Bridge plug slip simulation experiment system and experiment method

Abstract

The present application belongs to the technical field of oil and gas development experiment, and discloses a bridge plug sliding simulation experiment system and experiment method. The bridge plug sliding simulation experiment system comprises an experiment module, a water tank and a data acquisition and control module. The water tank forms a circulation loop with the experiment module through a liquid inlet pipeline and a reflux pipeline. The experiment module comprises an upper section of an experiment casing, a lower section of the experiment casing and a simulated bridge plug. The upper section of the experiment casing is sequentially provided from top to bottom with a reflux valve, a pressure sensor, an upper-section adjustable pressure relief valve and a shear pin. The simulated bridge plug is limited to the inside of the upper section of the experiment casing through the shear pin. A high-pressure pump and a first flowmeter are arranged on the liquid inlet pipeline, and a second flowmeter is arranged on the reflux pipeline. The pressure sensor, the high-pressure pump, the first flowmeter and the second flowmeter are all communicatively connected to the data acquisition and control module. The present application can realize the experimental simulation of bridge plug sliding and can capture the water hammer pressure signals generated thereby, thereby improving the accuracy of fault diagnosis of bridge plugs in fracturing operations.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of oil and gas development experiments, and particularly relates to a bridge plug sliding simulation experiment system and an experiment method. BACKGROUND

[0002] With the continuously increasing proportion of unconventional oil and gas production, unconventional oil and gas resources are gradually becoming the main body of oil and gas exploration and development in China. At present, horizontal well staged fracturing is the main means for the development of unconventional oil and gas resources. Bridge plugs, as downhole isolation tools, can prevent fracturing fluid from flowing between segments, and are essential downhole tools in staged fracturing construction.

[0003] In the prior art, indoor experiments of bridge plugs can analyze the setting ability, sealing effect and dissolution characteristics of the bridge plugs, and various series of bridge plugs are developed on this basis. The setting ability test of the bridge plug is usually carried out by means of hydraulic pressure, so that the bridge plug slips are eaten into the casing to simulate the setting process of the bridge plug. After the bridge plug is set, pressure is applied on one side of the experimental device to test the sealing performance of the bridge plug. With the increasing number of deep and ultra-deep wells, the influence of formation temperature on the bridge plug cannot be ignored, which increases the setting, pressure bearing, drilling and dissolution characteristics test of the bridge plug.

[0004] Due to factors such as deformation of the downhole casing, insufficient bridge plug setting force (release force), etc., the phenomenon of bridge plug sliding downhole occurs from time to time, which can eventually lead to the fracturing effect not meeting the expected effect and negatively affecting oil and gas production. In the early field test process, 82 segments were fractured in three wells, and suspected bridge plug sliding occurred 26 times, accounting for 31.7%. Timely and accurate judgment of the bridge plug sliding condition is crucial for subsequent adjustment of the fracturing method and guarantee of the fracturing construction effect. However, the existing technology cannot complete the laboratory simulation test of bridge plug sliding, so it is urgent to develop a bridge plug sliding indoor simulation experiment system to provide an experimental basis for accurate judgment of bridge plug sliding downhole. SUMMARY

[0005] The present application aims to provide a bridge plug sliding simulation experiment system and an experiment method to obtain the pressure signal characteristics in the bridge plug sliding process and improve the accuracy of the bridge plug sliding judgment in fracturing construction.

[0006] To achieve this purpose, the present application adopts the following technical solutions:

[0007] The bridge plug sliding simulation experiment system comprises:

[0008] The experiment module comprises an experimental upper casing segment, an experimental lower casing segment and a simulated bridge plug, the experimental upper casing segment is coaxially connected with the experimental lower casing segment, the experimental upper casing segment is sequentially provided from top to bottom with a backflow valve, a pressure sensor, an upper segment adjustable pressure relief valve and a shear pin, and the simulated bridge plug is arranged in the interior of the experimental upper casing segment and is limited by the shear pin;

[0009] a water tank, the water tank being connected to the liquid inlet of the upper section of the experimental sleeve through a liquid inlet pipeline, a high-pressure pump and a first flow meter being arranged on the liquid inlet pipeline; the backflow valve and the upper section adjustable pressure relief valve being connected to the water tank through a backflow pipeline respectively, a second flow meter being arranged on the backflow pipeline between the backflow valve and the water tank;

[0010] a data acquisition and control module, the pressure sensor, the high-pressure pump, the first flow meter and the second flow meter being communicatively connected to the data acquisition and control module.

