Horizontal well staged fracturing simulation test device and test method

Abstract

The present application relates to oil and gas well completion technical field, especially to a kind of horizontal well segmented fracturing simulation test device, including casing, fracturing pipe column, packer, valve and pressure sensor, the first end of casing is open, the second end of casing is closed;Fracturing pipe column is arranged in casing, including injection pipe and sequentially connected by injection pipe from the second end of casing to the first end of casing direction including setting ball seat, anchor, multiple switch sliding sleeves and packer hanger, annulus is formed between injection pipe and casing;Packer is sleeved on injection pipe and divides annulus into multiple sections, one switch sliding sleeve is arranged in each closed annular section;Valve and pressure sensor are arranged on the lateral wall of casing and correspond to switch sliding sleeve one by one;The above-mentioned horizontal well segmented fracturing simulation test device can simulate horizontal well segmented fracturing technology, and the test method using the above-mentioned horizontal well segmented fracturing simulation test device is simple in operation and low in investment cost.

Description

Technical Field

[0001] This invention relates to the field of oil and gas well completion technology, and in particular to a horizontal well segmented fracturing simulation test device and test method. Background Technology

[0002] In recent years, horizontal well staged fracturing technology has become increasingly widely used as the best method for enhancing the production of low-pressure, low-porosity, and low-permeability oil and gas reservoirs. It offers advantages such as maximum contact area with the reservoir, good fracturing effect, improved permeability conditions, increased productivity of horizontal wells, low pollution, the ability to operate multiple stages simultaneously, and rapid flowback after completion. However, its application has placed higher demands on the maturity of the technology and the stability of the tools used. Therefore, comprehensive performance testing of all tools used in horizontal well staged fracturing technology is necessary before running them into the well.

[0003] Existing testing methods can only test one tool in a horizontal well fracturing string individually. Testing multiple tools is a complex process that requires various testing equipment and lacks a comprehensive testing method for the overall performance of the tools. Summary of the Invention

[0004] One of the objectives of this invention is to provide a horizontal well segmented fracturing simulation test device, which can conduct a series of tests and experiments on multiple tools in the horizontal well segmented fracturing process, and comprehensively verify the comprehensive indicators and performance of the horizontal well segmented fracturing string.

[0005] To achieve this objective, the present invention adopts the following technical solution:

[0006] A horizontal well segmented fracturing simulation test device includes a casing, a casing anchor, a fracturing string, a packer, valves, and pressure sensors. The casing has an open first end and a closed second end. The casing anchor is configured to secure the casing. The fracturing string is disposed inside the casing and includes an injection pipe and a setting ball, an anchor, multiple switch sleeves, and a packer hanger, sequentially connected from the injection pipe towards the first end of the casing, forming an annulus between the injection pipe and the casing. The packer is fitted onto the injection pipe and divides the annulus into multiple segments, with one switch sleeve disposed within each closed annulus segment. The valves and pressure sensors are disposed on the casing sidewall and correspond one-to-one with the switch sleeves.

[0007] Optionally, the number of the sleeve fixing anchors shall not be less than two.

[0008] Optionally, the sleeve fixing anchor is formed by screwing together two semi-annular retaining rings.

[0009] Optionally, a check valve is connected to the end of the injection tube.

[0010] Optionally, the inlet end of the flow valve is connected to a guide shoe.

[0011] Optionally, there are 2-4 switch sleeves, wherein the switch sleeve closest to the end of the injection tube is a differential pressure sleeve, and the other switch sleeves are ball-throwing sleeves.

[0012] Optionally, the packer is a self-expanding packer.

[0013] Another objective of this invention is to provide a method for simulating horizontal well fracturing in stages, using the horizontal well fracturing simulation test apparatus described in the claims, specifically comprising the following steps:

[0014] S1. Fix the casing to the ground using the casing fixing anchor, and insert the fracturing string into the casing;

[0015] S2. The packer seals the annular space;

[0016] S2. Connect the fracturing string to the external pressurization device, close all the valves, insert the setting ball, and start pressurization. After the setting ball enters the setting ball seat, the pressure will rise to the set pressure value and stabilize. The anchor and the packer hanger will be set. Continue pressurization until the packer hanger is released. Observe the pressurization pressure at this time.

[0017] S3. Open the valve closest to the end of the injection tube, close the other valves, pressurize the injection tube to the set value, observe whether liquid flows out from the opened valve, close the valve, continue to pressurize to the set pressure value and stabilize the pressure, observe the value displayed by the pressure sensor connected to the valve;

[0018] S4. Starting from the side closest to the end of the injection tube and moving away from the end of the injection tube, sequentially open the valves and switch sleeves of the other annular sections, observe whether liquid flows out from the opened valves, then close the valves and observe the value displayed by the pressure sensor connected to the valves.

