A fluid injection device for core permeability experiments

Abstract

The utility model relates to the field of oil and gas exploration and development, concretely relates to a kind of core percolation experiment fluid injection device, comprising: fluid injection pipe, head connector pipe and anti-blocking pipe head, the head connector pipe is plugged in corresponding head by jack, and the one end between head connector pipe and fluid injection pipe is detachably connected by pipe sleeve, the anti-blocking pipe head is sleeved in the other end of head connector pipe.The core innovation of the device is that the traditional static injection hole is upgraded to dynamic module with self-cleaning function.The anti-blocking pipe head serves as the first line of defense, effectively intercepting most of the debris. When local blockage occurs in the pipe opening area, the operator only needs to press the anti-blocking pipe head inward, and the blockage can be pushed out from the inside to the outside by the internally linked ejector pin and anti-blocking frame. This "one-key" unblocking mechanism shortens the cleaning time from several hours to several seconds, completely solving the problem of blockage cleaning that has plagued the field.

Description

Technical Field

[0001] This utility model relates to the field of oil and gas exploration and development, specifically to a core seepage experimental fluid injection device. Background Technology

[0002] In the geological exploration and development of oil and gas, core flow experiments are a key technical means to assess reservoir properties and study fluid flow patterns. This experiment typically involves sealing a columnar core sample in a core holder, injecting experimental fluids (such as formation water, crude oil, or chemical displacement fluid) into the core through end caps at both ends to simulate the seepage process in the underground environment, thereby obtaining core parameters such as core permeability and oil displacement efficiency.

[0003] The traditional mainstream approach involves drilling multiple fluid injection holes directly into the metal head of the core holder and connecting them to a high-pressure injection pump via external piping. However, this approach has a significant inherent drawback: during experiments, to simulate formation confining pressure, high axial and radial stresses need to be applied to the core. Under these conditions, core samples (especially loose or brittle cores) are easily compressed and rubbed against the rigid head, generating tiny rock fragments or debris. These solid particles, driven by fluid, can easily enter and clog the injection channels on the head.

[0004] Once a blockage occurs, the fluid injection pressure will fluctuate abnormally or be interrupted, leading to distorted experimental data and experimental failure. Even more challenging is the extreme difficulty in clearing blockages inside the end cap, often requiring complete disassembly of the experimental system and even the use of specialized tools, resulting in significant time and labor costs. In cases of severe blockage, the entire expensive end cap component may be rendered unusable due to the inability to clear it, greatly increasing experimental costs and time, and becoming a bottleneck restricting the improvement of experimental efficiency.

[0005] Therefore, there is an urgent need in the field for a fluid injection device that can effectively prevent blockage from a structural perspective and achieve rapid, non-disassembly-based cleaning in the event of blockage, so as to ensure the continuity, data accuracy and equipment economy of core seepage experiments. Utility Model Content

[0006] To solve the above technical problems.

[0007] This application provides a core seepage test fluid injection device, which is installed on the end cap of a core holder, including: a fluid injection pipe, an end cap connecting pipe, and an anti-blocking pipe head. The end cap connecting pipe is inserted into the corresponding end cap through a socket. One end of the end cap connecting pipe is detachably connected to the fluid injection pipe through a sleeve. The anti-blocking pipe head is sleeved on the other end of the end cap connecting pipe.

[0008] Furthermore, a ejector pin is provided inside the end cap connecting tube, and the ejector pin is fixed inside the end cap connecting tube by a cross seat.

[0009] Furthermore, the anti-blocking tube head is slidably sleeved on the outside of the end cap connecting tube, and the anti-blocking tube head and the end cap are connected by a spring.

[0010] Furthermore, the spring is sleeved on the outside of the end cap connecting pipe and installed inside the end cap through a sliding groove, with the two ends of the spring abutting against the end cap and the anti-blocking pipe head, respectively.

[0011] Furthermore, an anti-blocking frame is slidably installed inside the anti-blocking tube head, and the anti-blocking frame is provided with multiple top blocks. When the anti-blocking frame slides inward with the anti-blocking tube head, the anti-blocking frame can abut against the top pin.