[0011] Optionally, the lower section of the experimental sleeve is provided with a blocking ring, when the shear pin is sheared, the simulated bridge plug slips and is able to stop at the blocking ring after a certain distance of slip, the lower section of the experimental sleeve is used to simulate the re-anchoring state of the simulated bridge plug after slip.

[0012] Optionally, the lower section of the experimental sleeve is provided with a plurality of lower section adjustable pressure relief valves, the lower section adjustable pressure relief valves being connected to the water tank through the backflow pipeline, the plurality of lower section adjustable pressure relief valves being spirally distributed on the wall of the lower section of the experimental sleeve, the plurality of lower section adjustable pressure relief valves being located between the simulated bridge plug and the blocking ring, the lower section of the experimental sleeve being used to simulate the completely slipped state of the simulated bridge plug.

[0013] Optionally, the pressure sensor is provided with a plurality of pressure sensors, the wires of the plurality of pressure sensors being parallel to the axis of the upper section of the experimental sleeve.

[0014] Optionally, the upper section adjustable pressure relief valve is provided with a plurality of upper section adjustable pressure relief valves, the plurality of upper section adjustable pressure relief valves being spirally distributed along the outer wall of the upper section of the experimental sleeve, for simulating a plurality of perforations and fractures.

[0015] Optionally, the shear pin is provided with a plurality of shear pins, the plurality of shear pins being arranged at intervals along the circumference of the upper section of the experimental sleeve.

[0016] Optionally, the simulated bridge plug comprises:

[0017] a mandrel, a shear ring and a pressure-bearing blocking ring being arranged at intervals on the mandrel, the shear pin being arranged through the upper section of the experimental sleeve and located between the shear ring and the pressure-bearing blocking ring to define the position of the mandrel, the shear ring being capable of shearing the shear pin;

[0018] a rubber sleeve, the rubber sleeve being sleeved on the mandrel and abutting against the pressure-bearing blocking ring, a fastening nut being threadedly connected to the mandrel and pressing the rubber sleeve against the pressure-bearing blocking ring so that the rubber sleeve expands and is set in the upper section of the experimental sleeve.

[0019] Optionally, an adjustable pressure relief valve is arranged at the end of the lower section of the experimental casing away from the upper section of the experimental casing, and the adjustable pressure relief valve is connected with the water tank through the return pipeline.

[0020] The application further provides a bridge plug sliding simulation experiment method, which is based on the bridge plug sliding simulation experiment system.

[0021] S1, the data acquisition and control module controls the high-pressure pump to start, and water in the water tank is pumped into the upper section of the experimental casing, and the data acquisition and control module collects the flow value of the first flowmeter.

[0022] S2, the flow of the return valve is adjusted so that the internal fluid pressure of the upper section of the experimental casing is the experimental pressure and acts on the simulation bridge plug, and according to the experimental pressure, complete sliding simulation of the simulation bridge plug, simulation of the open state of the perforation, and simulation of the re-anchoring state of the simulation bridge plug after sliding can be realized.

[0023] Optionally, in step S2, when the lower section of the experimental casing is provided with a plurality of lower-section adjustable pressure relief valves and a blocking ring, the pressure relief threshold values of the upper-section adjustable pressure relief valve and the lower-section adjustable pressure relief valves are all higher than the shearing pressure of the shear pin, the flow of the return valve is adjusted so that the internal fluid pressure of the upper section of the experimental casing is a first experimental pressure, the first experimental pressure is higher than the shearing pressure of the shear pin and lower than the pressure relief threshold value of the upper-section adjustable pressure relief valve, the simulation bridge plug slides downward under the first experimental pressure, the shear pin is sheared, the simulation bridge plug slides into the lower section of the experimental casing and finally stops at the blocking ring, the data acquisition and control module collects the flow value of the second flowmeter on the return pipeline and the pressure value of the pressure sensor of the upper section of the experimental casing, and complete sliding simulation of the simulation bridge plug is realized.

[0024] Optionally, in step S2, the pressure relief threshold value of the upper-section adjustable pressure relief valve is set to be lower than the shearing pressure of the shear pin, the flow of the return valve is adjusted so that the internal fluid pressure of the upper section of the experimental casing is a second experimental pressure, the second experimental pressure is higher than the pressure relief threshold value of the upper-section adjustable pressure relief valve and lower than the shearing pressure of the shear pin, the upper-section adjustable pressure relief valve is opened under the action of the second experimental pressure, and water in the upper section of the experimental casing flows back to the water tank, and the open state of the perforation is simulated.

