An acidizing and fracturing experimental core end face anti-scouring protection device

Abstract

The utility model discloses an acidification fracturing experimental core end face anti -scouring protection device belongs to oil and gas field development experimental equipment technical field, solves acidification fracturing core experiment, and the technical problem that experimental liquid directly impacts the core end face through the liquid inlet channel, including experimental core body and protection component, protection component includes end face protection disc, and the end face protection disc is through the core butt joint groove and is equipped in the end of experimental core body, the center of end face protection disc is equipped with assembly and installation groove, and the assembly and installation groove is installed with the flow channel cylinder, in the utility model, the flow channel cylinder is communicated with the inside of core butt joint groove, and one end butt joint core holder liquid inlet channel, and the other end communicates experimental core body center area, and the experimental liquid is oriented and transported to the effect, and the flow of experimental liquid is changed, and the original end face global impact is converted into center area directional transportation, and the scouring pressure of core end face is reduced significantly, and the damage such as the dent, peeling of end face is avoided.

Description

Technical Field

[0001] This utility model relates to the technical field of experimental equipment for oil and gas field development, and in particular to an anti-erosion protection device for the end face of an acid fracturing experimental core. Background Technology

[0002] In oil and gas field development, acid fracturing is a crucial production enhancement measure to improve well yields. Its principle involves injecting acid or fracturing fluid into the reservoir under high pressure, causing fractures in the reservoir rock and improving reservoir permeability, thus creating efficient channels for oil and gas flow. Laboratory experiments, as the core component for evaluating the effectiveness of acid fracturing, serve as a crucial bridge between laboratory research and field operations. Core flow experiments, in particular, with their precise simulation of formation pressure, temperature, and other environmental conditions, have become a core method for exploring the interaction between acid fracturing fluid and the core, and predicting reservoir stimulation effects. Based on Darcy's law, this experiment precisely controls fluid parameters, measures data such as the pressure difference between the core inlet and outlet, and fluid flow rate, and calculates key indicators such as permeability. This provides direct data support for optimizing acid fracturing process parameters and selecting working fluid formulations. The reliability of the data directly determines the scientific validity and rationality of oilfield development plans.

[0003] In existing acid fracturing core experiments, the core is usually held in a core holder. The experimental fluid directly impacts the core end face through the inlet channel and then flows through the core interior. Due to the high pressure and flow rate of the experimental fluid, and the presence of abrasive particles such as sand in some of the fluid, long-term impact can lead to problems such as erosion, wear, and spalling of the core end face. Damage to the core end face will change the original end face morphology and effective flow area, resulting in inaccurate measurement of parameters such as pressure and flow rate during the experiment, thus affecting the reliability of the experimental data. Utility Model Content

[0004] To address the shortcomings of existing technologies, this utility model provides an anti-erosion protection device for the end face of acid fracturing test cores, which solves the technical problem in existing acid fracturing core experiments where the core is held in a core holder and the experimental liquid directly impacts the end face of the core through the inlet channel, leading to erosion, wear, and spalling of the core end face.

[0005] To achieve the above objectives, the technical solution adopted by this utility model is as follows:

[0006] A protective device for preventing erosion of the end face of an acid fracturing experimental core includes an experimental core body with a protective component at its end. The protective component includes an end face protective plate with a core docking groove on one side, through which the end face protective plate is fitted onto the end of the experimental core body. An assembly groove is provided in the center of the end face protective plate, and a flow guide tube is installed in the assembly groove. One end of the flow guide tube is connected to the liquid inlet channel of the core holder, and the other end of the flow guide tube is connected to the central area of ​​the experimental core body.

[0007] In this scheme, the experimental core body serves as the core object of the acid fracturing experiment, simulating the mechanical and seepage characteristics of formation rocks. It acts as the target carrier for the experimental fluid, providing authentic rock samples to support experimental data such as the conductivity and fracture propagation patterns of acid fracturing, ensuring the guiding value of the experimental results for on-site construction. The end-face protection plate, as a direct protective component for the core end face, is fitted onto the end of the experimental core body via a core docking groove. This isolates the experimental fluid from direct contact with the core end face, fundamentally preventing the high-pressure fluid from scouring and eroding the core end face, and solving the problem of experimental data distortion caused by core end face damage. The flow guide tube communicates with the inside of the core docking groove, with one end connecting to the fluid inlet channel of the core holder and the other end connecting to the central area of ​​the experimental core body. It guides and transports the experimental fluid, changing the flow direction of the experimental fluid, transforming the original full-area impact on the end face into directional transport in the central area, significantly reducing the scouring pressure on the core end face and preventing damage such as pitting and spalling.

