Open hole segmented well completion soluble fracturing ball and production method and equipment thereof

Abstract

The invention discloses an open hole segmented well completion soluble fracturing ball and a production method and equipment thereof, and the open hole segmented well completion soluble fracturing ball is characterized in that the open hole segmented well completion soluble fracturing ball adopts a ball core and coating structure. The ball core is made of a high-pressure-resistant, high-temperature-resistant and easy-to-corrode material, the coating is made of a high-temperature-resistant, high-pressure-resistant and corrosion-resistant polytetrafluoroethylene nanoparticle modified phenolic resin material, and the thickness of the polytetrafluoroethylene nanoparticle modified phenolic resin material is limited. The pressure stabilization duration of the open hole staged well completion soluble fracturing ball under the given temperature, pressure and acid environment is limited, so that the open hole staged well completion soluble fracturing ball can be rapidly dissolved after meeting the fracturing requirement.

Description

Technical Field

[0001] The present invention relates to the technical field of oil engineering well completion, and more specifically, it relates to a soluble fracturing ball for open-hole segmented well completion, its production method and equipment. Background Technique

[0002] The Shunbei Oilfield belongs to a fault dissolution hydrocarbon reservoir with ultra-deep (>7500 m), high temperature (160 - 180 °C), high pressure (90 - 140 MPa), and extremely strong heterogeneity. In the initial stage of development, the well completion technology was single. The conventional well killing and production induction technology for lost circulation wells or the general acid fracturing well completion technology did not fully utilize the reservoir, resulting in low single-well production and poor development efficiency. The main manifestations included weak correlation in the fracture zone distribution, acid fluid loss to weak points, ineffective transformation of favorable sweet spots, and a sliding sleeve success rate of only 70%. In view of the heterogeneous characteristics of the reservoir, the currently adopted open-hole segmented well completion technology for ultra-deep horizontal wells can relatively effectively release the production capacity of ultra-deep large fracture zones, meet the reservoir development requirements, and achieve the goal of long-term stable production. The soluble fracturing ball plays a key role in the open-hole segmented well completion technology. It needs to be placed in the well at a predetermined time or depth to block the pipeline or wellbore. Since its dissolution requires certain conditions and time, during the dissolution process of the soluble fracturing ball, high-pressure fluid can be pumped to make the pressure accumulate at a specific position in the well to form fractures.

[0003] Currently, the soluble fracturing ball used in the open-hole segmented well completion technology can withstand a pressure of 70 MPa at 80 °C, but its general dissolution time is 10 days or even longer, and the dissolution efficiency is relatively low.

[0004] For the above reasons, the present invention provides a soluble fracturing ball for open-hole segmented well completion, its production method and equipment, which can improve the dissolution efficiency of the soluble fracturing ball on the basis of meeting the downhole pressure-bearing requirements, so that the soluble fracturing ball can dissolve quickly after the fracture is formed for subsequent operations. Summary of the Invention

[0005] To achieve the above object, the present invention provides the following technical solution: A soluble fracturing ball for open-hole segmented well completion, the ball core of the soluble fracturing ball for open-hole segmented well completion is made of any one of wood materials, plastic materials, fiber materials, porous ceramic materials, aluminum, aluminum alloy, magnesium, and magnesium alloy. A layer of polytetrafluoroethylene nanoparticle modified phenolic resin material is evenly coated on the surface of the ball core.

[0006] The present invention is further configured as: Corrosion-resistant and high-temperature-resistant rubber particles are evenly distributed in the polytetrafluoroethylene nanoparticle modified phenolic resin material.

[0007] The present invention is further configured as: The thickness of the polytetrafluoroethylene nanoparticle modified phenolic resin material on the surface of the ball core is 0.4 - 0.6 mm.

[0008] The present invention is further configured such that: the ball core is made of any one of aluminum, aluminum alloy, magnesium, and magnesium alloy.