[0025] Optionally, in step S2, when the lower section of the experimental casing is only provided with the blocking ring, the pressure relief threshold of the upper section adjustable pressure relief valve is set to be higher than the shearing pressure of the shear pin, the flow of the backflow valve is adjusted so that the internal fluid pressure of the upper section of the experimental casing is a third experimental pressure, the third experimental pressure is lower than the pressure relief threshold of the upper section adjustable pressure relief valve and higher than the shearing pressure of the shear pin, after the shear pin is sheared, the simulated bridge plug slides into the lower section of the experimental casing for a distance, contacts the blocking ring and stops sliding, the internal fluid pressures of the upper section of the experimental casing and the lower section of the experimental casing gradually increase, when the internal fluid pressure is greater than the pressure relief threshold of the upper section adjustable pressure relief valve, the upper section adjustable pressure relief valve is opened, the internal fluid of the upper section of the experimental casing flows back to the water tank, and the simulation of the re-anchoring state of the simulated bridge plug after sliding is realized.

[0026] Advantages of the present application:

[0027] The bridge plug sliding simulation experiment system of the present application comprises an experimental module, a water tank and a data acquisition and control module, through the data acquisition and control module, experimental data including flow and pressure data can be collected in real time during the simulation experiment, which provides a reliable basis for bridge plug sliding identification; the water tank and the experimental module establish a water circulation pipeline through a liquid inlet pipeline and a backflow pipeline, the experimental module comprises an upper section of an experimental casing and a lower section of an experimental casing and a simulated bridge plug arranged inside the two, the upper section of the experimental casing is provided with a backflow valve, an upper section adjustable pressure relief valve and a pressure sensor, and the simulated bridge plug is fixed through a shear pin, the experimental pressure can be adjusted through the backflow valve, and in combination with the upper section adjustable pressure relief valve, indoor simulation of various downhole bridge plug states such as a gun opening state, a bridge plug completely sliding state and a bridge plug re-anchoring state after sliding can be realized, and the water hammer pressure signal generated in the upper section of the experimental casing can be captured through the pressure sensor during the experiment simulation, which provides an experimental basis for downhole bridge plug working state identification and improves the correctness of downhole bridge plug sliding judgment.

[0028] The bridge plug sliding simulation experiment method of the present application controls the high-pressure pump through the data acquisition and control module, and collects the flow data of the pressure sensor, the first flowmeter and the second flowmeter, and then realizes parameter monitoring in the sliding simulation process of the simulated bridge plug; the experimental pressure can be adjusted through the backflow valve, and indoor simulation of various downhole bridge plug states such as a gun opening state, a bridge plug completely sliding state and a bridge plug re-anchoring state after sliding can be realized by setting the pressure relief thresholds of the upper section adjustable pressure relief valve and the lower section adjustable pressure relief valve, and the water hammer pressure signal can be captured, which provides an experimental basis for downhole bridge plug working state identification and improves the correctness of bridge plug sliding judgment. BRIEF DESCRIPTION OF DRAWINGS

[0029] Figure 1 It is a structural schematic diagram of the bridge plug sliding simulation experiment system of the present application;

[0030] Figure 2 Structure diagram of experimental module involved in the present application;

[0031] Figure 3 Structure diagram of upper section of experimental sleeve in experimental module involved in the present application;

[0032] Figure 4 Structure diagram of full slip mode of lower section of experimental sleeve in experimental module involved in the present application;

[0033] Figure 5 Axial section view of Figure 4 ;

[0034] Figure 6 Structure diagram of re-anchoring mode of lower section of experimental sleeve in experimental module involved in the present application;

[0035] Figure 7 Axial section view of Figure 6 ;

[0036] Figure 8 Structure diagram of simulated bridge plug in experimental module involved in the present application;

[0037] Figure 9 Structure diagram of mandrel of simulated bridge plug involved in the present application;

[0038] Figure 10 Structure diagram of rubber sleeve of simulated bridge plug involved in the present application;

[0039] Figure 11 Axial section view of rubber sleeve of Figure 10 ;

[0040] Figure 12 Structure diagram of gland of simulated bridge plug involved in the present application;

[0041] Figure 13 Flow chart of bridge plug slip simulation experimental method of the present application.

