Ultrahigh-temperature acid-resistant soluble bridge plug and setting fracturing method

Abstract

The invention belongs to the technical field of downhole tools, and particularly relates to an ultrahigh-temperature acid-resistant soluble bridge plug and a setting fracturing method. The ultra-high-temperature acid-resistant soluble bridge plug comprises a central pipe, a lower cone, a lower slip and a guide shoe slip fixing seat which are coaxially arranged in sequence, a rubber sleeve is arranged outside the central pipe, a plasma arc driven by direct current is adopted as a heat source, a material containing tungsten carbide as a main body is heated to a molten or semi-molten state, and the guide shoe slip fixing seat is formed. And the tungsten carbide coating is arranged on the inner and outer surfaces of the central pipe, the lower cone, the lower slip and the guide shoe slip fixing seat in a spraying manner, so that the tungsten carbide coating is formed. The method can be suitable for a harsh stratum environment.

Description

Technical Field

[0001] The present invention belongs to the technical field of downhole tools, and in particular, relates to an ultra-high temperature acid-resistant soluble bridge plug and a setting fracturing method. Background Art

[0002] At present, soluble bridge plugs have been widely used for formation isolation in the process of oil and gas well operation. Using bridge plugs for formation isolation can effectively achieve staged fracturing. With the increase of drilling depth of oil and gas wells, the requirements for soluble bridge plugs are getting higher and higher. Taking shale oil and gas wells in some areas as an example, during the operation, the tight oil reservoir is as high as 6000-8000m, and the depth of some blocks is even more than 8000m. There are reservoir characteristics such as ultra-high temperature of 150℃-200℃ and high pressure of 70-100MPa of formation fracture pressure.

[0003] Due to the dense formation and extremely high fracture pressure, after the bridge plug is used to seal the layer section and before the formal fracturing, a complex fracturing process using carbon dioxide, acid, etc. to pre-treat the formation is required. In this environment, higher requirements are placed on the bridge plug, which is required to have characteristics such as resistance to ultra-high temperature, acid corrosion, high pressure and solubility.

[0004] Chinese patent document CN112620055A discloses a hydrochloric acid resistant soluble bridge plug and its preparation method and application. The preparation method includes the following steps: preparing a soluble bridge plug, performing micro-arc oxidation treatment on the surface of the soluble bridge plug; coating the surface of the soluble bridge plug treated with micro-arc oxidation with hydrochloric acid resistant paint; filling the gap between the slip seat and the slip teeth in the soluble bridge plug with epoxy glue, and solidifying the epoxy glue. This application performs micro-arc oxidation treatment on the surface of the soluble bridge plug to form a micro-arc oxidation layer on its surface, and then seals the micropores formed after micro-arc oxidation by coating hydrochloric acid resistant paint, and fills the gap between the slip seat and the slip teeth with epoxy resin, so that the application has hydrochloric acid resistance and can meet the needs of oil fracturing construction.

[0005] Chinese patent document CN111484579A discloses a high-temperature soluble bridge plug and its preparation method. The preparation method includes the following steps: 1) taking butadiene and maleic anhydride, adding an anti-gelling agent, adding diisocyanatobutyronitrile dissolved in DMF as an initiator, adding KH570 as a coupling agent, and using DMF as a solvent; heating in a constant temperature oil bath under nitrogen protection, and fully reflux reaction at 140-180°C; 2) centrifugally washing the solid-liquid mixture after the above reaction, vacuum drying, and the obtained light yellow solid is the raw material for the high-temperature soluble bridge plug; the obtained raw material is thermoformed into a high-temperature soluble bridge plug using a mold. The invention makes full use of the copolymer synthesized from maleic anhydride and butadiene, which has the characteristics of high temperature resistance, pressure resistance, and water solubility, and finally degrades into water and carbon dioxide, reducing the backflow process, and is a biodegradable and environmentally friendly material. This high-temperature soluble bridge plug can be used in the development of unconventional gas reservoirs such as shale gas. The liquid in the well makes the high-temperature soluble bridge plug dissolve by itself, without the need for wellbore drilling and grinding operations and backflow treatment, and the full-bore production of the wellbore can be realized. This patent uses high-molecular organic matter as the base material of the bridge plug, which has acid and high temperature resistance, but its strength is lower than that of the magnesium alloy currently used in the market, especially in high temperature environments, where the strength decreases rapidly, so it is currently rarely used in the market and is still in the experimental stage. Summary of the invention