[0008] Furthermore, an annular sealing ring is installed inside the core docking groove.

[0009] In this scheme, the annular sealing ring seals the gap between the end face protective plate and the experimental core body to prevent the experimental liquid from leaking out of the gap and avoid the leakage liquid from eroding the sidewall of the core.

[0010] Furthermore, an assembly annular groove is provided between the core docking groove and the outer wall of the guide channel cylinder, and an annular sealing ring is set inside the assembly annular groove.

[0011] In this design, the annular groove is used to limit the movement of the annular seal ring, preventing it from falling off.

[0012] Furthermore, a locking threaded hole is provided on the side of the end face protective plate. The locking threaded hole communicates with the interior of the assembly and installation groove. A limit bolt is connected to the internal thread of the locking threaded hole. The end of the limit bolt is grounded on the outer wall of the guide channel cylinder.

[0013] In this solution, after the limiting bolt is screwed in, its end abuts against the surface of the guide channel cylinder, axially limiting and fixing the guide channel cylinder. By pressing and fixing the guide channel cylinder, it is prevented from loosening or falling off under the impact of high-pressure liquid, thus ensuring the continuous stability of the guide function.

[0014] Furthermore, a countersunk bolt hole is provided at the opening of the locking threaded hole, and the head of the limiting bolt is recessed inside the countersunk bolt hole.

[0015] In this design, the countersunk bolt hole design prevents the bolt head from protruding from the end face protective plate surface, thus preventing interference between the bolt head and the core holder's liquid inlet channel, ensuring a tight fit between the holder and the end face protective plate and smooth flow of the liquid channel.

[0016] Furthermore, a spring washer is fitted on the outside of the limiting bolt, and the spring washer is located inside the bolt countersunk hole after the limiting bolt is assembled into the locking thread hole.

[0017] In this design, spring washers enhance the anti-loosening performance of threaded connections. The elastic deformation of the spring washers counteracts vibrations during the experiment, preventing the limit bolts from loosening.

[0018] Furthermore, a protective sleeve is fitted onto the end of the experimental core body that is furthest from the end face protective plate.

[0019] In this design, the protective sleeve and the end face protective plate work together to ensure that the rock core is subjected to uniform force at both ends, preventing eccentric deformation of the rock core under the action of high-pressure experimental liquid and ensuring the consistency of experimental conditions.

[0020] The beneficial effects of this utility model are:

[0021] In the anti-erosion protection device for the end face of the acid fracturing experimental core provided by this utility model, the end face protection plate equipped with the annular sealing ring is aligned with the end of the experimental core body through the core docking groove and slowly put into place, so that the end face protection plate is tightly fitted with the end face of the core. At this time, the annular sealing ring is located in the gap between the end face protection plate and the experimental core body, forming a sealing structure. The experimental core, equipped with protective components, is smoothly placed into the core holder to secure and position it. The relative positions of the inlet channel of the core holder and the guide channel on the end-face protective plate are checked to ensure unobstructed communication, laying the foundation for smooth flow of the experimental liquid. After the experiment starts, the experimental liquid flows out of the inlet channel of the core holder at the preset pressure and flow rate, first precisely entering the guide channel on the end-face protective plate. With the guidance of the guide channel, the experimental liquid is concentrated and transported to the central area of ​​the experimental core, avoiding direct impact of the liquid on the core end face. This reduces the risk of erosion and washout of the core end face, and prevents changes in the original end face shape and effective flow area due to damage. This ensures the accuracy of key parameter measurements such as pressure and flow rate during the experiment and guarantees the reliability of all experimental data. Attached Figure Description

[0022] Figure 1 This is a structural diagram of an anti-erosion protection device for the end face of an acid fracturing experimental rock core according to this utility model;

[0023] Figure 2 This is an exploded view of an anti-erosion protection device for the end face of an acid fracturing experimental rock core according to this utility model;

[0024] Figure 3 This is a structural diagram of the protective disc on the middle end face of this utility model;

[0025] Figure 4 This is an exploded view of the end face protective disc and the annular sealing ring of this utility model;

[0026] Figure 5 This is an exploded view of the end face protection plate and the flow channel cylinder of this utility model.

