Liquid oxygen fracturing pipe upper end cover suitable for underwater rock mass and manufacturing method

Abstract

The invention provides an upper end cover of a liquid oxygen fracturing pipe suitable for underwater rock mass and a manufacturing method, and relates to the technical field of expansion fracturing, the upper end cover comprises an end cover body, counter-force petals are arranged on the upper surface of the end cover body, the counter-force petals are annularly arranged on the upper surface of the end cover body, and the counter-force petals are arranged on the lower surface of the end cover body. The counter-force petals are arranged on the upper end cover, an acute included angle alpha is formed between the counter-force petals and the axial direction of the end cover body, the counter-force petals are made of semi-rigid materials, the end cover body is used for being detachably connected with a fracturing pipe, and the counter-force petals are arranged on the upper end cover, so that the counter-force petals can be clamped to the inner wall of a blast hole, the buoyancy effect of water on the fracturing pipe is counteracted, and the fracturing effect is improved. And therefore, an operator can mount the fracturing pipe at the bottom of the blast hole.

Description

Technical Field

[0001] The invention relates to the technical field of expansion fracturing, and in particular to an upper end cover of a liquid oxygen fracturing pipe suitable for underwater rock mass and a manufacturing method thereof. Background Art

[0002] Liquid oxygen phase change fracturing technology has gradually matured, and the structure of the fracturing tube, which is its most important content, has a relatively mature design process.

[0003] The characteristic of the above-ground liquid oxygen phase change fracturing technology is that it has low requirements for the sealing of the fracturing pipe, and liquid oxygen is mainly stored in a confined space composed of drilling and filling parts. However, when this technology is used underwater, the situation will be completely different. The mass of the fracturing pipe itself is relatively small, and it is portable and flexible when carrying out construction operations on the ground; but during underwater construction, due to the small mass of the fracturing pipe body, its own gravity cannot offset the buoyancy. During the construction of the pipe, the fracturing pipe will float upward along the larger blasthole. This will make it difficult for operators to easily place the pipe body at the bottom of the blasthole, making it impossible to carry out subsequent work efficiently and conveniently.

[0004] Based on the above reasons, the present application provides an upper end cover of a liquid oxygen fracturing tube suitable for underwater rock masses and a method for making the same, aiming to solve the problem that the fracturing tube is not easy to fix during underwater operations. Summary of the invention

[0005] The invention provides an upper end cover of a liquid oxygen fracturing pipe suitable for underwater rock mass and a manufacturing method thereof, and aims to solve the problem that the fracturing pipe is not easy to fix during underwater operation.

[0006] In order to achieve the above object, an embodiment of the present invention provides an upper end cover of a liquid oxygen fracturing pipe suitable for underwater rock mass, comprising:

[0007] An end cover body, wherein reaction petals are arranged on the upper surface of the end cover body, wherein the reaction petals are ring-arranged on the upper surface of the end cover body, wherein the reaction petals form an acute angle α with the axial direction of the end cover body, wherein the reaction petals are made of semi-rigid material, and wherein the end cover body is used for detachable connection with the fracturing tube.

[0008] Preferably, the end cover body comprises a surrounding plate and an end plate, the end plate is arranged above the surrounding plate so that the end cover body forms a semi-enclosed structure, and the surrounding plate is used for detachably connecting with the fracturing tube;

[0009] The end plate is provided with a liquid inlet, an exhaust port and a threading port. The liquid inlet is used for the passage of an infusion tube of the oxygen absorbing medium, the exhaust port is provided with an exhaust pipe or a one-way valve allowing liquid oxygen to flow from the inner cavity of the fracturing tube to the atmosphere, and the threading port is used for the passage of cables of the electronic excitation device.

[0010] Preferably, a ring groove is provided on a side of the end plate facing the enclosure plate, and a sealing ring is provided in the ring groove;

[0011] When the enclosure plate is connected to the fracturing tube, the upper end of the fracturing tube abuts against the sealing ring.

[0012] Preferably, a protective ring is provided on one side of the end plate away from the enclosure plate, and the liquid inlet, the exhaust port and the threading port are located within the protective range formed by the protective ring.

[0013] Preferably, the liquid inlet is a threaded hole, and a two-way quick connector is threaded on the liquid inlet. One end of the two-way quick connector is located inside the fracturing tube and is used to connect with the infusion tube of the oxygen absorption medium, and the other end of the two-way quick connector is located outside the fracturing tube and is used to connect with the extension tube.