[0006] In view of the technical problems mentioned above, the present invention aims to provide an ultra-high temperature acid-resistant soluble bridge plug, which can be applied to harsh formation environments.

[0007] The present invention also provides a sealing and fracturing method, which uses the ultra-high temperature acid-resistant soluble bridge plug provided by the present invention to perform sealing and fracturing.

[0008] According to the present invention, there is provided an ultra-high temperature acid-resistant soluble bridge plug, comprising:

[0009] The central tube, the lower cone, the lower slip and the guide slip fixing seat are coaxially arranged in sequence, and a rubber cylinder is arranged outside the central tube.

[0010] A plasma arc driven by direct current is used as a heat source to heat a material mainly containing tungsten carbide to a molten or semi-molten state, and is then sprayed on the inner and outer surfaces of the central tube, the lower cone, the lower slip and the guide slip fixing seat to form a tungsten carbide coating.

[0011] In a preferred embodiment, a molten or semi-molten material containing tungsten carbide as the main body is sprayed onto the inner and outer surfaces of the center tube, the lower cone, the lower slip and the guide slip fixing seat at a spray speed higher than 150m / s to form a tungsten carbide coating.

[0012] In a preferred embodiment, an acid-resistant resin breakable protective film is provided on the lower slip.

[0013] In a preferred embodiment, the dissolved acid-resistant resin liquid is sprayed on the lower slip by a spray gun.

[0014] In a preferred embodiment, a plurality of slip anchoring teeth are provided on the outer wall of the lower slip.

[0015] In a preferred embodiment, at least four circles of the slip anchoring teeth are provided on the outer wall of the lower slip, and the slip anchoring teeth are made of high-strength ceramic particles.

[0016] In a preferred embodiment, a metal support ring is provided on the central tube, and a lower rubber cylinder protection ring is provided between the metal support ring and the rubber cylinder.

[0017] In a preferred embodiment, a floating rubber sleeve shoulder ring is provided at one end of the rubber sleeve away from the metal support ring.

[0018] According to the present invention, a sealing fracturing method is also proposed, which uses the ultra-high temperature acid-resistant soluble bridge plug proposed by the present invention to perform sealing, comprising the following steps:

[0019] Step A: Within 48 hours before the ultra-high temperature acid-resistant soluble bridge plug is lowered into the oil and gas well, a well clearing gauge of the corresponding size or larger is used to clear the well or simulate pumping;

[0020] Step B: Send the ultra-high temperature acid-resistant soluble bridge plug into the well through the adapter, and control the vertical section running speed at 50-70 m / min and the horizontal section running speed at 35-40 m / min;

[0021] Step C: After the ultra-high temperature acid-resistant soluble bridge plug is put into place, it is set;

[0022] Step D: Put the fracturing ball in 30 minutes before fracturing, with a speed of 3 to 4 m 3 / min pumping displacement will pump the fracturing ball into place. When the pumping liquid volume difference is 10m 3 When the casing capacity is reached, the pumping displacement is increased from 3 to 4 m 3 / min down to 1.5~2m 3 / min, fracturing after the ball is seated.

[0023] In a preferred embodiment, the fracturing operation is performed within 12 to 18 hours after the ultra-high temperature acid-resistant soluble bridge plug is set. If the fracturing operation is delayed, 1 to 1.5 times the wellbore volume of clean water can be pumped in to reduce the chloride concentration in the wellbore.

