Downward drilling in-hole flow field structure and stress observation system

Abstract

An in-hole flow field structure and stress observation system for a downward drill hole comprises an integrated drill rod, a drill bit is arranged at one end of the integrated drill rod, and a visual image acquisition system and a particle image acquisition system are arranged between the drill bit and the integrated drill rod; a plurality of annular pressure sensors are arranged in the integrated drill rod in the length direction of the integrated drill rod; a wire is arranged in the integrated drill rod in a penetrating mode in the length direction of the integrated drill rod, and the wire is electrically connected with the visual image obtaining system, the particle image obtaining system and the multiple annular pressure sensors. According to the invention, the visual image acquisition system and the particle image acquisition system are integrally arranged on the drill rod and the drill bit, so that the conditions of gas, water and slag flow fields in the drill hole can be observed from a plurality of positions in the middle of the drill hole and the bottom of the drill hole; and the stress collection in the high-pressure gas-liquid two-phase jet flow process of the drill hole can be completed.

Description

Technical Field

[0001] This invention relates to the field of gas extraction equipment technology, and in particular to a flow field structure and stress observation system for a downhole borehole. Background Technology

[0002] Compared with conventional water jet technology, high-pressure gas-liquid two-phase jet drilling has advantages such as water saving, high impact frequency, large erosion volume, and weak "water cushion effect." However, when jet drilling is a downward drilling process, the flow behavior of the three-phase mixture of gas, water, and slag in the borehole under the action of high-pressure gas-liquid two-phase jet exhibits two significant characteristics: on the one hand, slag particles flow in the borehole with the flow medium under the carrying effect of the gas-liquid fluid; on the other hand, when the gas-liquid flow velocity is lower than the critical flow velocity of the slag particles, the slag particles will be deposited at the bottom of the borehole under the action of gravity. In particular, the deposition phenomenon not only reduces the effective flow cross-sectional area in the borehole, but also causes borehole blockage in severe cases, further affecting the stability and efficiency of the flow. This makes the flow pattern in the borehole more complex and variable, with frequent transformations of flow patterns such as slug flow, bubble flow, slug flow, and annular flow, resulting in reduced stability of water and slag transportation and affecting the efficiency of water and slag transportation in the borehole. The dynamic characteristics of the three-phase mixed flow of gas, water, and slag are closely related to the flow pattern. The flow pattern determines the distribution and interaction of the three phases, directly affecting the dynamic characteristics of the three-phase flow. Changes in the dynamic characteristics also have a reciprocal effect on the flow pattern, further influencing the formation and transformation of the flow pattern by changing the distribution and motion state of the three phases.

[0003] Therefore, a flow field structure and stress observation system for high-pressure gas-liquid two-phase jet drilling is needed. By observing the changes in the flow field and the evolution of the impact force of bubble breakage, the flow field transformation characteristics and dynamic evolution characteristics of the gas-water-slag three-phase mixed flow in the borehole under high-pressure gas-liquid two-phase jet conditions can be revealed, providing theoretical support for optimizing the permeability enhancement process parameters of high-pressure gas-liquid two-phase jet in low-permeability coal seams in underground coal mines. Summary of the Invention

[0004] The present invention aims to at least partially solve one of the technical problems in the related art.

[0005] To achieve the above objectives, this invention proposes a flow field structure and stress observation system for a downhole borehole, comprising an integrated drill rod, a drill bit at one end of the integrated drill rod, a visual image acquisition system and a particle image acquisition system between the drill bit and the integrated drill rod; and multiple annular pressure sensors arranged inside the integrated drill rod along its length. A wire is embedded inside the integrated drill rod along its length. The wire is electrically connected to the visible image acquisition system, the particle image acquisition system, and the multiple annular pressure sensors.

[0006] This invention integrates a visual image acquisition system and a particle image acquisition system into the drill rod and drill bit, enabling observation of the gas, water, and slag flow fields in the borehole from multiple locations in the middle of the borehole and at the bottom of the borehole. Furthermore, by setting up multiple annular pressure sensors, stress acquisition can be completed during the high-pressure gas-liquid two-phase jet process in the borehole.

[0007] Optionally, the visible image acquisition system includes a plurality of first built-in cameras and a plurality of second built-in cameras; Multiple first built-in cameras are disposed on the outer side wall of the integrated drill rod along the length direction of the integrated drill rod, and the multiple first built-in cameras are equally spaced apart; the cameras of the integrated drill rod cameras are used to acquire image information outside the side wall of the integrated drill rod; Multiple second built-in cameras are disposed at the end of the drill bit facing the integrated drill rod, and the multiple second built-in cameras are arranged at equal angular intervals along the rotation axis of the drill bit; the second built-in cameras are used to acquire image information from the bottom of the borehole.

[0008] Furthermore, the number of the plurality of first built-in cameras and the plurality of annular pressure sensors are set to be the same, and the arrangement positions of the plurality of first built-in cameras and the arrangement positions of the plurality of annular pressure sensors are arranged adjacent to each other in a one-to-one correspondence.