[0042] In the drawings:

[0043] 1, experimental module; 11, experimental sleeve upper section; 111, inlet transition joint; 112, first connecting port; 113, second connecting port; 114, third connecting port; 115, fourth connecting port; 12, experimental sleeve lower section; 121, outlet transition joint; 122, adjustable pressure relief valve; 123, fifth connecting port; 124, blocking ring; 13, simulated bridge plug; 131, mandrel; 1311, shear ring; 1312, pressure-bearing blocking ring; 1313, inner hexagonal groove; 132, rubber sleeve; 1321, anti-escape collar; 1322, pre-deformation groove; 133, fastening nut; 134, gland; 1341, first clamping groove; 1342, second clamping groove; 14, backflow valve; 15, pressure sensor; 16, upper-section adjustable pressure relief valve; 17, shear pin; 18, lower-section adjustable pressure relief valve;

[0044] 2, water tank; 21, liquid inlet pipeline; 22, high-pressure pump; 23, first flow meter; 24, backflow pipeline; 25, second flow meter;

[0045] 3, data acquisition and control module; 31, control card; 32, calculator; 33, data cable. DETAILED DESCRIPTION

[0046] The application will be further described below in conjunction with the drawings and examples. It should be understood that the specific examples described herein are intended to be illustrative only and are not in any way limiting of the application. Furthermore, it should be understood that in the description, only parts pertinent to the application are shown in the drawings and not all structures.

[0047] In the description of the application, unless otherwise explicitly specified and limited, the terms "connected", "connected", "fixed" should be understood broadly, for example, it can be fixed connection, or detachable connection, or integrated; it can be mechanical connection, or electrical connection; it can be directly connected, or indirectly connected through an intermediate medium, or it can be the internal communication of two elements or the interaction relationship between two elements. For those skilled in the art, the specific meaning of the above terms in the application can be understood according to the specific circumstances.

[0048] In the present application, unless otherwise explicitly specified and limited, the "upper" or "lower" of the first feature to the second feature can include the direct contact of the first and second features, or can include the contact of the first and second features through another feature between them. Moreover, the "upper", "upper" and "upper" of the first feature to the second feature include the vertical and oblique above of the first feature to the second feature, or only indicate that the horizontal height of the first feature is higher than that of the second feature. The "below", "below" and "below" of the first feature to the second feature include the vertical and oblique below of the first feature to the second feature, or only indicate that the horizontal height of the first feature is less than that of the second feature.

[0049] In the description of the present embodiment, the terms "upper", "lower", "left", "right", and the like, orientation or positional relationship are based on the orientation or positional relationship shown in the drawings, and are only for the convenience of description and simplification of operation, and do not indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the present application. In addition, the terms "first" and "second" are only used to distinguish in the description, and have no special meaning.

[0050] As shown in Figures 1-3 The present embodiment provides a bridge plug sliding simulation experiment system, which comprises an experiment module 1, a water tank 2 and a data acquisition and control module 3. The experiment module 1 comprises an experiment casing upper section 11, an experiment casing lower section 12 and a simulated bridge plug 13. The experiment casing upper section 11 is coaxially connected with the experiment casing lower section 12. The experiment casing upper section 11 is sequentially provided from top to bottom with a backflow valve 14, a pressure sensor 15, an upper-section adjustable pressure relief valve 16 and a shear pin 17. The simulated bridge plug 13 is arranged inside the experiment casing upper section 11 and is limited by the shear pin 17. The water tank 2 is connected with a liquid inlet of the experiment casing upper section 11 through a liquid inlet pipeline 21. A high-pressure pump 22 and a first flow meter 23 are arranged on the liquid inlet pipeline 21. The backflow valve 14 and the upper-section adjustable pressure relief valve 16 are respectively connected to the water tank 2 through a backflow pipeline 24. A second flow meter 25 is arranged on the backflow pipeline 24 between the backflow valve 14 and the water tank 2. The pressure sensor 15, the high-pressure pump 22, the first flow meter 23 and the second flow meter 25 are all communicatively connected to the data acquisition and control module 3.