[0024] Compared with the prior art, the present application has at least the following advantages.

[0025] The present invention sprays a tungsten carbide coating mainly containing tungsten carbide as a soluble corrosion-inhibiting particle coating on the inner and outer surfaces of the guide slipper fixing seat, the lower slip, the lower cone and the center tube by spraying. The lower slip is additionally sprayed with an acid-resistant resin breakable protective film on the tungsten carbide coating. The former can improve the acid resistance of the bridge plug, and the latter acid-resistant resin breakable protective film can protect the present invention from reacting with the well fluid within 24 hours, so that the bridge plug can perform sealing operations in high temperature, high pressure and acidic environments. After 24 hours, the protective film falls off, the bridge plug reacts quickly with the well fluid, and the working efficiency of the ultra-high temperature acid-resistant soluble bridge plug is improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] The present invention will be described below with reference to the accompanying drawings.

[0027] Figure 1 A schematic diagram showing an embodiment of an ultra-high temperature acid-resistant soluble bridge plug according to the present invention;

[0028] Figure 2 shows a schematic diagram of a sprayed tungsten carbide coating according to the present invention;

[0029] Figure 3 A schematic structural diagram showing the connection between the ultra-high temperature acid-resistant soluble bridge plug and the adapter of the present invention.

[0030] In the figure:

[0031] 1. Center tube; 2. Rubber cylinder; 3. Metal support ring; 4. Lower cone; 5. Lower slip; 6. Guide shoe slip fixing seat; 7. Slip anchoring teeth; 8. Lower rubber cylinder protection ring; 9. Threaded connection sleeve; 10. Floating rubber cylinder shoulder ring; 11. Tungsten carbide coating; 12. Large diameter part; 13. Small diameter part; 14. Adapter push cylinder; 15. Adapter connecting rod; 16. Setting and releasing sliding sleeve; 17. Upper anti-setting and sealing sleeve; 18. Locking spring; 19. Lower anti-setting and sealing sleeve; 100. Ultra-high temperature acid-resistant soluble bridge plug.

[0032] In the present application, all drawings are schematic drawings, which are only used to illustrate the principles of the present invention and are not drawn according to the actual scale. DETAILED DESCRIPTION

[0033] The present invention will be described below with reference to the accompanying drawings.

[0034] It should be noted that the directional terms or qualifiers "left", "right", etc. used in this application are all relative to the referenced Figure 1 They are not intended to define the absolute positions of the components involved, but may vary depending on the specific circumstances.

[0035] Figure 1 The structure of the ultra-high temperature acid-resistant soluble bridge plug 100 is shown. Figure 1As shown, the ultra-high temperature acid-resistant soluble bridge plug 100 includes a central tube 1, a lower cone 4, a lower slip 5 and a guide slip fixing seat 6 which are coaxially arranged in sequence, and a rubber sleeve 2 is arranged outside the central tube 1.

[0036] The central pipe 1 is connected to the lower cone 4 through threads, the lower slip 5 is connected to the lower cone 4 through a conical surface, and the lower slip 5 is connected to the guide shoe slip fixing seat 6 through threads.

[0037] Combination Figure 1 and Figure 2 As shown, tungsten carbide coatings 11 are provided on the inner and outer surfaces of the central tube 1, the lower cone 4, the lower slip 5 and the guide slip fixing seat 6.

[0038] Specifically, in this embodiment, the tungsten carbide coating 11 mainly containing tungsten carbide is sprayed as a soluble corrosion-inhibiting particle coating, which can improve the acid resistance of the ultra-high temperature acid-resistant soluble bridge plug 100.

[0039] According to the present invention, the method for spraying the tungsten carbide coating 11 is as follows: a plasma arc driven by direct current is used as a heat source to heat a material mainly containing tungsten carbide to a molten or semi-molten state, and the tungsten carbide is set on the inner and outer surfaces of the central tube 1, the lower cone 4, the lower slip 5 and the guide shoe slip fixing seat 6 by spraying, thereby forming a tungsten carbide coating 11.