[0009] Furthermore, the positions of the plurality of first built-in cameras and the plurality of annular pressure sensors are all set at a distance of 0.5m, 1.5m and 2.5m from the drill bit.

[0010] Furthermore, the particle image acquisition system includes a particle image receiver and multiple particle image generators; The particle image receiver is located inside the integrated drill rod at the end furthest from the drill bit. The particle image generator is disposed on the end face of the drill bit facing the integrated drill rod.

[0011] Furthermore, the number of the multiple particle image generators is the same as the number of the multiple second built-in cameras, and the multiple particle image generators are arranged adjacent to each other in a one-to-one correspondence with the arrangement positions of the multiple second built-in cameras.

[0012] Furthermore, the annular pressure sensor is configured as an integrated thin-film distributed pressure sensor with parameters of ±0.1% FS and 20Hz.

[0013] Furthermore, the drill bit is configured as a twist drill bit.

[0014] Furthermore, the drill bit and the integrated drill rod are detachably threadedly connected; and the end of the integrated drill rod away from the drill bit is provided with a threaded structure for connecting to a regular drill rod.

[0015] Furthermore, the end of the wire away from the drill bit extends out of the integrated drill rod, and the wire is electrically connected to a computer.

[0016] Additional aspects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0017] The above and / or additional aspects and advantages of the present invention will become apparent and readily understood from the following description of the embodiments taken in conjunction with the accompanying drawings, wherein: Figure 1 This is a schematic diagram of the overall structure of the flow field structure and stress observation system inside a downhole borehole according to the present invention.

[0018] Explanation of reference numerals in the attached figures: 1. Wire; 2. Particle image receiver; 3. First built-in camera; 4. Ring pressure sensor; 5. Drill rod; 6. Second built-in camera; 7. Particle image generator; 8. Drill bit. Detailed Implementation

[0019] Embodiments of the present invention are described in detail below, examples of which are illustrated in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain the present invention, and should not be construed as limiting the present invention.

[0020] This invention proposes a flow field structure and stress observation system for downhole drilling, as described below. Figure 1 Please provide a detailed explanation.

[0021] A flow field structure and stress observation system for a downhole borehole includes an integrated drill rod 5, with a drill bit 8 at one end of the integrated drill rod 5. A visual image acquisition system and a particle image acquisition system are arranged between the drill bit 8 and the integrated drill rod 5. Multiple annular pressure sensors 4 are arranged inside the integrated drill rod 5 along its length. An internal wire 1 is embedded in the integrated drill rod 5 along its length. The wire 1 is electrically connected to the visual image acquisition system, the particle image acquisition system, and the multiple annular pressure sensors 4.

[0022] This invention integrates a visual image acquisition system and a particle image acquisition system on the drill rod 5 and the drill bit 8, which can observe the flow field of gas, water and slag in the borehole from multiple positions in the middle of the borehole and the bottom of the borehole. Furthermore, by setting multiple annular pressure sensors 4, stress acquisition can be completed during the high-pressure gas-liquid two-phase jet process in the borehole.

[0023] Specifically, when high-pressure gas-liquid two-phase jet is carried out in the borehole, the staff can observe the gas, water and slag flow field in the borehole through the visual image acquisition system. With the setting of multiple annular pressure sensors 4, the changes in bubble rupture morphology can be observed, and the impact force generated by bubble rupture at different locations can be collected in real time.

[0024] In some embodiments, the visible image acquisition system includes a plurality of first built-in cameras and a plurality of second built-in cameras; Multiple first built-in cameras are disposed on the outer side wall of the integrated drill rod 5 along the length direction of the integrated drill rod 5, and the multiple first built-in cameras are equally spaced apart; the cameras of the integrated drill rod 5 cameras are used to acquire image information outside the side wall of the integrated drill rod 5; Multiple second built-in cameras are disposed at one end of the drill bit 8 facing the integrated drill rod 5, and the multiple second built-in cameras are arranged at equal angular intervals along the rotation axis of the drill bit 8; the second built-in camera 6 is used to acquire image information from the bottom of the borehole.

[0025] Specifically, the number of the plurality of first built-in cameras 3 and the plurality of annular pressure sensors 4 are the same, and the arrangement positions of the plurality of first built-in cameras 3 and the arrangement positions of the plurality of annular pressure sensors 4 are arranged adjacent to each other in a one-to-one correspondence. In one embodiment, the number of both the first built-in cameras 3 and the plurality of annular pressure sensors 4 is set to 3, and the arrangement positions of the first built-in cameras 3 and the plurality of annular pressure sensors 4 are set to: 80.5m, 1.5m, and 2.5m away from the drill bit.

[0026] In some embodiments, the particle image acquisition system includes a particle image receiver 2 and a plurality of particle image generators 7; The particle image receiver 2 is located inside the integrated drill rod 5 at the end away from the drill bit 8; and the particle image receiver 2 is configured as a PIV particle image acquisition device. The particle image generator 7 is disposed on the end face of the drill bit 8 facing the integrated drill rod 5.