[0051] The bridge plug sliding simulation experiment system of the application can capture the water hammer pressure signal in the upper section of the experimental casing 11 in real time in different simulation experiment processes of the simulation bridge plug 13, and provide data support for monitoring different working states of the downhole bridge plug, so as to accurately determine the working state of the downhole bridge plug. The data acquisition and control module 3 is in communication connection with the high-pressure pump 22, so that the high-pressure pump 22 can be automatically started to realize automatic control of the experiment, and the experiment effect and precision control are improved. The data acquisition and control module 3 is in communication connection with the first flow meter 23 and the second flow meter 25, so that the liquid flow pumped into the upper section of the experimental casing 11 and the liquid flow flowing back to the water tank 2 can be monitored, so as to control the pressure of the internal fluid of the upper section of the experimental casing 11. The application realizes real-time acquisition of experimental data, including flow and pressure data, in the simulation experiment process, so as to obtain experimental parameters of the simulation bridge plug 13 in different working states, and provide reliable judgment basis for downhole bridge plug sliding identification. The water tank 2 and the experimental module 1 are connected through the liquid inlet pipeline 21 and the backflow pipeline 24 to form a water circulation loop. The experimental module 1 includes the upper section of the experimental casing 11, the lower section of the experimental casing 12 and the simulation bridge plug 13 arranged inside. The upper section of the experimental casing 11 is provided with the backflow valve 14, the upper section adjustable pressure relief valve 16 and the pressure sensor 15, and the simulation bridge plug 13 is fixed through the shear pin 17. The experimental pressure can be adjusted through the backflow valve 14, and the upper section adjustable pressure relief valve 16 and the lower section of the experimental casing 12 can be used to realize indoor simulation of various downhole bridge plug states, such as borehole opening state, complete sliding state of the simulation bridge plug 13 and re-anchoring state of the simulation bridge plug 13 after sliding. The water hammer pressure signal is collected in the experiment simulation process, and experimental basis is provided for downhole bridge plug working state identification, so as to improve the correct rate of downhole bridge plug sliding identification.

[0052] It is additionally explained that the high-pressure pump 22 is a large-displacement high-pressure pump, which serves as a power source for simulation of the sliding of the simulation bridge plug 13, and provides power for fluid circulation of the entire experimental system. The data acquisition and control module 3 includes a control card 31 and a calculator 32, which can control the working of the high-pressure pump 22 and control the experimental pressure according to the collected flow and pressure data and other parameters, such as flow difference, simulate the opening of the downhole borehole and fracture, simulate the pressure of the simulation fluid entering the formation, realize simulation of the opening state of the fracture, simulation of the re-anchoring state of the simulation bridge plug 13 after sliding, and simulation of the complete sliding state of the simulation bridge plug 13. The data acquisition and control module 3 is connected with the pressure sensor 15, the high-pressure pump 22, the first flow meter 23 and the second flow meter 25 through the data cable 33, and reliable data acquisition is realized.

[0053] As Figure 2As shown, the left end of the upper section 11 of the experimental sleeve is the liquid inlet, and an inlet adapter 111 is threadedly connected to the inlet. The inlet adapter 111 is connected to the liquid inlet pipe 21 via a union. The right end of the upper section 11 of the experimental sleeve is threadedly connected to the left end of the lower section 12 of the experimental sleeve, and the right end of the lower section 12 of the experimental sleeve is threadedly connected to the outlet adapter 121. The outlet adapter 121 is connected to the return pipe 24 to connect to the water tank 2. To facilitate the installation and connection of the return valve 14, pressure sensor 15, upper adjustable pressure relief valve 16, and shear stud 17, as follows... Figure 3 As shown, the upper section 11 of the experimental sleeve is provided with a first connection port 112, a second connection port 113, a third connection port 114, and a fourth connection port 115. Generally, the first connection port 112, the second connection port 113, the third connection port 114, and the fourth connection port 115 are threaded holes to facilitate connection and sealing. The reflux valve 14 is connected to the upper section 11 of the experimental sleeve through the first connection port 112. The reflux valve 14 is connected between the upper section 11 of the experimental sleeve and the water tank 2. By adjusting the opening of the reflux valve 14, the reflux flow rate and pressure can be adjusted, thereby achieving the adjustment of the experimental pressure.

[0054] This invention provides two forms of experimental sleeve lower section 12, corresponding to the complete sliding mode and re-anchoring mode of the simulated bridge plug 13, respectively. The experimental sleeve lower section 12 is threadedly connected to the experimental sleeve upper section 11, which facilitates quick disassembly and installation, so as to facilitate switching of experimental states.

[0055] Specifically, in the first case, only a blocking ring 124 is provided in the lower section 12 of the experimental sleeve, so that the bridge plug 13 can stop against the blocking ring 124 after sliding a certain distance, which is used to simulate the re-anchoring state of the bridge plug 13 after sliding.