[0040] Further, a molten or semi-molten material containing tungsten carbide as the main component is sprayed onto the inner and outer surfaces of the central tube 1, the lower cone 4, the lower slip 5 and the guide slip fixing seat 6 at a spraying speed higher than 150 m / s to form a tungsten carbide coating 11, and the thickness of the tungsten carbide coating 11 is set to 0.5-1.0 mm. Among them, the content of tungsten carbide in the material containing tungsten carbide as the main component is higher than 95%.

[0041] In a preferred embodiment, an acid-resistant resin fracture-resistant protective film is provided on the lower slip 5. The lower slip 5 is anchored by the slip anchoring teeth 7. In order to ensure the bite ability and stability of the lower slip 5, it is necessary to slow down the solubility rate of the lower slip 5, so an acid-resistant resin fracture-resistant protective film is provided on the lower slip 5. It is easy to understand that the specific components of the acid-resistant resin fracture-resistant protective film are prior art, which are not the technical points of the present invention and will not be repeated here. The acid-resistant resin fracture-resistant protective film can prevent the lower slip 5 from directly contacting the well fluid. The acid-resistant resin fracture-resistant protective film can protect the lower slip 5 from reacting with the well fluid within 24 hours. After 24 hours, the acid-resistant resin fracture-resistant protective film falls off, and the lower slip 5 reacts quickly with the well fluid.

[0042] In a specific embodiment, the dissolved acid-resistant resin liquid is sprayed on the lower slip 5 by a spray gun to form an acid-resistant resin breakable protective film.

[0043] The ultra-high temperature acid-resistant soluble bridge plug 100 can perform sealing operations under high temperature, high pressure and acidic environments, and can dissolve after a certain period of time, thereby improving work efficiency.

[0044] A plurality of slip anchoring teeth 7 are provided on the outer wall of the lower slip 5. In a preferred embodiment, as Figure 1 As shown, at least four circles of slip anchoring teeth 7 are arranged on the outer wall of the lower slip 5, and the slip anchoring teeth 7 are made of high-strength ceramic particles.

[0045] In a preferred embodiment, the lower slip 5 and the slip anchoring teeth 7 are made of high-strength ceramic particles of 8×5mm or 9.5×7.5mm. After the lower slip 5 is dissolved, the insoluble matter remaining in the well is less than 2%, thereby achieving the effect of facilitating the dissolution of the bridge plug.

[0046] In this embodiment, the central pipe 1 and the guide slip fixing seat 6 are made of 7050 aluminum alloy. Under this setting, the ultra-high temperature acid-resistant soluble bridge plug 100 can withstand a pressure of 70MPa and a temperature range of 150℃ to 200℃, and can withstand pressure, dissolve quickly and completely dissolve within 6 to 10 days after construction in a complex wellbore environment.

[0047] In a preferred embodiment, the thickness of the tungsten carbide coating 11 is set to 0.5-1.0 mm. The tungsten carbide coating 11 prevents the central tube 1, the lower cone 4, the lower slip 5 and the guide slip fixing seat 6 from reacting with 15% hydrochloric acid within 8 hours, delays the reaction time of the 7050 aluminum alloy with hydrochloric acid, improves the sealing efficiency, and enables the bridge plug to achieve the purpose of ultra-high temperature resistance and acid corrosion resistance.

[0048] In a preferred embodiment, an external thread is provided on the outer wall of the central tube 1 , and the lower cone 4 is connected to the external thread of the central tube 1 .

[0049] Furthermore, if Figure 1 As shown, the center pipe 1 includes a large diameter portion 12 and a small diameter portion 13, and a threaded connection sleeve 9 is provided on the right outer wall of the small diameter portion 13 of the center pipe 1 through a thread, and the lower cone 4 is threadedly connected to the center pipe 1 through the threaded connection sleeve 9. When the bridge plug is set, the lower cone 4 and the center pipe 1 will slide relative to each other, compressing the rubber cylinder 2, so that the lower cone 4 and the rubber cylinder 2 are completely pressed, and the threaded connection sleeve 9 only allows the lower cone 4 to move in one direction relative to the center pipe 1, completing self-locking and preventing the lower cone 4 and the center pipe 1 from separating.