[0027] Figure label:

[0028] 1. Experimental core body; 2. End face protective plate; 3. Core docking groove; 4. Flow guide tube; 5. Annular sealing ring; 6. Assembly annular groove; 7. Assembly installation groove; 8. Locking threaded hole; 9. Limiting bolt; 10. Bolt countersunk hole; 11. Spring washer; 12. Protective sleeve. Detailed Implementation

[0029] The present invention will be further described below with reference to the accompanying drawings and specific embodiments. The specific embodiments of the present invention are described below to facilitate understanding by those skilled in the art. However, it should be understood that the present invention is not limited to the scope of the specific embodiments. For those skilled in the art, various changes are obvious as long as they fall within the spirit and scope of the present invention as defined and determined by the appended claims. All inventions utilizing the concept of the present invention are protected.

[0030] like Figure 1 As shown, this embodiment provides an anti-erosion protection device for the end face of an acid fracturing experimental core, which solves the technical problem in existing acid fracturing core experiments where the core is held in a core holder and the experimental liquid directly impacts the end face of the core through the inlet channel, leading to erosion, wear, and spalling of the core end face. Specifically, it includes: an experimental core body 1 and a protective component set at the end of the experimental core body 1. The experimental core body 1, as the core object of the acid fracturing experiment, simulates the mechanical and seepage characteristics of the formation rock and is the target carrier of the experimental liquid. It provides real rock sample support for experimental data such as the conductivity of acid fracturing and the fracture propagation law, ensuring the guiding value of the experimental results for on-site construction.

[0031] like Figure 2 As shown, the protective assembly includes an end-face protective plate 2, a flow guide tube 4, an annular sealing ring 5, and a limiting bolt 9. A core docking groove 3 is provided on one side of the end-face protective plate 2, and the end-face protective plate 2 is fitted onto the end of the experimental core body 1 through the core docking groove 3. An assembly and installation groove 7 is provided in the center of the end-face protective plate 2, and the flow guide tube 4 is installed within the assembly and installation groove 7. Figure 5 As shown. One end of the flow channel cylinder 4 is connected to the liquid inlet channel of the core holder, and the other end of the flow channel cylinder 4 is connected to the central area of ​​the experimental core body 1. The end face protection plate 2, as a direct protective component for the core end face, is fitted onto the end of the experimental core body 1 through the core docking groove 3, isolating the experimental liquid from direct contact with the core end face, fundamentally avoiding the scouring and erosion of the core end face by high-pressure liquid, and solving the problem of experimental data distortion caused by core end face damage. The flow channel cylinder 4 is internally connected to the core docking groove 3, with one end connected to the liquid inlet channel of the core holder and the other end connected to the central area of ​​the experimental core body 1, playing a guiding and conveying role for the experimental liquid. By changing the flow direction of the experimental liquid, the original full-area impact on the end face is transformed into directional conveying in the central area, significantly reducing the scouring pressure on the core end face and avoiding damage such as pitting and peeling on the end face.

[0032] like Figure 3As shown, an annular sealing ring 5 is installed inside the core docking groove 3. The annular sealing ring 5 seals the gap between the end face protective plate 2 and the experimental core body 1 to prevent experimental liquid from leaking through the gap and avoid the leakage liquid from eroding the sidewall of the core.

[0033] like Figure 4 As shown, an annular groove 6 is provided inside the core docking groove 3 and the outer wall of the guide channel cylinder 4, and an annular sealing ring 5 is disposed inside the annular groove 6. The annular groove 6 limits the annular sealing ring 5 to prevent it from falling off.

[0034] The side of the end face protective plate 2 is provided with a locking threaded hole 8, which communicates with the interior of the assembly and installation groove 7. The internal thread of the locking threaded hole 8 is connected to a limit bolt 9; the end of the limit bolt 9 is grounded on the outer wall of the flow guide tube 4. After the limit bolt 9 is screwed in, its end abuts against the surface of the flow guide tube 4, axially limiting and fixing the flow guide tube 4. By pressing and fixing the flow guide tube 4, it prevents the flow guide tube 4 from loosening or falling off under the impact of high pressure liquid, ensuring the continuous stability of the flow guiding function.

[0035] A countersunk hole 10 is provided at the opening of the locking threaded hole 8, and the head of the limiting bolt 9 is recessed inside the countersunk hole 10. The design of the countersunk hole 10 can prevent the head of the limiting bolt 9 from protruding from the surface of the end face protective plate 2, prevent the bolt head from interfering with the liquid inlet channel of the core holder, and ensure a tight fit between the holder and the end face protective plate 2 and smooth connection of the liquid channel.