[0019] Optionally, the switch sleeve closest to the end of the injection tube is a differential pressure sleeve, which is opened by applying pressure into the injection tube.

[0020] Optionally, except for one switch sleeve near the end of the injection tube which is a differential pressure sleeve, the other switch sleeves are ball-throwing sleeves, which are opened by throwing a ball into the injection tube and applying pressure.

[0021] The beneficial effects of this invention are as follows: The horizontal well segmented fracturing simulation test device proposed in this invention can simulate horizontal well segmented fracturing technology. It uses casing to simulate the open hole diameter section or casing section, and uses valves installed on the casing to simulate the fracturing of the section. This invention also proposes a test method using the above-mentioned horizontal well segmented fracturing simulation test device. By observing the fluid flow at the valve, the opening status of the switch sleeve on the fracturing string can be verified. By observing the changes in the values ​​displayed by the pressure sensor, the sealing performance of the packer can be verified. By observing the setting status of the anchor and packer hanger and the pressure applied, the setting and release performance of the fracturing string can be verified. Except for opening the valves sequentially, the other steps of the above test method are the same as the operation steps of horizontal well segmented fracturing operations in actual construction. The method is simple, easy to operate, and has low test costs. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of the structure of the horizontal well segmented fracturing simulation test device proposed in the embodiments of the present invention.

[0023] In the diagram: 1. Sleeve; 2. Sleeve fixing anchor; 3. Packer hanger; 4. Packer I; 5. Switch sleeve I; 6. Valve I; 7. Pressure sensor I; 8. Packer II; 9. Switch sleeve II; 10. Valve II; 11. Pressure sensor II; 12. Packer III; 13. Switch sleeve III; 14. Valve III; 15. Pressure sensor III; 16. Anchor; 17. Setting ball seat; 18. Check valve; 19. Guide shoe; 20. Pressure hose; 21. Insertion head. Detailed Implementation

[0024] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and not intended to limit it. Furthermore, it should be noted that, for ease of description, the accompanying drawings show only the parts relevant to the present invention, and not all of the structures.

[0025] In the description of this invention, unless otherwise explicitly specified and limited, the terms "connected," "linked," and "fixed" 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 or an electrical connection; 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. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0026] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0027] In the description of this embodiment, the terms "upper," "lower," "left," and "right," etc., refer to the orientation or positional relationship shown in the accompanying drawings. They are used only for ease of description and simplification of operation, and do not 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 the present invention. In addition, the terms "first" and "second" are used only for distinction in description and have no special meaning.

[0028] The challenges of horizontal well staged fracturing technology lie in the selection of staged fracturing processes and downhole sealing tools. Currently, the main technologies for horizontal well staged fracturing, both domestically and internationally, are chemical isolation, mechanical isolation staged fracturing, flow-limiting fracturing, and hydraulic jet fracturing. This embodiment proposes a horizontal well staged fracturing simulation test device, primarily used to test various tools in mechanical isolation staged fracturing. Utilizing simple surface testing equipment, it can conduct a series of tests and experiments on the reliability of the hangers and hydraulic release mechanisms in the horizontal well staged fracturing string before well entry, the sealing performance of the packer, and the opening and closing stability of the switch sleeve. This comprehensively verifies the overall indicators and performance of the horizontal well staged fracturing string, providing targeted guidance for further optimization and improvement of the tools.

[0029] refer to Figure 1 As shown, the horizontal well segmented fracturing simulation test device in this embodiment includes a casing 1, a casing anchor 2, valves, pressure sensors, fracturing tubing string, and a packer. The casing 1 is used to simulate an open hole section or a casing section, with its first end open and its second end closed. The casing anchor 2 is fitted onto the casing 1 to fix the casing 1. The fracturing tubing string is set inside the casing 1 and includes an injection pipe and a setting ball seat 17, an anchor 16, a switch sleeve, and a packer hanger 3, which are connected sequentially from the second end near the casing 1 to the first end of the casing 1 through the injection pipe. An annulus is formed between the injection pipe and the casing 1. The packer is fitted onto the injection pipe and divides the annulus into multiple segments. A switch sleeve is set in each closed annulus segment (that is, no switch sleeve is set in the annulus formed at the first open end of the casing 1). The valve and pressure sensor are set on the side wall of the casing 1 and correspond one-to-one with the switch sleeves.