[0050] The central pipe 1 and the lower slip 5 are connected into an integrated structure, which is conducive to increasing the effective diameter of the soluble bridge plug, ensuring that the fluid in the well is discharged quickly and without throttling, and improving the efficiency of fracturing after setting. Because before and during the lowering process, due to the size of the setting release tool, the inner diameter of the guide slip fixing seat 6 needs to be made relatively small. Once the release is successful, the guide slip fixing seat 6 with a smaller inner diameter will be separated from the upper part of the bridge plug body, so that the effective inner diameter of the overall soluble bridge plug after setting will become larger.

[0051] In a preferred embodiment, the outer walls of both axial ends of the rubber cylinder 2 are tapered. One end of the rubber cylinder 2 extends into the large diameter portion 12 , and the axial end surface and radial outer wall of the rubber cylinder 2 abut against the large diameter portion 12 .

[0052] A metal support ring 3 is provided on the center tube 1, and the metal support ring 3 is provided at one end of the rubber tube 2 away from the large diameter portion 12. The shape of the metal support ring 3 is adapted to the shape of the rubber tube 2, so that the axial end face and the radial outer wall of the rubber tube 2 are both in contact with the metal support ring 3. A lower rubber tube protection ring 8 is provided between the metal support ring 3 and the rubber tube 2, and the shape of the lower rubber tube protection ring 8 is also adapted to the contact surface between the metal support ring 3 and the rubber tube 2.

[0053] In a preferred embodiment, a floating rubber sleeve shoulder ring 10 is provided at one end of the rubber sleeve 2 away from the metal support ring 3, that is, at the end close to the large diameter portion 12. The axial left end of the floating rubber sleeve shoulder ring 10 abuts against the large diameter portion, and the inner wall of the floating rubber sleeve shoulder ring 10 is set to a shape that matches the cone at the end of the rubber sleeve 2.

[0054] The ultra-high temperature acid-resistant soluble bridge plug 100 can perform seating, isolation, and sealing pressure-bearing operations in an acidic environment with an ultra-high temperature formation temperature of more than 150°C, a high-pressure working pressure difference of 70MPa, and a hydrochloric acid concentration of 10% or less, thereby providing a safe and efficient interlayer isolation guarantee for ultra-high temperature and dense layers that require ultra-high temperature, high pressure, and acid treatment of the formation, improving the working efficiency of the ultra-high temperature acid-resistant soluble bridge plug, while not affecting the normal dissolution of the soluble bridge plug after the fracturing is completed, and ensuring the normal channel for drainage and production after fracturing.

[0055] According to the present invention, a sealing and fracturing method is also provided, which uses the ultra-high temperature acid-resistant soluble bridge plug 100 proposed according to the present invention to perform sealing and fracturing, and includes the following steps.

[0056] Step A: Within 48 hours before the ultra-high temperature acid-resistant soluble bridge plug 100 is lowered into the oil and gas well, a well clearing gauge of a size corresponding to the oil and gas well or larger is used to clear the well or simulate pumping.

[0057] Step B: Send the ultra-high temperature acid-resistant soluble bridge plug 100 into the well through the adapter, and control the vertical well section entry speed at 50-70 m / min and the horizontal section entry speed at 35-40 m / min.

[0058] The connection structure between the adapter and the ultra-high temperature acid-resistant soluble bridge plug 100 is as follows: Figure 3 The adapter includes an adapter push tube 14 and an adapter connecting rod 15. The guide shoe slip fixing seat 6 of the ultra-high temperature acid-resistant soluble bridge plug 100 is connected to the right part of the adapter connecting rod 15, and the right end of the adapter push tube 14 is connected to the left end of the central pipe 1 of the ultra-high temperature acid-resistant soluble bridge plug 100.