[0012] Furthermore, a sealing ring is threadedly connected to the opening of the anti-clogging pipe head, and a hexagonal groove is provided on the inner side of the sealing ring.

[0013] The core seepage test fluid injection device provided by this utility model, through its innovative structural design, brings the following series of significant beneficial effects: 1. The core innovation of this device lies in upgrading the traditional static injection port to a dynamic module with self-cleaning capabilities. The anti-clogging head acts as the first line of defense, effectively intercepting most rock debris. When localized blockage occurs in the pipe opening area, the operator simply needs to press the anti-clogging head inwards, and the internally linked ejector pin and anti-clogging frame will push the blockage outwards. This "one-click" unclogging mechanism reduces the cleaning time from several hours using traditional methods to just seconds, completely solving the problem of blockage removal that has plagued this field. 2. The device adopts segmented, detachable connections (such as pipe sleeve connections and threaded sealing rings), making the installation, maintenance, and replacement of each component exceptionally convenient. For example, when the anti-clogging frame or ejector pin wears down due to long-term use, it can be easily replaced individually without replacing the entire end cap or injection device, significantly reducing the long-term maintenance costs of the equipment; 3. The built-in spring mechanism ensures that the anti-clogging tube head automatically returns to its original working position after the unclogging operation is completed, without the need for manual intervention. This design ensures that the unclogging operation does not interrupt the experimental process, making it particularly suitable for displacement experiments that require long-term continuous operation, greatly improving the continuity of the experiment and the integrity of the data; 4. The device features a compact overall structure. Its end cap connecting pipe can directly replace the injection port plug on traditional end caps, allowing for seamless integration into various existing standard core holders without requiring any modifications to the main equipment. This not only reduces upgrade costs for users but also enables its rapid adoption and widespread use in laboratories. 5. By effectively avoiding pressure fluctuations and fluid interruptions caused by flow channel blockage, this device ensures the stability of experimental conditions (such as injection pressure and flow rate), thereby directly improving the accuracy and reliability of the collected seepage data. At the same time, it reduces mechanical cleaning damage to the end cap body, effectively extending the service life of core components. Attached Figure Description

[0014] Figure 1 This is a schematic diagram of the three-dimensional structure of the present invention. Figure 1 .

[0015] Figure 2 This is a half-sectional view of the present invention after installation.

[0016] Figure 3 This is a schematic diagram of the three-dimensional structure of the present invention. Figure 2 .

[0017] Figure 4 for Figure 2 Enlarged view of point A in the image.

[0018] Figure 5 for Figure 3 Enlarged view of point B in the middle.

[0019] The numbers in the diagram are: 1-end cap; 11-insertion hole; 12-sliding groove; 2-fluid injection pipe; 3-end cap connecting pipe; 31-ejector pin; 32-cross seat; 4-anti-blocking pipe head; 41-anti-blocking bracket; 411-top block; 42-sealing ring; 421-hexagonal groove; 5-pipe sleeve; 6-spring. Detailed Implementation

[0020] The following description is intended to disclose the present invention so that those skilled in the art can implement it. The preferred embodiments described below are merely examples, and other obvious variations will occur to those skilled in the art.

[0021] like Figures 1 to 5 As shown; the specific installation and working process of this utility model is as follows: Installation process: First, correctly load the core sample into the core holder. Then, insert the end cap connecting pipe 3 from the outside of the end cap 1 into its preset insertion hole 11, ensuring proper insertion. Next, connect and lock the fluid injection pipe 2 to the outer end of the end cap connecting pipe 3 through a standard quick-connect sleeve 5, forming a reliable fluid channel. At this point, the anti-clogging head 4 has already been fitted onto the end of the end cap connecting pipe 3 that extends into the holder before leaving the factory or during pre-installation, and its internal anti-clogging bracket 41 is already installed in place. The spring 6 is pre-compressed between the anti-clogging head 4 and the inner wall of the end cap 1, providing continuous restoring force. Finally, use a hex wrench inserted into the hexagonal groove 421 inside the sealing ring 42 to screw it into the threaded end of the anti-clogging head 4, completing the assembly of the entire device.

