A device for measuring the turning radius of repeated fracturing

Abstract

This invention relates to the field of hydraulic fracturing simulation technology in oil and gas fields, specifically to a device for measuring the turning radius of repeated fracturing. The device includes: a rock sample movably placed on the upper end of a base, with a steel pipe inserted into the middle of the rock sample; an infrared detector fixedly connected to the upper middle of a support rod, with a displacement ring mechanism fixedly connected to the lower end of the support rod, and the displacement ring mechanism installed on the upper end of the base; a computer connected to an image acquisition system and a data acquisition system via wires, the data acquisition system connected to a displacement sensor via wires, and the displacement sensor connected to the infrared detector via wires. Due to its overall structure, the device is simple, facilitates signal transmission, can acquire high-definition images, clearly define the direction and length of fracture extension, better observe the fracture extension morphology in real time, improve the efficiency of repeated fracturing, and more accurately calculate the turning radius length of repeated fracturing fractures.

Description

Technical Field

[0001] This invention relates to the field of hydraulic fracturing simulation technology for oil and gas fields, and more specifically, to a device for measuring the turning radius of repeated fracturing. Background Technology

[0002] Currently, oilfield development has entered the mid-to-late stage. To continuously develop the potential of oilfields, hydraulic fracturing is often used as a primary production enhancement measure. It is fast-acting and has significant production-enhancing effects, improving the development level of oil and gas fields. However, as the effective period of fracturing expires, the production enhancement effect diminishes. Therefore, repeated fracturing is necessary to meet development needs. Initially, research suggested that repeated fracturing simply reopened closed fractures or extended them further, merely increasing the scale of operations. Due to limitations in understanding, the effects of repeated fracturing were not ideal, resulting in poor reservoir utilization.

[0003] Until the mid-to-late 1980s, scholars both domestically and internationally conducted in-depth research from various perspectives, achieving a breakthrough in understanding that fractures after repeated fracturing might change direction compared to the original fractures. Currently, the most prominent development is in temporary plugging and reversal technology. This technology is in a popular phase, with widespread application. Research on the construction process of temporary plugging agents is relatively extensive, and a wide variety of temporary plugging materials are available, including fiber-based, resin-based, and rubber-based types. Different materials can achieve intra-layer and inter-layer temporary plugging, resolving intra-layer conflicts, fully transforming high- and low-permeability reservoirs, improving fracture conductivity, and making reservoir stimulation more uniform. By injecting temporary plugging agents into the formation, fractures can be reversed, forming complex fracture networks. This allows for the stimulation of larger areas of undeveloped land, restoring the production capacity of old wells, thereby achieving better fracturing results and sustainable development. This technology has been widely applied in oilfields.

[0004] Repeated fracturing technology for old wells is mature both domestically and internationally, and the mechanism of repeated fracturing is relatively clear. However, the understanding of the variation law and turning radius of the directional fractures generated during repeated fracturing is relatively vague, and there is relatively little research on the length of the fracture turning radius. Therefore, it is difficult to provide a strong basis for analyzing fracturing effects and summarizing experience. Therefore, in order to clarify the fracture extension morphology of repeated fracturing and improve the effect of repeated fracturing, a device for measuring the turning radius of repeated fracturing is studied. Summary of the Invention

[0005] This application provides a device for measuring the turning radius of repeated fracturing, in order to solve the problem that the existing technology has a relatively vague understanding of the variation law and turning radius of the turning crack generated during repeated fracturing, and there is relatively little research on the length of the crack turning radius, so it cannot provide a strong basis for fracturing effect analysis and experience summary.

[0006] or, To solve the above-mentioned technical problems, or at least partially solve them, this application provides an apparatus for measuring the repetitive fracturing turning radius, comprising: A base, on which a rock sample is movably placed, and a steel pipe is inserted into the middle of the rock sample. An infrared detector is fixedly connected to the upper middle part of the support rod, and a displacement ring mechanism is fixedly connected to the lower end of the support rod, and the displacement ring mechanism is installed on the upper end of the base. The computer is connected to an image acquisition system and a data acquisition system via wires. The data acquisition system is connected to a displacement sensor via wires, and the displacement sensor is connected to an infrared detector via wires.

[0007] Optionally, the bottom end of the steel pipe is provided with four liquid outlet holes in a spiral configuration.

[0008] Optionally, an artificial crack is pre-formed on the outside of the steel pipe in the rock sample.

[0009] Optionally, the displacement ring mechanism includes a rotating ring, a limiting slip ring, a circular ring rack, and a gear. The lower end of the rotating ring is fixedly connected to the limiting slip ring, and the limiting slip ring is movably inserted into the outer circular ring groove at the upper end of the base. The lower end of the limiting slip ring has a circular cavity, and a circular ring rack is fixedly connected inside the circular cavity.