[0059] 1) First, remove the lower end of the adapter connecting rod 15 ( Figure 3 The lower anti-seating locking sleeve 19 of the right end of the middle adapter 15 is withdrawn from the locking and fixing thread and is in a free sliding state;

[0060] 2) Insert the guide shoe slip fixing seat 6 into the lower end of the adapter connecting rod 15 and put it in a free state;

[0061] 3) Install the setting release sliding sleeve 16 into the adapter connecting rod 15 from below the guide shoe slip fixing seat 6, align it with the setting release shear pin hole, and tighten the setting release shear pin;

[0062] 4) Push the guide shoe slip fixing seat 6 to the lower end, match it with the setting seal release sliding sleeve 16, and then tighten the lower anti-seating seal locking sleeve 19 through the thread, so that the lower end of the lower anti-seating seal locking sleeve 19 abuts against the guide shoe slip fixing seat 6; 5) Then install the lower slip 5 and the bridge plug body from the upper end of the adapter connecting rod 15;

[0063] 6) Install the anti-seating lock sleeve 17, screw it in from the upper end of the adapter connecting rod 15, until it is completely locked, and tighten it with a special hand tool;

[0064] 7) Screw the three-turn locking spring 18 into the adapter connecting rod 15 through the thread and completely press the anti-seating locking sleeve 17.

[0065] Step C: After the adapter and the ultra-high temperature acid-resistant soluble bridge plug 100 are put into place, they are sealed.

[0066] The adapter and the ultra-high temperature acid-resistant soluble bridge plug 100 are normally lowered into the vertical well section at a speed of 50-70 m / min, and the horizontal section at a speed of 35-40 m / min. In another embodiment, the horizontal section is lowered at a speed of 35-50 m / min.

[0067] If the ultra-high temperature acid-resistant soluble bridge plug 100 is stuck during the lowering process, the cable can be lifted to the safe tension that the cable can withstand to release the blockage. If the ultra-high temperature acid-resistant soluble bridge plug 100 cannot be lifted to loosen, a high concentration (10-15%) potassium chloride aqueous solution or 5-15% hydrochloric acid is injected to quickly dissolve the ultra-high temperature acid-resistant soluble bridge plug 100. After the ultra-high temperature acid-resistant soluble bridge plug 100 is dissolved or loosened, the pumping pipe string is removed for inspection. If the ultra-high temperature acid-resistant soluble bridge plug 100 is set midway and the ignition is lost during the lowering process, high concentration potassium chloride or 5-15% hydrochloric acid can be pumped in to dissolve the ultra-high temperature acid-resistant soluble bridge plug 100. After the dissolution is complete, the plug is probed, and the powder and debris produced by the dissolution are flushed into the lower part, and a new ultra-high temperature acid-resistant soluble bridge plug 100 is re-pumped.

[0068] Step D: Put the fracturing ball in 30 minutes before fracturing, with a speed of 3 to 4 m 3 / min pumping displacement will pump the fracturing ball into place. When the pumping liquid volume difference is 10m 3 When the casing volume of the target layer is reached, the pumping displacement is increased from 3 to 4 m 3 / min down to 1.5~2m 3 / min, fracturing after the ball is seated.

[0069] In this embodiment, after the sealing is completed in step C, the fracturing operation in step D is carried out within 12 to 18 hours. If the fracturing operation is delayed, 1 to 1.5 times the volume of the wellbore can be pumped into the wellbore to reduce the chloride concentration. During the fracturing process, if sand plugging occurs, the return flow rate is controlled to 15m 3 / min, flow back and flush sand. If sand blockage still occurs, run the coiled tubing to flush sand.

[0070] In the description of the present invention, “plurality” means two or more than two, unless otherwise clearly and specifically defined.

[0071] In the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be an indirect connection through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0072] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "examples", "specific examples", or "some examples" means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner.