[0014] Preferably, the threading opening is a double-concave threading opening, the diameter of the threading opening on the upper and lower surfaces of the end plate is larger than the diameter of the threading opening on the middle surface of the end plate, and the middle surface is located between the upper surface and the lower surface of the end plate.

[0015] The present application also provides a manufacturing method for manufacturing the aforementioned upper end cover, comprising:

[0016] S10. Cast a batch of upper end covers, and bend the reaction petals of one of the upper end covers to any angle, and measure the following parameters of the upper end covers: the radius difference between the outermost radius of the reaction petals and the radius of the test blasthole, the outer diameter of the virtual circle formed by the bottom ends of several reaction petals on the end cover body, the inner diameter of the virtual circle formed by the bottom ends of several reaction petals on the end cover body, the length of the reaction petals, and the number of reaction petals;

[0017] S20. Place the upper end cover in the test blast hole and measure the sliding friction force of the upper end cover in the test blast hole using a tensile tester;

[0018] S30. Based on the cantilever beam model, the proportional relationship between the sliding friction force and the elastic modulus of the reaction force petals and the product of the friction coefficient of the reaction force petals and the hole wall is obtained;

[0019] S40. Confirm the sliding friction of the blast hole where the upper end cover needs to be installed, obtain the radius difference between the outermost radius of the reaction petal and the radius of the installation blast hole, and obtain the angle α at which the reaction petal needs to be deflected.

[0020] Preferably, the cantilever beam model is:

[0021]

[0022] Where f is the sliding friction force between the upper end cover and the blasthole, E is the elastic modulus of the upper end cover, μ is the friction coefficient between the upper end cover and the blasthole, y is the radius difference between the outermost radius of the reaction petal and the radius of the test blasthole, R is the outer diameter of the virtual circle formed by the bottom ends of several reaction petals on the end cover body, r is the inner diameter of the virtual circle formed by the bottom ends of several reaction petals on the end cover body, L is the length of the reaction petal, and n is the number of reaction petals.

[0023] Preferably, in steps S10-S30, the product of the elastic modulus E of the upper end cover and the friction coefficient μ between the upper end cover and the blast hole is calculated, and the deflection angle α of the reaction petals is calculated by combining the sine function and the radius difference y between the outermost radius of the reaction petals and the radius of the test blast hole.

[0024] The above scheme of the present invention has the following beneficial effects:

[0025] In the present application, reaction petals are provided on the upper end cover so that the reaction petals can be snapped onto the inner wall of the blast hole to offset the buoyancy effect of water on the fracturing tube, thereby ensuring that the operator can install the fracturing tube at the bottom of the blast hole.

[0026] Other features and advantages of the present invention will be described in detail in the following detailed description. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 is a schematic diagram of the present invention;

[0028] Figure 2 is a top view of the present invention;

[0029] Figure 3 It is a cross-sectional view in the AA direction;

[0030] Figure 4 It is a schematic diagram of the parameters of this application in the blast hole.

[0031] [Description of Reference Numerals]

[0032] 10-end cover body, 11-enclosure, 12-end plate, 13-seal ring, 14-protection ring, 15-exhaust pipe, 16-check valve, 17-two-way quick connector, 18-nut, 19-threading port,

[0033] 20-Reaction petals. DETAILED DESCRIPTION

[0034] In order to make the technical problems, technical solutions and advantages to be solved by the present invention more clear, a detailed description will be given below with reference to the accompanying drawings and specific embodiments.

[0035] like Figure 1-Figure 4As shown, an embodiment of the present invention provides an upper end cap of a liquid oxygen fracturing pipe suitable for underwater rock mass, comprising an end cap body 10, the upper surface of which is provided with reaction petals 20, which are arranged on the upper surface of the end cap body 10, and the reaction petals 20 and the axial direction of the end cap body 10 form an acute angle α, more precisely, the reaction petals 20 and the positive direction of the axial direction of the end cap body 10 form an acute angle, and the reaction ring plate is made of semi-rigid material, such as PE, which can be deformed when subjected to force. The end cap body 10 is used for detachable connection with the fracturing pipe.

[0036] Furthermore, the end cover body 10 includes a surrounding plate 11 and an end plate 12. The end plate 12 is arranged above the surrounding plate 11 so that the end cover body 10 forms a semi-closed structure. When the surrounding plate 11 is detachably connected to the fracturing tube, the end plate 12 seals the fracturing tube at the upper end of the fracturing tube.