[0022] Work and clearing process: At the start of the experiment, the high-pressure fluid flows sequentially through the fluid injection pipe 2 and the end cap connecting pipe 3, and finally flows out evenly from the opening of the anti-blocking pipe head 4, acting on the end face of the core.

[0023] Normal injection state: Under the preload of spring 6, the anti-blocking tube head 4 maintains its initial position, keeping a small gap or slight contact with the core end face, and the fluid is injected smoothly.

[0024] Unblocking Operation Status: If an abnormal increase in injection pressure is detected, indicating pipe blockage, the operator can gently push the anti-blocking head 4 inwards towards the end cap 1 using their hand or a tool. The anti-blocking head 4 slides inwards against the force of the spring 6, causing the internal anti-blocking frame 41 to move inwards as well. When the anti-blocking frame 41 contacts the tip of the ejector pin 31 fixed on the cross seat 32, the blocking action of the ejector pin 31 will force the anti-blocking frame 41 to slide outwards relative to the anti-blocking head 4. Since the anti-blocking frame 41 is equipped with multiple ejector blocks 411, this outward sliding action will effectively push out the rock debris and blockage accumulated near the pipe opening, thus clearing the blockage.

[0025] Automatic reset: After the unblocking action is completed, release the anti-blocking tube head 4. Under the restoring force of the spring 6, the anti-blocking tube head 4 automatically slides outward and returns to the initial working position. The entire unblocking process is completed instantly, and the experiment can continue.

[0026] Maintenance process: For deep cleaning or component replacement, use a hex wrench to unscrew the sealing ring 42 at the pipe opening. After unscrewing, the anti-clogging bracket 41 can be removed from the anti-clogging pipe head 4 for cleaning or direct replacement. For maintenance of the ejector pin 31, it can be inspected or replaced by disassembling the fluid injection pipe 2 and the sleeve 5, and then accessing the end of the end cap connecting pipe 3 from the other end. This modular design makes routine maintenance simple and efficient.

[0027] The foregoing has shown and described the basic principles, main features, and advantages of this utility model. Those skilled in the art should understand that this utility model is not limited to the above embodiments. The embodiments and descriptions in the specification are merely principles of this utility model. Various changes and modifications can be made to this utility model without departing from its spirit and scope, and all such changes and modifications fall within the scope of the claimed utility model. The scope of protection of this utility model is defined by the appended claims and their equivalents.

Claims

1. A core seepage experiment fluid injection device, installed on the end cap (1) of a core holder, characterized in that, include: The fluid injection pipe (2), the end cap connecting pipe (3), and the anti-blocking pipe head (4) are provided. The end cap connecting pipe (3) is inserted into the corresponding end cap (1) through the insertion hole (11). One end of the end cap connecting pipe (3) is detachably connected to the fluid injection pipe (2) through the pipe sleeve (5). The anti-blocking pipe head (4) is sleeved on the other end of the end cap connecting pipe (3).

2. The core seepage experimental fluid injection device according to claim 1, characterized in that, The end cap connecting tube (3) is provided with a ejector pin (31), which is fixed inside the end cap connecting tube (3) by a cross seat (32).

3. The core seepage experimental fluid injection device according to claim 1, characterized in that, The anti-blocking pipe head (4) is slidably sleeved on the outside of the end cap connecting pipe (3), and the anti-blocking pipe head (4) and the end cap (1) are connected by a spring (6).

4. The core seepage test fluid injection device according to claim 3, characterized in that, The spring (6) is sleeved on the outside of the end cap connecting pipe (3) and installed in the end cap (1) through the sliding groove (12). The two ends of the spring (6) abut against the end cap (1) and the anti-blocking pipe head (4) respectively.

5. The core seepage experimental fluid injection device according to claim 4, characterized in that, An anti-blocking frame (41) is slidably installed inside the anti-blocking head (4). The anti-blocking frame (41) is provided with multiple top blocks (411). When the anti-blocking frame (41) slides inward with the anti-blocking head (4), the anti-blocking frame (41) can abut against the top pin (31).

6. The core seepage experimental fluid injection device according to claim 5, characterized in that, The anti-blocking pipe head (4) has a sealing ring (42) threaded at the pipe opening, and a hexagonal groove (421) is provided on the inner side of the sealing ring (42).

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