Crack orienting device for hydraulic fracturing ground stress test

Abstract

The utility model discloses a crack orienting device for a hydraulic fracturing ground stress test, which is positioned in a test section of the hydraulic fracturing ground stress test and comprises a flow guide pipe, an orienting blade and a limiting shell, the flow guide pipe is communicated with a central pipeline of the ground stress test device, and the orienting blade is communicated with the limiting shell. The guide pipe is rotatably sleeved with the directional blade, an opening is formed in the outer wall of the limiting shell, the directional blade is sleeved with the limiting shell, the directional blade extends out of the opening of the limiting shell, and therefore the limiting shell limits the rotating range of the directional blade. The device is low in manufacturing cost, and the defect that in the prior art, the measurement error of asymmetric fractures is large is effectively overcome.

Description

Technical Field

[0001] The utility model belongs to the technical field of engineering geological exploration, and particularly relates to a crack orientation device for in-situ stress testing by the hydraulic fracturing method. Background Technique

[0002] Conventional in-situ stress testing by the hydraulic fracturing method mainly consists of two parts: hydraulic fracturing testing and fracture impression testing. According to the mechanical theory of the hydraulic fracturing method, the stress magnitude and direction of the tested rock mass can be obtained respectively. At present, the conventional testing method of in-situ stress by the hydraulic fracturing method mainly realizes the independent testing of stress magnitude and direction, which consumes a long time, is cumbersome to operate, and repeated testing easily leads to borehole instability, requiring a large amount of manpower and material resources. With the development of technology, some in-situ stress testing devices for hydraulic fracturing that can simultaneously collect stress magnitude and direction have also emerged. According to their main characteristics, they can be divided into three categories: the first is to characterize the direction of the fracture formed during the fracturing test based on the wave velocity imaging method; the second is to directly show the direction of the fracture during the fracture formation process by combining the borehole televiewer imaging method; the third is to use a deflector plate to determine the fracture direction (CN116816337A). These three methods can all simultaneously collect the stress magnitude and direction of the tested rock mass, but the manufacturing costs of the first two are very high, and the degree of popularization is relatively low. In the actual application process of the third method, due to the fact that the fracture is not completely symmetrical, there will be a large fluctuation with the water flow during use, resulting in a large fracture positioning error. Therefore, it is necessary to develop a crack orientation device with a relatively low manufacturing cost and capable of obtaining accurate results under the condition of incomplete symmetry of the fracture. Content of the Utility Model

[0003] The purpose of the utility model is to provide a crack orientation device for in-situ stress testing by the hydraulic fracturing method aiming at the deficiencies of the prior art, which effectively avoids the large measurement error of non-symmetrical cracks in the prior art.

[0004] To solve the above technical problems, the utility model adopts the following technical solutions:

[0005] A crack orientation device for in-situ stress testing by the hydraulic fracturing method, the crack orientation device is located in the test section of the in-situ stress testing by the hydraulic fracturing method, and includes a diversion pipe, orientation vanes and a limiting outer shell. The diversion pipe is communicated with the central pipe of the in-situ stress testing device. The orientation vanes are rotatably sleeved on the diversion pipe. An opening is provided on the outer wall of the limiting outer shell. The limiting outer shell is sleeved on the orientation vanes and the orientation vanes extend out from the opening of the limiting outer shell, so that the limiting outer shell limits the rotation range of the orientation vanes.

[0006] Furthermore, a plurality of water outlet holes are provided on the pipe wall of the diversion pipe.

[0007] Furthermore, it includes at least two directional vanes, and each directional vane is independently arranged.

[0008] Furthermore, the opening on the limiting outer shell limits the rotation arc of the directional vane to be less than 10°.

[0009] Furthermore, the directional vane includes a central ring rotatably sleeved on the diversion pipe and blades integrally formed with the central ring. Among them, the blades are conical, and the thickness of the blades gradually decreases as they are farther away from the central ring.

[0010] Compared with the prior art, the beneficial effects of the present utility model are as follows: The directional vanes in the present utility model are independently installed, and each directional vane can rotate independently. Therefore, when the surrounding rock in the test section generates split cracks that are asymmetric cracks, the directional vanes can point to the corresponding fissures respectively under the action of water flow, effectively avoiding the disadvantage of large measurement errors for asymmetric fissures in the prior art; in addition, the present utility model has a low manufacturing cost, and the limiting outer shell can prevent the blades from rotating under the action of other external forces after the test and affecting the accuracy of orientation. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Figure 1 It is the top view of the crack orientation device for hydraulic fracturing in-situ stress testing according to the embodiment of the present utility model;

[0012] Figure 2 It is the structural schematic diagram of the diversion pipe according to the embodiment of the present utility model;

[0013] Figure 3 It is the structural schematic diagram during the test according to the embodiment of the present utility model;

[0014] Figure 4 It is the structural schematic diagram of the crack orientation device according to the embodiment of the present utility model when asymmetric fissures are generated. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0015] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the embodiments of the present utility model. Obviously, the described embodiments are only a part of the embodiments of the present utility model, rather than all the embodiments. Based on the embodiments in the present utility model, all other embodiments obtained by those of ordinary skill in the art without making creative efforts shall fall within the protection scope of the present utility model.