[0037] Since an oxygen absorbing medium needs to be placed in the fracturing tube and liquid oxygen needs to be filled into the oxygen absorbing medium, a liquid inlet is provided on the end plate 12, and the oxygen absorbing medium includes a liquid infusion tube, and the liquid infusion tube is passed through the liquid inlet. An electronic excitation device needs to be installed in the fracturing tube, so a threading port 19 is also provided on the end plate 12, and the cable of the electronic excitation device is passed through the threading port 19. An exhaust port is also provided on the end plate 12, and an exhaust pipe 15 or a one-way valve 16 that allows liquid oxygen to flow from the fracturing tube to the atmosphere is provided on the exhaust port. The exhaust pipe 15 is used to observe whether the liquid oxygen is sufficiently filled.

[0038] Furthermore, an annular groove is provided on one side of the end plate 12 facing the abutment 11, and a sealing ring 13 is provided in the annular groove. When the abutment 11 is connected to the fracturing tube, the upper end of the fracturing tube abuts against the sealing ring 13 to seal the upper end of the fracturing tube.

[0039] Preferably, fastening bolts are provided around the enclosure 11 in the circumferential direction, the fastening bolts are threadedly connected to the enclosure 11 and the fracturing tube, and blind holes are formed on the fracturing tube to avoid puncturing the fracturing tube and affecting the sealing performance.

[0040] Furthermore, a protective ring 14 is provided on a side of the end plate 12 away from the enclosure 11 , both ends of the protective ring 14 are open, and the ports of the protective ring 14 are fixedly connected to the end plate 12 . The aforementioned air inlet, exhaust port and threading port 19 are located within the protective range formed by the protective ring 14 .

[0041] Preferably, the protective ring 14 is square or circular, and is integrally formed with the end plate 12 and the enclosure plate 11 , and is all made of a semi-rigid material, such as PE material.

[0042] In the present application, the protective ring 14 can prevent the infusion tube, the cable and the exhaust tube 15 from being bent at a large angle, thereby preventing the tube from breaking or being blocked by the bending.

[0043] A gap will be generated between the infusion tube and the liquid inlet during the assembly process, and for this reason, the present application also optimizes the liquid inlet. Specifically, the liquid inlet is a threaded hole, and a two-way quick connector 17 is screwed on the liquid inlet. The two-way quick connector 17 has two ends, one end of which is located inside the fracturing tube, and the other end is located outside the fracturing tube. The end located inside the fracturing tube is connected to the infusion tube of the oxygen absorbing medium, and the end located outside the fracturing tube is connected to the extension tube. The extension tube is used to connect with the liquid oxygen supply device, so that the liquid oxygen enters the fracturing tube through the extension tube, the two-way quick connector 17 and the infusion tube, and is absorbed by the oxygen absorbing medium.

[0044] The preferred two-way quick connector 17 further includes a nut 18 for fixing the two-way quick connector 17. The two nuts 18 are respectively threaded with the two-way quick connector 17, and the two nuts 18 are respectively located on the upper and lower sides of the end plate 12. Another sealing ring 13 is provided between the nut 18 and the end plate 12.

[0045] Furthermore, the threading opening 19 is a double-concave threading opening 19 , and the diameters of the threading opening 19 on the upper and lower surfaces of the end plate 12 are larger than the diameter of the threading opening 19 on the middle surface of the end plate 12 , and the middle surface is located between the upper surface and the lower surface of the end plate 12 .

[0046] Preferably, the double-concave threading opening 19 can be sealed by dripping glue after the cable is passed through, and the sealant is concentrated in the threading opening 19 to avoid leakage.

[0047] The present application also provides a method for manufacturing an upper end cover, comprising the following steps:

[0048] S10. Cast a batch of upper end caps, which have an end cap body 10 and reaction petals 20. It should be noted that the length direction of the reaction petals 20 is parallel to the axial direction of the end cap body 10. For the convenience of expression, the end of the reaction petal 20 fixed on the end plate 12 is defined as the fixed end, and the end of the reaction petal 20 away from the end plate 12 is defined as the free end.