[0056] like Figure 6 and Figure 7 As shown, the lower section 12 of the experimental sleeve has no openings on its sidewall, but its inner wall is equipped with a blocking ring 124. After sliding a certain distance, the simulated bridge plug 13 stops against the blocking ring 124, thus simulating the re-anchoring state. The blocking ring 124 is an annular protrusion on the inner wall of the lower section 12 of the experimental sleeve. The inner diameter of the blocking ring 124 is smaller than the outer diameter of the simulated bridge plug 13, thereby effectively blocking the simulated bridge plug 13.

[0057] The second type, such as Figure 4 and Figure 5 As shown, the lower section 12 of the experimental sleeve is equipped with multiple adjustable pressure relief valves 18 and a blocking ring 124. The adjustable pressure relief valves 18 are connected to the water tank 2 through the return pipe 24. The multiple adjustable pressure relief valves 18 are spirally distributed on the outer wall of the lower section 12 of the experimental sleeve. The second type of lower section 12 of the experimental sleeve is used to simulate the complete sliding state of the bridge plug 13.

[0058] likeFigure 4 A plurality of fifth connecting ports 123 are arranged on the side wall of the lower section 12 of the experimental casing, and the plurality of fifth connecting ports 123 can be threaded ports for threadedly connecting a plurality of lower-section adjustable pressure relief valves 18. The plurality of lower-section adjustable pressure relief valves 18 are spirally distributed on the outer wall of the lower section 12 of the experimental casing, and the direction of rotation is the same as that of the upper-section adjustable pressure relief valves 16. When the simulated bridge plug 13 slides, the plurality of lower-section adjustable pressure relief valves 18 are adjusted to simulate the situation of a plurality of perforations and fractures in the downhole staged fracturing process.

[0059] Optionally, a plurality of pressure sensors 15 are arranged, and the connecting lines of the plurality of pressure sensors 15 are parallel to the axis of the upper section 11 of the experimental casing.

[0060] The pressure sensor 15 is a high-precision high-frequency pressure sensor, which is used to collect the pressure fluctuation in the simulated state of various experimental pressures. The plurality of pressure sensors 15 are threadedly connected and installed at the plurality of second connecting ports 113 of the upper section 11 of the experimental casing, and are arranged at intervals. In this embodiment, two pressure sensors 15 are arranged. The pressure fluctuation signals collected by the two pressure sensors 15 are transmitted to the data acquisition and control module 3, and the pressure wave propagation speed and attenuation law can be analyzed. The second connecting port 113 is arranged downstream of the first connecting port 112, and the center connecting line of the two second connecting ports 113 is parallel to the axis of the upper section 11 of the experimental casing, that is, the connecting line of the installation positions of the two pressure sensors 15 is along the axial direction of the upper section 11 of the experimental casing. The two pressure sensors 15 are arranged at intervals, and the water hammer pressure signals generated in the upper section 11 of the experimental casing can be monitored, thereby providing experimental data basis for the working state recognition of the downhole bridge plug.

[0061] Optionally, a plurality of upper-section adjustable pressure relief valves 16 are arranged, and the plurality of upper-section adjustable pressure relief valves 16 are spirally distributed along the outer wall of the upper section 11 of the experimental casing, and are used to simulate a plurality of perforations and fractures.

[0062] As Figure 4 In this embodiment, the upper section 11 of the experimental casing is provided with a plurality of third connecting ports 114 for mounting a plurality of upper-section adjustable pressure relief valves 16. The upper-section adjustable pressure relief valves 16 are threadedly connected to the third connecting ports 114, and the third connecting ports 114 are in the form of spiral distribution, which can simulate the situation of a plurality of perforations and fractures. By adjusting the pressure relief threshold of the upper-section adjustable pressure relief valves 16, the rupture pressure of the formation at the perforation can be simulated.

[0063] Optionally, a plurality of shear pins 17 are arranged, and the plurality of shear pins 17 are arranged at intervals along the circumference of the upper section 11 of the experimental casing.

[0064] As Figure 4A plurality of fourth connecting ports 115 are circumferentially arranged at the right end of the upper section 11 of the experimental casing, and a plurality of shear pins 17 are respectively threadedly installed in the plurality of fourth connecting ports 115. The circumferentially distributed shear pins 17 are beneficial to uniformly supporting the limit simulation bridge plug 13, so that the bridge plug 13 has circumferentially balanced stress when subjected to fluid pressure, and are beneficial to the shearing of the shear pins 17. The end portions of the shear pins 17 are arranged in the interior of the experimental casing upper section 11, and the simulation bridge plug 13 is limited on the shear pins 17. The shear pins 17 can support the simulation bridge plug 13 on one hand, and on the other hand, the shear pins 17 can still be blocked at the fourth connecting ports 115 after being sheared, so as to avoid liquid leakage.