[0016] It should be noted that, without conflict, the embodiments in the present utility model and the features in the embodiments can be combined with each other.

[0017] Next, the present utility model will be further described in conjunction with specific embodiments, but it is not a limitation of the present utility model.

[0018] Such as Figure 1As shown in the figure, an embodiment of the present utility model discloses a crack orientation device for in-situ stress testing by hydraulic fracturing. The crack orientation device is located in the test section of the in-situ stress testing by hydraulic fracturing, and includes a diversion pipe 1, orientation vanes 2, and a limit housing 3. The diversion pipe 1 is communicated with the central pipe of the in-situ stress testing device. A plurality of water outlets 1-1 are opened on the pipe wall of the diversion pipe 1. Water flows from the central pipe of the in-situ stress testing device into the diversion pipe 1 and then flows out from the water outlets 1-1 on the diversion pipe 1. In order to facilitate the orientation of asymmetric pressure cracks, at least two orientation vanes 2 are rotatably sleeved on the diversion pipe 1. In this embodiment, two orientation vanes 2 are provided. The two orientation vanes 2 are respectively and independently sleeved on the diversion pipe 1, and in the initial installation, the installation angles of the two orientation vanes 2 are approximately parallel. Each orientation vane 2 includes a central ring rotatably sleeved on the diversion pipe 1 through a bearing and a vane 2-2 integrally formed with the central ring 2-1. In order to facilitate orientation, the vane 2-2 is set to be conical, and its thickness gradually decreases as it moves away from the central ring 2-1.

[0019] An opening is provided on the side wall of the limit housing 3. A limit housing 3 is sleeved outside the central ring 2-1 of each orientation vane 2, and the vane 2-2 thereon extends out from the opening of the limit housing 3. The limit housing 3 is provided to limit the rotation range of the orientation vane. In order to prevent the vane from rotating under the action of other external forces after the test and affecting the accuracy of orientation, the opening on the limit housing 3 limits the rotation radian of the orientation vane to be less than 10°.

[0020] The specific use process of this embodiment is as Figure 3 shown. During the in-situ stress testing process, the device is placed in the test section of the borehole 4. Water flows from the central pipe of the in-situ stress testing device into the diversion pipe 1 and then flows out from the water outlets 1-1 on the diversion pipe 1 into the test section. When the surrounding rock 5 of the test section generates splitting cracks 6, the water flow will flow along the orientation vanes 2 towards the splitting cracks 6. When the direction of the orientation vane does not point to the splitting cracks 6, the water flow will push the orientation vane 2 to point to the splitting cracks 6. When the splitting cracks 6 generated in the surrounding rock 5 of the test section are asymmetric cracks, since the orientation vanes 2 are independently arranged, the state is as Figure 4 shown. Under the action of the water flow, one of the orientation vanes has a deflection angle 7 and rotates to point to the corresponding fissure. The position before rotation is 2-2-2, and the position after rotation is 2-2-1.

[0021] The above is only a preferred embodiment of the present invention, and it does not limit the implementation manners and protection scope of the present invention accordingly. For those skilled in the art, it should be able to realize that all the equivalent replacements and obvious changes made by using the content of the present invention specification should be included in the protection scope of the present invention.

Claims

1. A crack orientation device for in-situ stress testing by hydraulic fracturing method, characterized in that, The crack orientation device is located in the test section of the in-situ stress test by hydraulic fracturing method, and includes a diversion pipe, orientation vanes and a limiting outer shell. The diversion pipe is communicated with the central pipe of the in-situ stress test device. The orientation vanes are rotatably sleeved on the diversion pipe. An opening is provided on the outer wall of the limiting outer shell. The limiting outer shell is sleeved on the orientation vanes and the orientation vanes extend out from the opening of the limiting outer shell, so that the rotation range of the orientation vanes is limited by the limiting outer shell.

2. The crack orientation device for in-situ stress measurement by hydraulic fracturing according to claim 1, characterized in that, A plurality of water outlet holes are provided on the pipe wall of the diversion pipe.

3. The crack orientation device for in-situ stress testing by hydraulic fracturing according to claim 1, characterized in that, It includes at least two orientation vanes, and each orientation vane is independently arranged.

4. The fracture orientation device for in-situ stress testing by hydraulic fracturing according to claim 1, characterized in that, The opening on the limiting outer shell limits the rotation arc of the orientation vane to be less than 10°.

5. The crack orientation device for in-situ stress measurement by hydraulic fracturing method according to claim 1, characterized in that, The orientation vane includes a central ring rotatably sleeved on the diversion pipe and blades integrally formed with the central ring. Among them, the blades are conical, and the thickness of the blades gradually decreases as they are away from the central ring.

Images