[0009] The present invention is further configured such that: the ball core is surface-treated before being coated with the polytetrafluoroethylene nanoparticle-modified phenolic resin material. The surface treatment is used to increase the corrosion resistance of the ball core surface, and it includes any one of chemical conversion, anodic oxidation, metal coating, and diffusion coating.

[0010] The present invention is further configured such that: the chemical conversion is any one of chromate conversion, phosphate conversion, phosphate-manganate conversion, and rare earth conversion.

[0011] The present invention is further configured such that: the anodic oxidation is micro-arc anodic oxidation.

[0012] The present invention is further configured such that: the ball core is made of magnesium aluminum alloy.

[0013] The present invention also provides a production method for a soluble fracturing ball for open-hole staged completion: used for producing the above-mentioned soluble fracturing ball for open-hole staged completion, and it includes the following steps: S1. Obtain the ball core.

[0014] S2. Uniformly coat the polytetrafluoroethylene nanoparticle-modified phenolic resin material on the surface of the ball core.

[0015] The present invention is further configured such that: the coating thickness of the polytetrafluoroethylene nanoparticle-modified phenolic resin material is determined through experiments. The experimental steps are as follows: given a qualified interval for the pressure stability duration, test the pressure stability duration of the soluble fracturing ball for open-hole staged completion under a given temperature environment, pressure environment, and acidic environment. If the pressure stability duration is less than the minimum value of the qualified interval for the pressure stability duration, increase the thickness of the polytetrafluoroethylene nanoparticle-modified phenolic resin material; if the pressure stability duration is greater than the maximum value of the qualified interval for the pressure stability duration, reduce the thickness of the polytetrafluoroethylene nanoparticle-modified phenolic resin material until the pressure stability duration is within the qualified interval for the pressure stability duration.

[0016] The present invention is further configured such that: the qualified interval for the pressure stability duration is 6h - 10h.

[0017] The present invention is further configured such that: the ball core in S1 needs to be surface-treated, and during the pressure stability period of the soluble fracturing ball for open-hole staged completion under a given temperature environment, pressure environment, and acidic environment, the strength of the surface-treated ball core remains unchanged.

[0018] The present invention is further configured such that: the ball core is made of magnesium alloy, and its magnesium-aluminum ratio is determined through experiments. Given the qualified limit of the dissolution time, the dissolution time of the open-hole staged completion soluble fracturing ball is tested under a given temperature environment, pressure environment, and acidic environment. If the dissolution time is less than the minimum value of the qualified limit of the dissolution time, the aluminum proportion in the ball core is increased; if the dissolution time is greater than the maximum value of the qualified limit of the dissolution time, the aluminum proportion in the ball core is decreased until the dissolution time is within the qualified limit of the dissolution time.

[0019] The present invention is further configured such that: the qualified limit of the dissolution time is 12 h.

[0020] The present invention also provides an open-hole staged completion soluble fracturing ball production device: it uses the above-mentioned open-hole staged completion soluble fracturing ball production method to produce open-hole staged completion soluble fracturing balls.

[0021] In summary, the present invention has the following beneficial effects compared with the prior art: the open-hole staged completion soluble fracturing ball of the present invention adopts a "ball core + coating" structure. The ball core is made of a material that is easy to corrode and resistant to high pressure and high temperature, and the coating is made of polytetrafluoroethylene nanoparticle-modified phenolic resin material that is resistant to high temperature, high pressure, and corrosion. By limiting the thickness of the polytetrafluoroethylene nanoparticle-modified phenolic resin material, the pressure stability duration of the open-hole staged completion soluble fracturing ball under a given temperature, pressure, and acidic environment is limited, so that the open-hole staged completion soluble fracturing ball can be quickly dissolved after meeting the fracturing requirements. At the same time, the present invention also adds rubber particles to the polytetrafluoroethylene nanoparticle-modified phenolic resin material, increasing the toughness of the polytetrafluoroethylene nanoparticle-modified phenolic resin material and further improving the protection effect of the polytetrafluoroethylene nanoparticle-modified phenolic resin material on the ball core during the process of entering the well and bearing pressure. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 It is a schematic structural diagram of an open-hole staged completion soluble fracturing ball.