[0036] A spring washer 11 is fitted over the outside of the limiting bolt 9. After the limiting bolt 9 is assembled into the locking threaded hole 8, the spring washer 11 is located inside the bolt countersunk hole 10. The spring washer 11 enhances the anti-loosening performance of the threaded connection. The elastic deformation of the spring washer 11 counteracts the vibration during the experiment, preventing the limiting bolt 9 from loosening.

[0037] A protective sleeve 12 is fitted on the end of the experimental core body 1 away from the end face protective plate 2. The protective sleeve 12 cooperates with the end face protective plate 2 to make the two ends of the core uniformly stressed, prevent the core from eccentric deformation under the action of high pressure experimental liquid, and ensure the consistency of experimental conditions.

[0038] The working principle of this embodiment is as follows:

[0039] First, snap the annular sealing ring 5 into the assembly annular groove 6 inside the core docking groove 3 of the end face protection plate 2. Then, align the end face protection plate 2 with the annular sealing ring 5 assembled through the core docking groove 3 with the end of the experimental core body 1 and slowly put it into place so that the end face protection plate 2 is tightly fitted with the end face of the core. At this time, the annular sealing ring 5 is in the gap between the end face protection plate 2 and the experimental core body 1, forming a sealing structure.

[0040] The second step involves smoothly placing the experimental core body 1, equipped with protective components, into the core holder to secure and position the core. The relative positions of the inlet channel of the core holder and the guide channel cylinder 4 on the end-face protective plate 2 are then checked to ensure unobstructed communication, laying the foundation for smooth flow of the experimental liquid. Once the experiment is started, the experimental liquid flows out of the inlet channel of the core holder at a preset pressure and flow rate, first precisely entering the guide channel cylinder 4 on the end-face protective plate 2. With the guidance of the guide channel cylinder 4, the experimental liquid is concentrated and transported to the central area of ​​the experimental core body 1, preventing direct impact on the core end face and effectively reducing the risk of erosion and scouring of the core end face.

[0041] Those skilled in the art will recognize that the embodiments described herein are intended to help the reader understand the principles of this invention, and should be understood that the scope of protection of this invention is not limited to such specific statements and embodiments. Those skilled in the art can make various other specific modifications and combinations based on these technical teachings disclosed in this invention without departing from the essence of this invention, and these modifications and combinations are still within the scope of protection of this invention.

Claims

1. A device for protecting the end face of an acid fracturing test core from erosion, characterized in that: It includes an experimental core body (1), and the ends of the experimental core body (1) are provided with protective components; The protective assembly includes an end face protective plate (2), one side of which is provided with a core docking groove (3), and the end face protective plate (2) is fitted onto the end of the experimental core body (1) through the core docking groove (3); the center of the end face protective plate (2) is provided with an assembly and installation groove (7), and a flow guide tube (4) is installed in the assembly and installation groove (7); one end of the flow guide tube (4) is connected to the liquid inlet channel of the core holder, and the other end of the flow guide tube (4) is connected to the central area of ​​the experimental core body (1).

2. The anti-erosion protection device for the end face of acid fracturing experimental cores according to claim 1, characterized in that: The core docking groove (3) is provided with an annular sealing ring (5).

3. The anti-erosion protection device for the end face of acid fracturing experimental cores according to claim 2, characterized in that: An assembly annular groove (6) is provided between the core docking groove (3) and the outer wall of the guide channel cylinder (4), and the annular sealing ring (5) is provided inside the assembly annular groove (6).

4. The anti-erosion protection device for the end face of acid fracturing experimental cores according to claim 1, characterized in that: The side of the end face protection plate (2) is provided with a locking thread hole (8). The locking thread hole (8) is connected to the interior of the assembly and installation groove (7). The internal thread of the locking thread hole (8) is connected to a limit bolt (9). The end of the limit bolt (9) is grounded on the outer wall of the guide channel cylinder (4).

5. The anti-erosion protection device for the end face of acid fracturing experimental cores according to claim 4, characterized in that: The locking threaded hole (8) has a countersunk bolt hole (10) at the opening position, and the head of the limiting bolt (9) is recessed into the countersunk bolt hole (10).

6. The anti-erosion protection device for the end face of acid fracturing experimental cores according to claim 5, characterized in that: A spring washer (11) is fitted on the outside of the limiting bolt (9). After the limiting bolt (9) is assembled into the locking threaded hole (8), the spring washer (11) is located inside the bolt countersunk hole (10).

7. The anti-erosion protection device for the end face of acid fracturing experimental cores according to any one of claims 1 to 6, characterized in that: The experimental core body (1) is fitted with a protective sleeve (12) at the end away from the end face protective plate (2).

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