[0049] Bend one of the reaction petals 20 at the upper end to any angle, ensuring that the free end of the reaction petal 20 can contact the inner wall of the blast hole after being bent outward. Measure the following parameters of the upper end cover: the radius difference between the outermost radius of the reaction petal 20 and the radius of the test blast hole, the outer diameter of the virtual circle formed by the bottom ends of several reaction petals 20 on the end cover body 10, the inner diameter of the virtual circle formed by the bottom ends of several reaction petals 20 on the end cover body 10, the length of the reaction petal 20, and the number of reaction petals 20;

[0050] S20. Drill multiple blastholes in the area to be fractured, including a test blasthole. Since the multiple blastholes are located in the same area, it is assumed that the friction coefficients of the inner walls of the blastholes are the same.

[0051] The upper end cover is placed in the test blast hole so that the free end contacts the inner wall of the test blast hole, and the sliding friction force exerted on the upper end cover in the test blast hole is measured using a tensile tester.

[0052] S30. Based on the cantilever beam model, the proportional relationship between the sliding friction force and the elastic modulus of the reaction petals 20 and the friction coefficient between the reaction ring plate and the inner wall of the borehole is obtained.

[0053] The cantilever beam model is:

[0054]

[0055] In the formula, f is the sliding friction force between the upper end cover and the blast hole, E is the elastic modulus of the upper end cover, μ is the friction coefficient between the upper end cover and the blast hole, y is the radius difference between the outermost radius of the reaction petal 20 and the radius of the test blast hole, R is the outer diameter of the virtual circle formed by the bottom ends of several reaction petals 20 on the end cover body 10, r is the inner diameter of the virtual circle formed by the bottom ends of several reaction petals 20 on the end cover body 10, L is the length of the reaction petal 20, and n is the number of reaction petals 20.

[0056] Among them, the sliding friction force f is obtained by a tensioner, the radius difference y between the outermost radius of the reaction petal 20 and the radius of the test blast hole, the outer diameter R of the virtual circle formed by the bottom of the reaction petal 20 on the end cover body 10, the inner diameter r of the virtual circle formed by the bottom ends of several reaction petals 20 on the end cover body 10, the length L of the reaction petal 20, and the number n of the reaction petals 20 are all obtained by the upper end cover, and K=Eμ is set at the same time.

[0057] The proportional relationship between sliding friction and K can be obtained from the cantilever beam model.

[0058] S40. Obtain the sliding friction force f1 of the upper end cover installed in the blast hole, obtain the radius difference between the outermost radius of the reaction petal 20 and the radius of the installation blast hole, and obtain the angle α that the reaction petal 20 needs to deflect.

[0059] Specifically, the sliding friction force is obtained, which is the sliding friction force of the blasthole to which the end cover needs to be installed, and can be obtained by using a tensioner. Since the outer diameter R of the virtual circle formed by the bottom of the reaction petal 20 on the end cover body 10, the inner diameter r of the virtual circle formed by the bottom of a plurality of reaction petals 20 on the end cover body 10, the length L of the reaction petal 20, and the number n of the reaction petals 20 are all fixed, the outermost radius R of the reaction petal 20 can be inferred by the cantilever beam model. 外 The radius R of the test hole 孔 The radius difference y.

[0060] Furthermore, due to the aperture R of the blasthole 孔 It can be measured and obtained, and the outermost radius R of the reaction petal 20 can be obtained 外 , R外 =R 炮 -y.

[0061] Based on the sine function Sinα=R 外 / L obtains the deflection angle α of the reaction petal 20.

[0062] S50. A hot pressing mold is manufactured based on the deflection angle of the reaction petals 20 , and the upper end cover is placed in the hot pressing mold to deflect the reaction petals 20 to an angle α.

[0063] S60. After the upper end cover is cooled, a hole is drilled on the end plate 12 to obtain

[0064] The above is a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. An upper end cover of a liquid oxygen fracturing pipe suitable for underwater rock mass, characterized in that: include: An end cover body (10), wherein the upper surface of the end cover body (10) is provided with reaction petals (20), wherein the reaction petals (20) are arranged in a ring on the upper surface of the end cover body (10), wherein the reaction petals (20) form an acute angle α with the axial direction of the end cover body (10), wherein the reaction petals (20) are made of a semi-rigid material, and wherein the end cover body (10) is used for being detachably connected to a fracturing tube.