[0010] Optionally, the lower end of the ring rack is meshed with a gear, and the middle part of the gear is fixedly inserted into the shaft of the drive motor, and the drive motor is fixedly connected to the upper outer side of the base.

[0011] Optionally, the upper middle part of the base has a placement groove, and the lower end of the placement groove has a rectangular opening.

[0012] Optionally, the lower part of the rock sample is placed inside the placement groove.

[0013] Optionally, the upper end of the steel pipe is provided with a pumping system.

[0014] Optionally, at least four image acquisition systems are provided, and the image acquisition systems are set on the front, back, left and right sides of the rock sample via external supports.

[0015] Optionally, the rock sample is cubic in shape and is formed by casting with cement and quartz sand.

[0016] The beneficial effects of this invention are as follows: Through its overall structure, this device can measure the length of the crack turning radius. The displacement sensor can measure the length and azimuth of the crack extension. The data acquisition system fits the crack turning azimuth and position data to simulate the crack turning trajectory. Finally, the turning radius is obtained according to the calculation method. This device is simple, has convenient signal transmission, can acquire high-definition images, clearly define the crack extension direction and length, and better observe the crack extension morphology in real time. At the same time, it improves the efficiency of repeated fracturing and can more accurately calculate the length of the crack turning radius in repeated fracturing. It can better guide the design and application of repeated fracturing and provide technical support for repeated fracturing construction parameters and fracturing effects. Attached Figure Description

[0017] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1 This is an overall structural diagram of an embodiment of the present invention.

[0019] Figure 2 This is an overall structural diagram of the base according to an embodiment of the present invention.

[0020] Figure 3 This is a cross-sectional view of the base according to an embodiment of the present invention.

[0021] Figure 4 This is a flowchart of an embodiment of the present invention.

[0022] The markings in the diagram are: 1. Base, 2. Drive motor, 3. Displacement ring mechanism, 31. Rotating ring, 32. Limiting slip ring, 33. Circular ring rack, 34. Gear, 4. Support rod, 5. Rock sample, 6. Steel pipe, 7. Infrared detector, 8. Pumping system, 9. Displacement sensor, 10. Data acquisition system, 11. Computer, 12. Image acquisition system, 13. Placement slot, 14. Rectangular opening. Detailed Implementation

[0023] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0024] It should be noted that all directional indications in the embodiments of the present invention, such as up, down, left, right, front, back, etc., are only used to explain the relative positional relationship and movement of the components in a specific posture as shown in the attached figure. If the specific posture changes, the directional indication will also change accordingly.

[0025] In this invention, unless otherwise explicitly specified and limited, the terms "connection," "fixed," etc., should be interpreted broadly. For example, "fixed" can mean a fixed connection, a detachable connection, or an integral part; it can mean a mechanical connection or an electrical connection; it can mean a direct connection or an indirect connection through an intermediate medium; it can mean 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.

[0026] Furthermore, if the embodiments of this invention involve descriptions such as "first" or "second," these descriptions are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined with "first" or "second" may explicitly or implicitly include at least one of those features. Additionally, the meaning of "and / or" throughout the text includes three parallel solutions; for example, "A and / or B" includes solution A, solution B, or a solution where both A and B are satisfied simultaneously. Furthermore, the technical solutions of the various embodiments can be combined with each other, but this must be based on the ability of those skilled in the art to implement them. When the combination of technical solutions is contradictory or impossible to implement, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection claimed by this invention.

[0027] In existing technologies, injecting temporary plugging agents into the formation can cause fractures to change direction, forming a complex fracture network. This allows for the transformation of undeveloped areas over a larger area, restoring the production capacity of old wells and achieving better fracturing results, thus enabling sustainable development. This technology has been widely used in oilfields, and the technology for repeated fracturing of old wells, both internally and externally, is mature. The mechanism of repeated fracturing is relatively clear. However, the understanding of the variation law and turning radius of the turning fractures generated during repeated fracturing is relatively vague, and there is relatively little research on the length of the fracture turning radius.

[0028] To address the aforementioned issues, this invention proposes a device for measuring the turning radius of repeated fracturing. This addresses the problem that the existing technology has a vague understanding of the variation law and turning radius of the turning cracks generated during repeated fracturing, and there is relatively little research on the length of the crack turning radius. Therefore, it cannot provide a strong basis for fracturing effect analysis and experience summarization.

