 overcome the elastic force of the compression spring.

[0045] During specific implementation, a drain pipe 13 can be connected to the side of the ball storage tube. The drain pipe 13 can immediately discharge the fracturing fluid carried out by the ball groove 9, which is beneficial for collection.

[0046] The present invention also provides a fracturing method for a long-acting plugging and fracturing device based on any one of the above claims 1-6, characterized in that it includes the following steps: Step 1: Segment the well depth according to the reservoir geological conditions, conduct the first fracturing on a certain section, press open the first fracture under pressure, and determine that the fracturing of the first fracture is in place through instrument indications. Step 2: Start the motor 10 by means of manual remote control or automatic control to rotate the spherical conveyor 4, and then gradually put the long-acting temporary plugging balls 5 in the ball storage pipe into the downhole fracturing fluid. The long-acting temporary plugging balls 5 enter the downhole fracture with the flow of the fracturing fluid and block all or part of the first fracture. Step 3: After plugging, the loss of the fracturing fluid decreases or stops. Keep the pressure on to make the fracturing position naturally turn to other places, and then press open the second fracture. Determine that the fracturing of the second fracture is in place through instrument indications. After confirming that the fracturing is in place, stop the motor 10 by means of manual remote control or automatic control. Step 4: Continue to fracture the third fracture or more fractures according to the above method. Step 5: Press open the last fracture and inject the displacement fluid to complete the fracturing construction.

Claims

1. A long-term blocked rotor fracturing device, comprising a fracturing pipeline (1) and a ball throwing device, wherein a ball outlet on the ball throwing device is connected to the fracturing pipeline (1), characterized in that: The pitching device includes: A ball storage tube, used for storing long-acting temporary plugging balls in batches (5); A spherical sleeve (3), the spherical sleeve (3) being communicated with one side of the ball storage tube; A guide tube (2), one end of the guide tube (2) being connected to the other side of the ball storage tube, and the other end of the guide tube (2) being connected to the fracturing pipeline (1); A spherical conveying body (4), the spherical conveying body (4) being arranged inside the spherical sleeve (3), and two sealing rings (8) being arranged on the inner wall of the spherical sleeve (3), and the two sealing rings (8) are both used for the gap between the spherical sleeve and the spherical conveying body (4), wherein one sealing ring (8) is arranged at the connection between the ball storage tube and the spherical sleeve (3), and the other sealing ring (8) is arranged at the connection between the wire tube and the spherical sleeve (3); A motor (10), wherein an output shaft of the motor (10) passes through the spherical sleeve (3) and is connected to the spherical conveying body (4), and the spherical conveying body (4) rotates under the drive of the motor (10); A remote controller, the remote controller being capable of controlling the start and stop timing of the motor (10) and recording the number of revolutions and angles of rotation of the motor (10); The surface of the spherical conveying body (4) is provided with a ball groove (9) for accommodating the long-acting temporary blocking ball (5). During the rotation of the spherical conveying body (4), the long-acting temporary blocking ball (5) in the ball storage tube falls into the ball groove (9), and then reaches the entrance of the guide tube (2) as the spherical conveying body (4) rotates, and then enters the guide tube (2).

2. A long-acting locked-rotor fracturing device according to claim 1, characterized in that: The number of the ball groove (9) on the spherical conveying body (4) is one.

3. A long-acting locked-rotor fracturing device according to claim 1, characterized in that: The number of the ball grooves (9) on the spherical conveying body (4) is three, and the three ball grooves (9) are evenly distributed along the maximum circumference of the outer surface of the spherical conveying body (4).

4. A long-acting locked-rotor fracturing device according to claim 1, characterized in that: A pop-up mechanism is provided at the bottom of the ball groove (9), the pop-up mechanism comprising a ball seat (12) and a compression spring, the compression spring elastically supporting the ball seat (12) in the ball groove (9); A pressure rod (6) is slidably mounted on the end of the ball storage tube, and the pressure rod (6) is capable of overcoming the elastic force of the compression spring, thereby pressing the long-acting temporary blocking ball (5) into the ball groove (9).

5. A long-acting locked-rotor fracturing device according to claim 4, characterized in that: Each of the ball grooves (9) can accommodate two long-acting temporary blocking balls (5), and the two long-acting temporary blocking balls (5) are arranged along the radial direction of the spherical conveying body (4).

6. A long-acting locked-rotor fracturing device according to claim 4, characterized in that: A tension spring (7) is connected between the compression rod (6) and the ball storage tube, and the tension spring (7) can help the compression rod (6) overcome the elastic force of the compression spring.

7. A long-acting locked-rotor fracturing device according to claim 4, characterized in that: A liquid discharge pipe (13) is connected to the side of the ball storage pipe, and the liquid discharge pipe (13) can discharge the fracturing fluid carried out of the ball tank (9) immediately, thereby facilitating collection.

8. A fracturing method based on a long-acting locked-rotor fracturing device according to any one of claims 1 to 7, characterized in that: The following steps are involved: Step 1: The well depth is segmented according to the reservoir geological conditions, and the first fracturing is performed on a certain segment. The first crack is opened under the action of pressure, and the first crack is confirmed to be fully fractured through instrument indication; Step 2: start the motor (10) by manual remote control means or automatic control means to rotate the spherical conveying body (4), and then gradually put the long-term temporary plugging balls (5) in the ball storage tube into the downhole fracturing fluid. The long-term temporary plugging balls (5) enter the downhole cracks along with the flow of the fracturing fluid, and completely or partially plug the first crack; Step 3: After plugging, the leakage of the fracturing fluid is reduced or stopped, and the pressure is continuously held to naturally turn the fracturing position to another place, and then the second fracture is opened, and the second fracture is confirmed to be fractured in place through instrument indication. After confirming that the fracturing is in place, the motor (10) is stopped by manual remote control or automatic control; Step 4, continue fracturing the third crack or more cracks according to the above method; Step 5: Press open the last crack and inject displacement fluid to complete the fracturing construction.

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