[0023] Figure 2 is Figure 1 an enlarged schematic diagram of area A in

[0024] In the figure: 1, ball core; 2, surface treatment; 3, polytetrafluoroethylene nanoparticle-modified phenolic resin material. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0025] The technical solutions of the present invention will be clearly described below in conjunction with the accompanying drawings. Obviously, the described embodiments are not all the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art without creative efforts fall within the protection scope of the invention.

[0026] It should be noted that the orientation or positional relationship indicated by terms such as "center", "upper", "lower", "horizontal", "left", "right", "front", "rear", "lateral", "longitudinal", etc. is based on the orientation or positional relationship shown in the drawings. It is only for the convenience of describing the present invention and simplifying the description, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation to the present invention.

[0027] Embodiment As Figure 1-2 shown, it is a schematic structural diagram of a soluble fracturing ball for open-hole staged completion in a preferred embodiment of the present invention. The ball core 1 of the soluble fracturing ball for open-hole staged completion has the properties of high temperature resistance and high pressure resistance, and is made of any one of wood materials, plastic materials, fiber materials, porous ceramic materials, aluminum, aluminum alloys, magnesium, and magnesium alloys. A layer of polytetrafluoroethylene nanoparticle modified phenolic resin material 3 is evenly coated on the surface of the ball core 1, which has the properties of high pressure resistance and high temperature resistance, and can also effectively improve the corrosion resistance of the ball core 1. By controlling the coating thickness of the polytetrafluoroethylene nanoparticle modified phenolic resin material 3, the pressure stability duration of the soluble fracturing ball for open-hole staged completion under a given temperature, pressure, and acidic environment can be controlled.

[0028] Specifically, corrosion-resistant and high-temperature-resistant rubber particles are evenly distributed in the polytetrafluoroethylene nanoparticle modified phenolic resin material 3. The rubber particles can effectively enhance the toughness of the polytetrafluoroethylene nanoparticle modified phenolic resin material 3 and further improve the protection effect of the polytetrafluoroethylene nanoparticle modified phenolic resin material 3 on the ball core 1 during the process of entering the well and bearing pressure. In this embodiment, the rubber particles are any one of fluororubber particles, silicone rubber particles, and polytetrafluoroethylene rubber particles.

[0029] Specifically, the particle size of the rubber particles is less than or equal to the particle size of the polytetrafluoroethylene nanoparticles in the polytetrafluoroethylene nanoparticle modified phenolic resin material 3 layer to reduce the influence of the rubber particles on the surface roughness of the polytetrafluoroethylene nanoparticle modified phenolic resin material 3 layer.

[0030] Specifically, the thickness of the polytetrafluoroethylene nanoparticle modified phenolic resin material 3 on the surface of the ball core 1 is 0.4 - 0.6 mm.

[0031] Specifically, the ball core 1 is made of any one of aluminum, aluminum alloy, magnesium, and magnesium alloy. The metal ball core 1 is prone to corrosion, and the bonding force between the metal ball core 1 and the polytetrafluoroethylene nanoparticle modified phenolic resin material 3 is low, and it is easy to fall off under the combined action of high-temperature environment and strong corrosive medium impact, which helps to accelerate the dissolution of the open-hole segmented completion soluble fracturing ball. The ball core 11 is preferably made of magnesium alloy, which produces less pollution during the dissolution process, meets the environmental protection requirements, and has a small density of magnesium alloy, which is convenient for transportation. On this basis, in this embodiment, magnesium aluminum alloy in magnesium alloy is selected as the preparation material of the ball core 1 considering comprehensively from aspects such as temperature resistance performance, material strength, processing performance, and degradation ability.