2. The upper end cover of the liquid oxygen fracturing pipe suitable for underwater rock mass according to claim 1, characterized in that: The end cover body (10) comprises a surrounding plate (11) and an end plate (12), wherein the end plate (12) is arranged above the surrounding plate (11) so that the end cover body (10) forms a semi-enclosed structure, and the surrounding plate (11) is used for being detachably connected to the fracturing pipe; The end plate (12) is provided with a liquid inlet, an exhaust port and a threading port (19). The liquid inlet is used for passing a liquid infusion tube of an oxygen absorbing medium, the exhaust port is provided with an exhaust pipe (15) or a one-way valve (16) allowing liquid oxygen to flow from the inner cavity of the fracturing tube to the atmosphere, and the threading port (19) is used for passing a cable of an electronic excitation device.

3. The upper end cover of the liquid oxygen fracturing pipe suitable for underwater rock mass according to claim 2, characterized in that: A ring groove is provided on one side of the end plate (12) facing the enclosure plate (11), and a sealing ring (13) is provided in the ring groove; When the enclosure plate (11) is connected to the fracturing tube, the upper end of the fracturing tube abuts against the sealing ring (13).

4. The upper end cover of the liquid oxygen fracturing pipe suitable for underwater rock mass according to claim 2, characterized in that: A protective ring (14) is provided on one side of the end plate (12) away from the enclosure plate (11), and the liquid inlet, the exhaust port and the threading port (19) are located within the protective range formed by the protective ring (14).

5. The upper end cover of the liquid oxygen fracturing pipe suitable for underwater rock mass according to claim 2, characterized in that: The liquid inlet is a threaded hole, and a two-way quick connector (17) is threadedly connected to the liquid inlet. One end of the two-way quick connector (17) located inside the fracturing tube is used to communicate with the infusion tube of the oxygen absorption medium, and the other end of the two-way quick connector (17) located outside the fracturing tube is used to communicate with the extension tube.

6. The upper end cover of the liquid oxygen fracturing pipe suitable for underwater rock mass according to claim 2, characterized in that: The threading opening (19) is a double-concave threading opening (19), the diameters of the threading opening (19) on the upper and lower surfaces of the end plate (12) are larger than the diameter of the threading opening (19) on the middle surface of the end plate (12), and the middle surface is located between the upper surface and the lower surface of the end plate (12).

7. A manufacturing method for manufacturing the upper end cover of the liquid oxygen fracturing tube suitable for underwater rock mass as claimed in claim 1, characterized in that: include: S10. Cast a batch of upper end covers, and bend the reaction petals (20) of one of the upper end covers to any angle, and measure the following parameters of the upper end covers: the radius difference between the outermost radius of the reaction petals (20) and the radius of the test blasthole, the outer diameter of the virtual circle formed by the bottom ends of several reaction petals (20) on the end cover body (10), the inner diameter of the virtual circle formed by the bottom ends of several reaction petals (20) on the end cover body (10), the length of the reaction petals (20), and the number of reaction petals (20); S20. Place the upper end cover in the test blast hole and measure the sliding friction force of the upper end cover in the test blast hole using a tensile tester; S30. Based on the cantilever beam model, the proportional relationship between the sliding friction force and the elastic modulus of the reaction force petals (20) and the product of the friction coefficient of the reaction force petals (20) and the hole wall is obtained; S40. Confirm the sliding friction of the blast hole where the upper end cover needs to be installed, obtain the radius difference between the outermost radius of the reaction petal (20) and the radius of the installation blast hole, and obtain the angle α at which the reaction petal (20) needs to be deflected.

8. The method for manufacturing the upper cover according to claim 7, characterized in that: The cantilever beam model is: Wherein, f is the sliding friction force between the upper end cover and the blast hole, E is the elastic modulus of the upper end cover, μ is the friction coefficient between the upper end cover and the blast hole, y is the radius difference between the outermost radius of the reaction petal (20) and the radius of the test blast hole, R is the outer diameter of a virtual circle formed by the bottom ends of a plurality of reaction petals (20) on the end cover body (10), r is the inner diameter of a virtual circle formed by the bottom ends of a plurality of reaction petals (20) on the end cover body (10), L is the length of the reaction petal (20), and n is the number of reaction petals (20).

9. The method for manufacturing an upper cover according to claim 7, characterized in that: In steps S10-S30, the product of the elastic modulus E of the upper end cover and the friction coefficient μ between the upper end cover and the borehole is calculated, and the deflection angle α of the reaction petal (20) is calculated by combining the sine function and the radius difference y between the outermost radius of the reaction petal (20) and the radius of the test borehole.

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