[0065] Optionally, the simulation bridge plug 13 comprises a mandrel 131 and a rubber sleeve 132. The shear ring 1311 and the pressure bearing ring 1312 are arranged at intervals on the mandrel 131. The shear pins 17 are arranged in the experimental casing upper section 11 and located between the shear ring 1311 and the pressure bearing ring 1312 to limit the position of the mandrel 131. The shear ring 1311 can shear the shear pins 17. The rubber sleeve 132 is sleeved on the mandrel 131 and abuts against the pressure bearing ring 1312. The fastening nut 133 is threadedly connected with the mandrel 131 and presses the rubber sleeve 132 on the pressure bearing ring 1312, so that the rubber sleeve 132 expands and is set in the experimental casing upper section 11.

[0066] As shown in Figure 8 and Figure 9 In this embodiment, the shear ring 1311 is arranged at the left end face of the mandrel 13 to bear the left end fluid pressure and can shear the shear pins 17 when the simulation bridge plug 13 slips in the simulation experiment. The pressure bearing ring 1312 is arranged at the right side of the shear ring 1311 and is spaced apart by a certain distance. The shear pins 17 arranged on the experimental casing upper section 11 can be inserted into the gap between the shear ring 1311 and the pressure bearing ring 1312, thereby limiting the initial installation position of the simulation bridge plug 13. At the same time, the pressure bearing ring 1312 is used to bear the rebound force of the rubber sleeve 132 when the simulation bridge plug 13 is compressed. An axial internal hexagonal groove 1313 is formed at the right end face of the mandrel 131. When the fastening nut 133 is threadedly connected with the mandrel 131, the internal hexagonal groove 1313 is used to provide a reaction force when the fastening nut 133 rotates in the setting process of the simulation bridge plug 13, so as to help the fastening nut 133 to be locked. When the fastening nut 133 is locked, the rubber sleeve 132 is pressed to deform and expand, thereby achieving setting. Preferably, the rubber sleeve 132 is respectively provided with a gland 134 at both ends, as shown in Figures 10-12The side wall edge of the gland 134 is provided with a first clamping groove 1341 for mounting an O-shaped sealing ring, the O-shaped sealing ring protrudes from the first clamping groove 1341, that is, the outer diameter of the O-shaped sealing ring is greater than the outer diameter of the first clamping groove 1341, when the rubber sleeve 132 is compressed and expanded and set, the O-shaped sealing ring is in close contact with the inner wall of the upper experimental casing section 11 or the inner wall of the lower experimental casing section 12 to achieve casing isolation. The end face of the gland 134 is provided with a second clamping groove 1342, and the two ends of the rubber sleeve 132 are respectively provided with anti-disengagement clamping rings 1321, when the gland 134 is mounted with the end of the rubber sleeve 132, the anti-disengagement clamping ring 1321 can be inserted into the second clamping groove 1342, thereby increasing the tightness between the rubber sleeve 132 and the gland 134, and preventing the rubber sleeve 132 from disengaging from the gland 134 after compression deformation. Further, as shown in Figure 11 The inner wall of the rubber sleeve 132 is provided with a pre-deformation groove 1322, the pre-deformation groove 1322 is coaxially arranged with the rubber sleeve 132 and the mandrel 13, when the fastening nut 133 is threadedly connected with the mandrel 131 and continuously screwed to the side of the pressure-bearing stop ring 1312, the fastening nut 133 gradually compresses the rubber sleeve 132, and the pre-deformation groove 1322 is beneficial to deformation of the rubber sleeve 132, so that the rubber sleeve 132 can be blocked or set in the upper experimental casing section 11.

[0067] Optionally, the lower experimental casing section 12 is provided with an adjustable pressure reducing valve 122 at one end away from the upper experimental casing section 11, and the adjustable pressure reducing valve 122 is connected with the water tank 2 through the backflow pipeline 24.

[0068] As shown in Figure 1 and Figure 2 , the right end of the lower experimental casing section 12 is threadedly connected with an outlet conversion joint 121, the adjustable pressure reducing valve 122 is connected with the outlet conversion joint 121, the adjustable pressure reducing valve 122 can adjust the relationship between pressure drop and flow, and the fluid in the lower experimental casing section 12 will be reduced in pressure to the pressure of the water tank 2 after flowing through the adjustable pressure reducing valve 122 and then backflows to the water tank 2.