[0030] The setting ball seat 17, anchor 16, packer hanger 3, switch sleeve, and packer are all existing tools used for staged fracturing in horizontal wells. Using this horizontal well staged fracturing simulation test device, the overall performance of the aforementioned tools and the fracturing string composed of them can be comprehensively simulated on the surface for testing. The method is simple, easy to operate, and has low testing costs. During the test, the injection tubing is connected to an external pressure testing device, and the operation is carried out according to the process of staged fracturing in a production horizontal well. The setting ball is inserted into the injection tubing to test the setting and release performance. Then, the switch sleeve is opened in stages, and the valves are opened to simulate the fracturing positions in the well section. The pressure sensor readings and whether there is fluid outflow at the valves are observed to verify the performance of each part of the fracturing string.

[0031] The injection pipe simulates different objects depending on the actual mining target; it can simulate oil pipes used in oil extraction or gas pipes used in natural gas extraction.

[0032] Specifically, there are no fewer than two sleeve fixing anchors 2, which are spaced apart and fitted onto the sleeve 1 to ensure the stability of the sleeve 1. For example, the sleeve fixing anchor 2 is formed by screwing together semi-circular retaining rings at both ends, and the inner diameter of the retaining rings is the same as the outer diameter of the sleeve 1.

[0033] The end of the injection tube (the first end furthest from the casing 1) is also connected to a check valve 18 and a guide shoe 19. The check valve 18 is a tool to prevent blowout and overflow during the lowering of the tubing string. Specifically, it is a float-type check valve. The guide shoe 19 is connected to the inlet end of the check valve 18 and is used to guide the injection tube smoothly into the casing 1.

[0034] Depending on the staged fracturing operation of horizontal wells, 2-4 switching sleeves are typically configured, with the one closest to the injection pipe being the differential pressure sleeve and the others being ball-drop sleeves. In this embodiment, three switching sleeves are configured. In other embodiments, the switching sleeves can be opened and closed via wireline operation.

[0035] The packer is a self-expanding packer that automatically expands when exposed to water, and can seal the annulus.

[0036] This embodiment also includes a horizontal well segmented fracturing simulation test method, which is carried out using the above-mentioned horizontal well segmented fracturing simulation test device.

[0037] refer to Figure 1As shown, taking an example with three switch sleeves, the switch sleeves in this horizontal well segmented fracturing simulation test device include switch sleeve 5, switch sleeve 9, and switch sleeve 13 arranged sequentially. Switch sleeve 5 and switch sleeve 9 are ball-throwing sleeves, and switch sleeve 13 is a differential pressure sleeve. Valves include valve 6, valve 10, and valve 14 arranged sequentially. Pressure sensors include pressure sensor 7, pressure sensor 11, and pressure sensor 15 arranged sequentially. Packers include packer 4, packer 8, and packer 12 arranged sequentially. The test method specifically includes the following steps:

[0038] S1. Fix the prefabricated casing 1 to the ground through the casing fixing anchor 2. Connect the fracturing string in the following order: guide shoe 19, float valve 18, set ball seat 17, anchor 16, switch sliding sleeve 3 13, packer 3 12, switch sliding sleeve 2 9, packer 2 8, switch sliding sleeve 1 5, packer 1 4, and packer hanger 3, and put it into the casing 1.

[0039] S2. A certain amount of liquid is injected into the annulus, causing the packer to expand and seal the annulus.

[0040] S3. Connect the fracturing string and the external pressure device using the pressure hose 20 with the insertion head 21. Close valve 1 6, valve 2 10 and valve 3 14. Insert the setting ball and start pressurizing into the injection tube. After the setting ball enters the setting ball seat 17, the pressure rises to the set pressure value. Stabilize the pressure for 3-5 minutes. The anchor 16 and the packer hanger 3 are set. Continue pressurizing until the packer hanger 3 is released. Observe the pressure at this time. The fracturing string setting and release performance test is completed.

[0041] S4. Open valve 314 and close other valves. Pressurize the injection pipe to the set value. If liquid flows out of valve 314, it means that switch sleeve 313 has been successfully opened. Close valve 314 and continue to pressurize to the set pressure value and stabilize the pressure. Observe the value displayed by pressure sensor 315. If there is no change, it means that packer 312 is sealing well. The performance simulation test of switch sleeve 313 and packer 312 has been completed.

[0042] S5. Open valve 2 10 and drop a sealing ball into the injection pipe. The sealing ball will fall onto the ball seat of switch sleeve 2 9. Pressurize to the set value. If liquid flows out of valve 2 10, it means that switch sleeve 2 9 has been successfully opened. Close valve 2 10 and continue to pressurize to the set pressure. Then stabilize the pressure and observe the value displayed by pressure sensor 2 11. If there is no change, it means that packer 3 12 and packer 2 8 are both well sealed. Since the sealing performance of packer 3 12 has been verified in step S4, this step can verify the sealing performance of packer 2 8, which means that the performance simulation test of switch sleeve 2 9 and packer 2 8 is completed.