[0073] Finally, it should be noted that the above is only a preferred embodiment of the present invention and does not constitute any limitation to the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, it is still possible for a person skilled in the art to modify the technical solutions described in the aforementioned embodiments or to replace some of the technical features therein by equivalents. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. An ultra-high temperature acid-resistant soluble bridge plug, characterized in that: include: A central tube (1), a lower cone (4), a lower slip (5) and a guide slip fixing seat (6) are coaxially arranged in sequence, and a rubber sleeve (2) is arranged outside the central tube (1). A plasma arc driven by direct current is used as a heat source to heat a material mainly containing tungsten carbide to a molten or semi-molten state, and is then sprayed on the inner and outer surfaces of the central tube (1), the lower cone (4), the lower slip (5) and the guide slip fixing seat (6), thereby forming a tungsten carbide coating (11).

2. The ultra-high temperature acid-resistant soluble bridge plug according to claim 1, characterized in that: A molten or semi-molten material containing tungsten carbide as the main component is sprayed onto the inner and outer surfaces of the central tube (1), the lower cone (4), the lower slip (5) and the guide slip fixing seat (6) at a spraying speed higher than 150 m / s to form a tungsten carbide coating.

3. The ultra-high temperature acid-resistant soluble bridge plug according to claim 1, characterized in that: An acid-resistant resin breakable protective film is provided on the lower slip (5).

4. The ultra-high temperature acid-resistant soluble bridge plug according to claim 3, characterized in that: The dissolved acid-resistant resin liquid is sprayed onto the lower slip (5) by a spray gun.

5. The ultra-high temperature acid-resistant soluble bridge plug according to any one of claims 1 to 4, characterized in that: A plurality of slip anchoring teeth (7) are arranged on the outer wall of the lower slip (5).

6. The ultra-high temperature acid-resistant soluble bridge plug according to claim 5, characterized in that: At least four circles of slip anchoring teeth (7) are arranged on the outer wall of the lower slip (5), and the slip anchoring teeth (7) are made of high-strength ceramic particles.

7. The ultra-high temperature acid-resistant soluble bridge plug according to any one of claims 1 to 4, characterized in that: A metal support ring (3) is provided on the central tube (1), and a lower rubber cylinder protection ring (8) is provided between the metal support ring (3) and the rubber cylinder (2).

8. The ultra-high temperature acid-resistant soluble bridge plug according to claim 7, characterized in that: A floating rubber sleeve shoulder ring (10) is provided at one end of the rubber sleeve (2) away from the metal support ring (3).

9. A setting fracturing method, characterized in that: The method of setting the ultra-high temperature acid-resistant soluble bridge plug according to any one of claims 1 to 8 comprises the following steps: Step A: Within 48 hours before the ultra-high temperature acid-resistant soluble bridge plug is lowered into the oil and gas well, a well clearing gauge of the corresponding size or larger is used to clear the well or simulate pumping; Step B: Send the ultra-high temperature acid-resistant soluble bridge plug into the well through the adapter, and control the vertical section running speed at 50-70 m / min and the horizontal section running speed at 35-40 m / min; Step C: After the ultra-high temperature acid-resistant soluble bridge plug is put into place, it is set; Step D: Put the fracturing ball in 30 minutes before fracturing, with a speed of 3 to 4 m 3 / min pumping displacement will pump the fracturing ball into place. When the pumping liquid volume difference is 10m 3 When the casing capacity is reached, the pumping displacement is increased from 3 to 4 m 3 / min down to 1.5~2m 3 / min, fracturing after the ball is seated.

10. The setting fracturing method according to claim 9, characterized in that: Fracturing operations should be carried out within 12 to 18 hours after the ultra-high temperature acid-resistant soluble bridge plug is set. If the fracturing operation is delayed, 1 to 1.5 times the wellbore volume of clean water can be pumped in to reduce the chloride concentration in the wellbore.

Images