[0029] like Figures 1 to 4As shown, this embodiment provides a device for measuring the repetitive fracturing turning radius, comprising: A base 1, on which a rock sample 5 is movably placed, and a steel pipe 6 is inserted into the middle of the rock sample 5. Infrared detector 7, the infrared detector 7 is fixedly connected to the upper middle part of the support rod 4, and the lower end of the support rod 4 is fixedly connected to the displacement ring mechanism 3, and the displacement ring mechanism 3 is installed on the upper end of the base 1. Computer 11 is connected to image acquisition system 12 and data acquisition system 10 via wires. Data acquisition system 10 is connected to displacement sensor 9 via wires. Displacement sensor 9 is connected to infrared detector 7 via wires.

[0030] Specifically: the infrared detector 7 is mainly used to sense the crack turning direction and then transmit the signal to the displacement sensor 9. The displacement sensor 9 can measure the length and azimuth of the crack extension. The data acquisition system 10 is connected to the displacement sensor 9, records the crack data, calculates according to the azimuth and position data of the crack turning direction according to the calculation formula, and then inputs the calculation results into the software of the computer 11 for fitting, simulating the turning trajectory of the crack, obtaining the fitted circle, and finally calculating the turning radius. The image acquisition device 12 is a CT scanner, which can acquire crack extension morphology images in real time and transmit them to the computer 11.

[0031] In this embodiment, as Figure 1 As shown, the bottom end of the steel pipe 6 has four liquid outlet holes spirally arranged.

[0032] Specifically: the outlet hole is the discharge hole after the fracturing fluid is injected into the steel pipe 6.

[0033] In this embodiment, as Figure 1 As shown: The rock sample 5 has an artificial crack pre-fabricated on the outside of the steel pipe 6.

[0034] Specifically: artificial fractures are designed to simulate the fracture distribution of an initial hydraulic fracturing.

[0035] In this embodiment, as Figure 3 As shown: The displacement ring mechanism 3 includes a rotating ring 31, a limiting slip ring 32, a circular ring rack 33, and a gear 34. The lower end of the rotating ring 31 is fixedly connected to the limiting slip ring 32, and the limiting slip ring 32 is movably inserted into the outer circular ring groove at the upper end of the base 1. The lower end of the limiting slip ring 32 has a circular cavity, and the circular ring rack 33 is fixedly connected inside the circular cavity.

[0036] Specifically: the drive motor 2 drives the gear 34 to rotate, which in turn drives the ring rack 33 to rotate, which in turn drives the rotating ring 31 to rotate, which in turn drives the support rod 4 to rotate around the outside of the rock sample 5, thereby changing the position of the infrared detector 7. This allows the infrared detector 7 to detect the rock sample 5 from different positions, thereby increasing the diversity and accuracy of data sampling.

[0037] In this embodiment, as Figure 3 As shown: the lower end of the ring rack 33 is meshed with a gear 34, and the middle part of the gear 34 is fixedly inserted into the shaft of the drive motor 2, and the drive motor 2 is fixedly connected to the upper outer side of the base 1.

[0038] Specifically: the drive motor 2 adopts an existing motor on the market, and the drive motor 2 is equipped with a dedicated controller to control the rotation speed of the drive motor 2.

[0039] In this embodiment, as Figure 1 and Figure 3 As shown: The upper middle part of the base 1 has a placement groove 13, and the lower end of the placement groove 13 has a rectangular opening 14.

[0040] Specifically: The rectangular opening 14 is the fluid outlet space. After the fracturing fluid flows out from the four outlet holes at the lower end of the steel pipe 6, it is transferred by an external transfer mechanism.

[0041] In this embodiment, as Figure 1 , Figure 2 and Figure 3 As shown: The lower part of the rock sample 5 is placed inside the placement groove 13.

[0042] Specifically: the placement groove 13 can stably place the rock sample 5.

[0043] In this embodiment, as Figure 1 and Figure 4 As shown: The upper end of the steel pipe 6 is equipped with a pumping system 8.

[0044] Specifically: the pumping system 8 uses existing equipment on the market. The pumping system 8 is used to inject fracturing fluid into the interior of the steel pipe 6, and the fracturing fluid flows out from the four outlet holes at the lower end of the steel pipe 6.

[0045] In this embodiment, as Figure 4 As shown: At least four image acquisition systems 12 are provided, and the image acquisition systems 12 are set on the front, back, left and right sides of the rock sample 5 by external brackets.

[0046] Specifically: The image acquisition system 12 adopts existing equipment systems on the market in order to acquire image data information of rock sample 5 after simulated fracturing and transmit it to computer 11 for simulation processing by software inside computer 11.

[0047] In this embodiment, as Figure 1 As shown: The rock sample 5 is cubic in shape and is formed by casting with cement and quartz sand.