[0032] Specifically, the ball core 1 undergoes surface treatment 2 before being coated with the polytetrafluoroethylene nanoparticle modified phenolic resin material 3. The surface treatment 2 is used to increase the corrosion resistance of the surface of the ball core 1 and reduce the possibility of the ball core 1 being dissolved during the period when the open-hole segmented completion soluble fracturing ball maintains pressure stability in a given temperature environment, pressure environment, and acidic environment. The surface treatment 2 includes any one of chemical conversion, anodic oxidation, metal coating, and diffusion coating.

[0033] Chemical conversion is to form a layer of oxide or metal compound passivation film on the surface of the metal ball core 1 after the metal ball core 1 is immersed in the chemical treatment solution. The chemical conversion is preferably any one of chromate conversion, phosphate conversion, phosphate-manganate conversion, and rare earth conversion. Anodic oxidation is to form a layer of oxide film on the surface of the metal ball core 1 through electrochemical oxidation. The anodic oxidation is preferably a micro-arc anodic oxidation layer. Metal coating is to coat a layer of metal or alloy film on the surface of the metal ball core 1 by a physical method. Diffusion coating is to form a coating with a porous structure on the surface of the metal ball core 1. In this embodiment, the surface treatment 2 selects chemical conversion.

[0034] This embodiment also provides a method for producing an open-hole segmented completion soluble fracturing ball: used for producing the above-mentioned open-hole segmented completion soluble fracturing ball, including the following steps: S1. Obtain the ball core 1.

[0035] S2. Uniformly coat the polytetrafluoroethylene nanoparticle modified phenolic resin material 3 on the surface of the ball core 1.

[0036] Specifically, the coating thickness of the polytetrafluoroethylene nanoparticle-modified phenolic resin material 3 is determined through experiments. The experimental steps are as follows: given a qualified interval for the pressure stabilization duration, the pressure stabilization duration of the open-hole staged completion soluble fracturing ball is tested under a given temperature environment, pressure environment, and acidic environment. If the pressure stabilization duration is less than the minimum value of the qualified interval for the pressure stabilization duration, the thickness of the polytetrafluoroethylene nanoparticle-modified phenolic resin material 3 is increased; if the pressure stabilization duration is greater than the maximum value of the qualified interval for the pressure stabilization duration, the thickness of the polytetrafluoroethylene nanoparticle-modified phenolic resin material 3 is decreased until the pressure stabilization duration is within the qualified interval for the pressure stabilization duration. In this embodiment, the qualified interval for the pressure stabilization duration is 6 h - 10 h, that is, the polytetrafluoroethylene nanoparticle-modified phenolic resin material 3 will age, bulge, and peel off by itself after 6 - 10 h in a high-temperature environment. In this embodiment, the open-hole staged completion soluble fracturing ball can maintain the pressure basically stable for 6 hours in an acidic environment at 160°C and 70 MPa.

[0037] Specifically, the ball core 1 in S1 needs to undergo surface treatment 2, and the strength of the ball core 1 after surface treatment 2 remains unchanged during the pressure stabilization of the open-hole staged completion soluble fracturing ball under a given temperature environment, pressure environment, and acidic environment.

[0038] Specifically, the ball core 1 is made of magnesium alloy, and its magnesium-aluminum ratio is determined through experiments. Given a qualified limit for the dissolution time, the dissolution time of the open-hole staged completion soluble fracturing ball is tested under a given temperature environment, pressure environment, and acidic environment. If the dissolution time is less than the minimum value of the qualified limit for the dissolution time, the aluminum proportion in the ball core 1 is increased; if the dissolution time is greater than the maximum value of the qualified limit for the dissolution time, the aluminum proportion in the ball core 1 is decreased until the dissolution time is within the qualified limit for the dissolution time. In this embodiment, the qualified limit for the dissolution time is 12 h, that is, the open-hole staged completion soluble fracturing ball can be completely dissolved in only 12 h, and this limit is achieved in an acidic environment at 160°C and 70 MPa. In this embodiment, the average dissolution rate of the open-hole staged completion soluble fracturing ball in formation water is 7.19 g / h.