[0027] It can realize continuous observation of the flow field inside the hole from the bottom of the hole, accurately capture the collection and dispersion characteristics of bubbles inside the hole, and the flow characteristics of water and slag. In some embodiments, the number of the plurality of particle image generators 7 is the same as the number of the plurality of second built-in cameras 6, and the plurality of particle image generators 7 are arranged adjacent to each other in a one-to-one correspondence with the arrangement positions of the plurality of second built-in cameras 6.

[0028] In some embodiments, the annular pressure sensor 4 is configured as an integrated thin-film distributed pressure sensor with parameters of ±0.1% FS and 20Hz.

[0029] In some embodiments, the drill bit 8 is configured as a twist drill bit 8. The drill bit 8 has a diameter of 113~120mm and is connected to the drill rod 5 via a pre-set thread. The twist drill bit 8's shape allows for better drainage and slag removal. In some embodiments, the drill bit 8 and the integrated drill rod 5 are detachably threadedly connected; and the integrated drill rod 5 has a threaded structure at the end away from the drill bit 8 for connecting to a regular drill rod 5.

[0030] In some embodiments, the end of the wire 1 away from the drill bit 8 extends out of the integrated drill rod 5, and the wire 1 is electrically connected to a computer. This enables continuous monitoring of the annular impact force of the high-pressure gas-liquid two-phase jet.

[0031] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this invention and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0032] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this invention, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0033] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection, an electrical connection, or a connection that allows communication between them; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise explicitly limited. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0034] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "over," and "on top" of the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0035] In this invention, the terms "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., refer to a specific feature, structure, material, or characteristic described in connection with that embodiment or example, which is included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0036] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention.

Claims

1. A flow field structure and stress observation system for a downhole borehole, characterized in that, The system includes an integrated drill rod, one end of which is provided with a drill bit. A visual image acquisition system and a particle image acquisition system are provided between the drill bit and the integrated drill rod. Multiple annular pressure sensors are provided inside the integrated drill rod along its length. A wire is embedded inside the integrated drill rod along its length. The wire is electrically connected to the visible image acquisition system, the particle image acquisition system, and the multiple annular pressure sensors.

2. The flow field structure and stress observation system inside a downhole borehole as described in claim 1, characterized in that, The visible image acquisition system includes multiple first built-in cameras and multiple second built-in cameras; Multiple first built-in cameras are disposed on the outer side wall of the integrated drill rod along the length direction of the integrated drill rod, and the multiple first built-in cameras are equally spaced apart; the cameras of the integrated drill rod cameras are used to acquire image information outside the side wall of the integrated drill rod; Multiple second built-in cameras are disposed at the end of the drill bit facing the integrated drill rod, and the multiple second built-in cameras are arranged at equal angular intervals along the rotation axis of the drill bit; the second built-in cameras are used to acquire image information from the bottom of the borehole.

3. The flow field structure and stress observation system inside a downhole borehole as described in claim 2, characterized in that, The number of the plurality of first built-in cameras and the plurality of annular pressure sensors are set to be the same, and the arrangement positions of the plurality of first built-in cameras and the arrangement positions of the plurality of annular pressure sensors are arranged adjacent to each other in a one-to-one correspondence.

4. The flow field structure and stress observation system inside a downhole borehole as described in claim 3, characterized in that, The positions of the multiple first built-in cameras and the multiple annular pressure sensors are all set at a distance of 0.5m, 1.5m and 2.5m from the drill bit.

5. The flow field structure and stress observation system inside a downhole borehole as described in claim 2, characterized in that, The particle image acquisition system includes a particle image receiver and multiple particle image generators; The particle image receiver is located inside the integrated drill rod at the end furthest from the drill bit. The particle image generator is disposed on the end face of the drill bit facing the integrated drill rod.

6. The flow field structure and stress observation system inside a downhole borehole as described in claim 5, characterized in that, The number of the multiple particle image generators is the same as the number of the multiple second built-in cameras, and the multiple particle image generators are arranged adjacent to each other in a one-to-one correspondence with the multiple second built-in cameras.

7. The flow field structure and stress observation system inside a downhole borehole as described in claim 1, characterized in that, The annular pressure sensor is configured as an integrated thin-film distributed pressure sensor with parameters of ±0.1% FS and 20Hz.

8. The flow field structure and stress observation system inside a downhole borehole as described in claim 1, characterized in that, The drill bit is configured as a twist drill bit.

9. The flow field structure and stress observation system inside a downhole borehole as described in claim 1, characterized in that, The drill bit and the integrated drill rod are detachably threadedly connected; and the integrated drill rod has a threaded structure at the end away from the drill bit for connecting to a regular drill rod.

10. The flow field structure and stress observation system inside a downhole borehole as described in claim 1, characterized in that, The end of the conductor away from the drill bit extends out of the integrated drill rod, and the conductor is electrically connected to a computer.

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