[0048] Specifically: Rock sample 5 measures 300mm × 300mm × 300mm.

[0049] In field use, the pumping system is connected to rock sample 5, primarily to simulate the fracturing fluid pumping procedure, including the diversion process of the temporary plugging agent. Rock sample 5 is 300mm × 300mm × 300mm in size, constructed from cement and quartz sand. A steel pipe 6 is installed at the center of rock sample 5 to simulate a wellbore. Four spirally arranged holes at the bottom of the simulated wellbore serve as fluid outlets. An artificial fracture is prefabricated near the wellbore using cardboard to simulate the fracture distribution during initial fracturing. Rock sample 5 is connected to an infrared detector 7, which is mainly used to sense when the fracture changes direction. The signal is then transmitted to displacement sensor 9, which measures the length and azimuth of the crack extension. The data acquisition system 10 is connected to displacement sensor 9, records crack data, and calculates the crack direction according to the calculation formula based on the azimuth and position data of the crack. The calculation results are then input into the software of computer 11 for fitting, simulating the crack's turning trajectory to obtain a fitted circle, and finally calculating the turning radius. The image acquisition device 12 is a CT scanner, which can acquire crack extension morphology images in real time and transmit them to computer 11. Computer 11 is used to monitor the software for real-time display.

[0050] In this system, the crack initiation point is taken as the origin (0, 0), the direction of the maximum principal stress is the x-axis, and the direction of the minimum principal stress is the y-axis. The point (x, y) is selected as the end point of the crack extension. The calculation is performed using the formula, and then the calculation results are input into the data acquisition system 10 for software fitting. Finally, a fitted circle is obtained to determine the turning radius. The calculation formula is as follows:

[0051] In the formula, a and b are both coefficients, x is the value in the x-direction at that position, y is the value in the y-direction at that position, and r is the turning radius.

[0052] The above description is merely a specific embodiment of the present invention, enabling those skilled in the art to understand or implement the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the present invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features claimed herein.

Claims

1. A device for measuring the turning radius of repeated fracturing, characterized in that, include: A base (1) is provided, on the upper end of which a rock sample (5) is movably placed, and a steel pipe (6) is inserted into the middle of the rock sample (5). An infrared detector (7) is fixedly connected to the upper middle part of the support rod (4), and a displacement ring mechanism (3) is fixedly connected to the lower end of the support rod (4). The displacement ring mechanism (3) is installed on the upper end of the base (1). The displacement ring mechanism (3) includes a rotating ring (31), a limiting slip ring (32), a circular ring rack (33), and a gear (34). The lower end of the rotating ring (31) is fixedly connected to the limiting slip ring (32), and the limiting slip ring (32) is movably inserted into the outer circular groove of the upper end of the base (1). The lower middle part of the limiting slip ring (32) has a circular cavity, and the circular ring rack (33) is fixedly connected inside the circular cavity. Computer (11), the computer (11) is connected to image acquisition system (12) and data acquisition system (10) by wires, the data acquisition system (10) is connected to displacement sensor (9) by wires, and the displacement sensor (9) is connected to infrared detector (7) by wires.

2. The device for measuring the turning radius of repeated fracturing according to claim 1, characterized in that: The bottom end of the steel pipe (6) is provided with four liquid outlet holes in a spiral manner.

3. The device for measuring the turning radius of repeated fracturing according to claim 1, characterized in that: An artificial crack was pre-formed on the outside of the steel pipe (6) of the rock sample (5).

4. The device for measuring the turning radius of repeated fracturing according to claim 1, characterized in that: The lower end of the ring rack (33) is meshed with a gear (34), and the middle part of the gear (34) is fixedly inserted into the shaft of the drive motor (2), and the drive motor (2) is fixedly connected to the upper outer side of the base (1).

5. The device for measuring the turning radius of repeated fracturing according to claim 1, characterized in that: The upper middle part of the base (1) has a placement groove (13), and the lower end of the placement groove (13) has a rectangular opening (14) through it.

6. The device for measuring the repetitive fracturing turning radius according to claim 1, characterized in that: The lower part of the rock sample (5) is placed inside the placement groove (13).

7. The device for measuring the repetitive fracturing turning radius according to claim 1, characterized in that: The upper end of the steel pipe (6) is equipped with a pumping system (8).

8. The device for measuring the turning radius of repeated fracturing according to claim 1, characterized in that: The image acquisition system (12) is provided in at least four parts, and the image acquisition system (12) is set on the front, back, left and right sides of the rock sample (5) by external brackets.

9. The device for measuring the turning radius of repeated fracturing according to claim 1, characterized in that: The rock sample (5) is cubic in shape and is cast by cement and quartz sand.

Images