[0039] This embodiment also provides an open-hole staged completion soluble fracturing ball production device: it uses the above-mentioned open-hole staged completion soluble fracturing ball production method to produce open-hole staged completion soluble fracturing balls.

[0040] Taking a well in a super-deep carbonate rock fracture and dissolution pore reservoir as an example, the above-mentioned open-hole staged completion soluble fracturing ball was used for the well completion construction of this well. The open-hole staged completion technology of "suspension packer + high-performance expandable open-hole packer + ball-drop sliding sleeve + fracturing sliding sleeve + soluble fracturing ball" was used for the well completion construction of this well. The construction interval was 7564.0 m - 8659.11 m. The construction string achieved the goal of being divided into three sections. The diameters of the open-hole staged completion soluble fracturing balls used in each section were different. From the smallest distance from the wellhead along the well section, the diameters of the open-hole staged completion soluble fracturing balls decreased in turn. The grade difference between the open-hole staged completion soluble fracturing balls in adjacent sections was 6.35 mm. After the well completion of this well, the total construction fluid volume was 2535 m 3 , the maximum displacement was 10.3 m 3 / min, the maximum pump pressure was 134.8 MPa, and the shut-in pressure was 11.5 MPa. After the well was produced with a 13 mm choke, it was found that when the wellhead pressure was 52.83 MPa, the gas test production of this well was 99.87×104 m 3 / d, the daily oil production was 288 m 3 , and the converted oil and gas equivalent was 1017 t / d.

[0041] In summary, the open-hole staged completion soluble fracturing ball of this embodiment adopts the structure of "ball core 1 + coating". The ball core 1 is made of a material that is easy to corrode and resistant to high pressure and high temperature. The coating is made of polytetrafluoroethylene nanoparticle-modified phenolic resin material 3 that is resistant to high temperature, high pressure, and corrosion. By limiting the thickness of the polytetrafluoroethylene nanoparticle-modified phenolic resin material 3, the pressure stability duration of the soluble fracturing ball in a given temperature, pressure, and acidic environment is limited, so that the open-hole staged completion soluble fracturing ball can dissolve quickly after meeting the fracturing requirements. At the same time, in this embodiment, rubber particles are added to the polytetrafluoroethylene nanoparticle-modified phenolic resin material 3, which increases the toughness of the polytetrafluoroethylene nanoparticle-modified phenolic resin material 3 and further improves the protection effect of the polytetrafluoroethylene nanoparticle-modified phenolic resin material 3 on the ball core 1 during the process of entering the well and bearing pressure.

[0042] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention can have various changes and modifications. 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. A soluble fracturing ball for open-hole staged completion, characterized in that: The ball core (1) of the open-hole segmented completion soluble fracturing ball is made of any one of wood materials, plastic materials, fiber materials, porous ceramic materials, aluminum, aluminum alloy, magnesium, and magnesium alloy; a layer of polytetrafluoroethylene nanoparticle modified phenolic resin material (3) is evenly coated on the surface of the ball core (1).

2. The dissolvable fracturing ball for open-hole staged completion according to claim 1, wherein: Corrosion-resistant and high-temperature-resistant rubber particles are evenly distributed in the polytetrafluoroethylene nanoparticle modified phenolic resin material (3).

3. A dissolvable fracturing ball for open-hole staged completion according to claim 1 or 2, characterized in that: The thickness of the polytetrafluoroethylene nanoparticle modified phenolic resin material (3) on the surface of the ball core (1) is 0.4 - 0.6 mm.