[0043] S6. Open valve 6 and insert a sealing ball into the injection pipe. The sealing ball will fall onto the ball seat of switch sleeve 5. Pressurize to the set value. If liquid flows out of valve 6, it means that switch sleeve 5 has been successfully opened. Close valve 6 and continue to pressurize to the set value. Then stabilize the pressure and observe the value displayed by pressure sensor 7. If there is no change, it means that packer 8 and packer 4 are both well sealed. Since the sealing performance of packer 8 has been verified in step S5, this step can verify the sealing performance of packer 4, which means that the performance simulation test of switch sleeve 5 and packer 4 is completed.

[0044] Understandably, in horizontal well staged fracturing technology, the setting ball and the sealing ball used to open the ball-dropping sleeve are generally made of low-density materials, such as nylon balls or hollow steel balls, so that they can be carried out of the well along with the fracturing flowback fluid, keeping the injection tubing full-bore. In this example, the horizontal well staged fracturing simulation test also used low-density materials to improve the accuracy of performance testing.

[0045] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the implementation of the present invention. Those skilled in the art will be able to make various obvious changes, readjustments, and substitutions without departing from the scope of protection of the present invention. It is neither necessary nor possible to exhaustively describe all embodiments here. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the claims of the present invention.

Claims

1. A horizontal well segmented fracturing simulation test device, characterized in that, include: A sleeve (1), the first end of which is open and the second end of which is closed; A sleeve fixing anchor (2) is configured to fix the sleeve (1); The fracturing string is disposed inside the casing (1) and includes an injection pipe and a setting ball seat (17), an anchor (16), multiple switch sleeves and a packer hanger (3) connected sequentially from the second end near the casing (1) to the first end of the casing (1) through the injection pipe. An annulus is formed between the injection pipe and the casing (1). A packer is fitted onto the injection tube and divides the annulus into multiple segments, with a switch sleeve installed in each closed annulus segment; Valves and pressure sensors are installed on the side wall of the sleeve (1) and correspond one-to-one with the switch sleeve.

2. The horizontal well segmented fracturing simulation test device according to claim 1, characterized in that, The number of the casing fixing anchors (2) shall not be less than two.

3. The horizontal well segmented fracturing simulation test device according to claim 1, characterized in that, The sleeve fixing anchor (2) is formed by two semi-circular retaining rings screwed together.

4. The horizontal well segmented fracturing simulation test device according to claim 1, characterized in that, The end of the injection tube is connected to a check valve (18).

5. The horizontal well segmented fracturing simulation test device according to claim 4, characterized in that, The inlet end of the flow valve (18) is connected to the guide shoe (19).

6. The horizontal well segmented fracturing simulation test device according to claim 1, characterized in that, The switch sleeves are configured to be 2-4 in number, wherein the switch sleeve closest to the end of the injection tube is a differential pressure sleeve, and the other switch sleeves are ball-throwing sleeves.

7. The horizontal well segmented fracturing simulation test device according to claim 1, characterized in that, The packer is a self-expanding packer.

8. A method for simulating fracturing in horizontal wells, characterized in that, The test is conducted using any of the horizontal well staged fracturing simulation test devices described in claims 1-7, and specifically includes the following steps: S1. Fix the casing (1) to the ground through the casing fixing anchor (2), and put the fracturing string into the casing (1); S2. The packer seals the annular space; S3. Connect the fracturing string to the external pressurization device, close all the valves, put in the setting ball, and start pressurization. After the setting ball enters the setting ball seat (17), the pressure rises to the set pressure value and stabilizes. The anchor (16) and the packer hanger (3) are set. Continue pressurization until the packer hanger (3) is released. Observe the pressurization pressure at this time. S4. Open the valve closest to the end of the injection tube, close the other valves, pressurize the injection tube to the set value, observe whether liquid flows out from the opened valve, close the valve, continue to pressurize to the set pressure value and stabilize the pressure, observe the value displayed by the pressure sensor connected to the valve; S5. Starting from the side closest to the end of the injection tube and moving away from the end of the injection tube, sequentially open the valves and switch sleeves of the other annular sections, observe whether liquid flows out from the opened valves, then close the valves and observe the value displayed by the pressure sensor connected to the valves.

9. The horizontal well segmented fracturing simulation test method according to claim 8, characterized in that, The switch sleeve closest to the end of the injection tube is the differential pressure sleeve, which is opened by applying pressure into the injection tube.

10. The horizontal well segmented fracturing simulation test method according to claim 9, characterized in that, Except for one differential pressure sleeve near the end of the injection tube, the other switch sleeves are ball-throwing sleeves, which are opened by throwing a ball into the injection tube and applying pressure.

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