4. A dissolvable fracturing ball for open-hole segmented completion according to claim 1 or 2, characterized in that: The ball core (1) is made of any one of aluminum, aluminum alloy, magnesium, and magnesium alloy.

5. A dissolvable fracturing ball for open-hole staged completion according to claim 4, characterized in that: The ball core (1) is surface-treated (2) before coating the polytetrafluoroethylene nanoparticle modified phenolic resin material (3); the surface treatment (2) is used to increase the corrosion resistance of the surface of the ball core (1), and it includes any one of chemical conversion, anodic oxidation, metal coating, and diffusion coating.

6. The dissolvable fracturing ball for open-hole staged completion according to claim 5, wherein: The chemical conversion is any one of chromate conversion, phosphate conversion, phosphate - permanganate conversion, and rare earth conversion.

7. A soluble fracturing ball for open-hole segmented completion according to claim 5, characterized in that: The anodic oxidation is micro-arc anodic oxidation.

8. A dissolvable fracturing ball for open-hole staged completion according to claim 5, characterized in that: The ball core (1) is made of magnesium aluminum alloy.

9. A production method of a dissolvable fracturing ball for open-hole segmented completion, characterized in that: The method for producing the open-hole segmented completion soluble fracturing ball as claimed in any one of claims 1 - 8 includes the following steps: S1. Obtain the ball core (1); S2. Evenly coat the polytetrafluoroethylene nanoparticle modified phenolic resin material (3) on the surface of the ball core (1).

10. A production method of a soluble fracturing ball for open-hole staged completion according to claim 9, characterized in that: The coating thickness of the polytetrafluoroethylene nanoparticle modified phenolic resin material (3) is determined by experiments. The experimental steps are as follows: Given a qualified interval of pressure stability duration, test the pressure stability duration of the open-hole segmented completion soluble fracturing ball under a given temperature environment, pressure environment, and acidic environment; if the pressure stability duration is less than the minimum value of the qualified interval of pressure stability duration, increase the thickness of the polytetrafluoroethylene nanoparticle modified phenolic resin material (3), and if the pressure stability duration is greater than the maximum value of the qualified interval of pressure stability duration, reduce the thickness of the polytetrafluoroethylene nanoparticle modified phenolic resin material (3) until the pressure stability duration is within the qualified interval of pressure stability duration.

11. A production method of a dissolvable fracturing ball for open-hole staged completion according to claim 10, characterized in that: The qualified interval of pressure stability duration is 6 h - 10 h.

12. A production method of a dissolvable fracturing ball for open-hole staged completion according to claim 10, characterized in that: The ball core (1) in S1 needs to be surface-treated (2), and during the pressure stability of the open-hole segmented completion soluble fracturing ball under a given temperature environment, pressure environment, and acidic environment, the strength of the surface-treated (2) ball core (1) remains unchanged.

13. A production method of a dissolvable fracturing ball for open-hole staged completion according to claim 9, characterized in that: The ball core (1) is made of magnesium aluminum alloy, and its magnesium-aluminum ratio is determined by experiments. Given a qualified limit of dissolution time, test the dissolution time of the open-hole segmented completion soluble fracturing ball under a given temperature environment, pressure environment, and acidic environment. If the dissolution time is less than the minimum value of the qualified limit of dissolution time, increase the aluminum proportion in the ball core (1), and if the dissolution time is greater than the maximum value of the qualified limit of dissolution time, reduce the aluminum proportion in the ball core (1) until the dissolution time is within the qualified limit of dissolution time.

14. A production method of a naked-eye sectional completion soluble fracturing ball according to claim 13, characterized in that: The qualified limit of dissolution time is 12 h.

15. A production device for a dissolvable fracturing ball for open-hole staged completion, characterized in that: The open-hole segmented completion soluble fracturing ball production equipment manufactures the open-hole segmented completion soluble fracturing ball by using the open-hole segmented completion soluble fracturing ball production method as claimed in any one of claims 9 - 14.

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