[0069] The embodiment of the present application also provides a bridge plug sliding simulation experiment method, which can simulate complete sliding of the bridge plug 13, opening state of the perforation and re-anchoring state of the bridge plug 13 after sliding. It should be noted that before the simulation experiment of the bridge plug 13 is performed, the strength and material of the shear pin 17 need to be selected according to the simulation state of the experiment to be performed each time, so that the shear pin 17 can be sheared or not sheared in the experiment under different experimental pressures (internal fluid pressure of the upper experimental casing section 11). The shearing pressure of the shear pin 17 can be calculated according to the shear resistance of the shear pin 17. The experimental pressure control in the experimental process can be realized by adjusting the displacement of the high-pressure pump 22 and the flow of the backflow valve 14.

[0070] According to the bridge plug sliding simulation experiment system provided by the above embodiment, as shown in Figure 13The bridge slipping simulation experiment method shown in the flow chart comprises the following steps:

[0071] S1, the data acquisition and control module 3 controls the high-pressure pump 22 to start, pumps the water in the water tank 2 into the upper section 11 of the experimental casing, and the data acquisition and control module 3 collects the flow value of the first flowmeter 23;

[0072] S2, the flow of the backflow valve 14 is adjusted so that the internal fluid pressure of the upper section 11 of the experimental casing is the experimental pressure, the experimental pressure acts on the simulated bridge plug 13, and the simulation experiment of the completely slipping state, the perforation opening state and the re-anchoring state after slipping of the simulated bridge plug 13 is realized.

[0073] Among them, part of the water in the upper section 11 of the experimental casing flows back to the water tank 2 through the backflow valve 14, and the other part generates the experimental pressure on the simulated bridge plug 13; the adjustable pressure reducing valve 122 is adjusted so that its working pressure drop is lower than the shearing pressure of the shear pin 17.

[0074] Completely slipping state simulation: the lower section 12 of the experimental casing adopts the second kind, and the lower section 12 of the experimental casing is provided with a plurality of lower section adjustable pressure relief valves 18 and a blocking ring 124. In step S2, the pressure relief thresholds of the upper section adjustable pressure relief valve 16 and the lower section adjustable pressure relief valve 18 are both higher than the shearing pressure of the shear pin 17; the flow of the backflow valve 14 is adjusted so that the internal fluid pressure of the upper section 11 of the experimental casing is the first experimental pressure, which is greater than the shearing pressure of the shear pin 17 and less than the pressure relief threshold of the upper section adjustable pressure relief valve 16. The simulated bridge plug 13 slides downward and abuts against the shear pin 17 under the first experimental pressure, until the shear pin 17 is sheared off, the simulated bridge plug 13 slides into the lower section 12 of the experimental casing and finally stops against the blocking ring 124; the data acquisition and control module 3 collects the flow value of the second flowmeter 25 on the backflow pipeline 24 and the pressure value of the pressure sensor 15 of the upper section 11 of the experimental casing, and realizes the complete slipping simulation of the simulated bridge plug 13. Among them, after the shear pin 17 is sheared off, the water hammer pressure signal generated in the upper section 11 of the experimental casing is detected by the pressure sensor 15 and sent to the data acquisition and control module 3.

[0075] Perforation opening state simulation: In step S2, the pressure relief threshold of the upper adjustable pressure relief valve 16 is set to be lower than the shearing pressure of the shear pin 17, and the flow rate of the backflow valve 14 is adjusted so that the internal fluid pressure of the upper experimental casing section 11 is a second experimental pressure, which is higher than the pressure relief threshold of the upper adjustable pressure relief valve 16 and lower than the shearing pressure of the shear pin 17. When the mandrel 131 of the simulation bridge plug 13 moves to contact the shearing ring 1311 with the shear pin 17, the internal pressure of the upper experimental casing section 11 increases. Since the pressure relief threshold of the upper adjustable pressure relief valve 16 is lower than the shearing pressure of the shear pin 17, the upper adjustable pressure relief valve 16 is automatically opened under the action of the second experimental pressure, and the liquid in the upper experimental casing section 11 flows back to the water tank 2 through the adjustable pressure relief valve 16 and the backflow pipeline 24, thereby realizing the simulation of the perforation opening state, and the experimental system is closed after the simulation. In the perforation opening state simulation experiment, the lower experimental casing section 12 can be in a complete slippage mode or a re-anchoring mode. The water hammer pressure signal generated by the flow of the upper adjustable pressure relief valve 16 is detected by the pressure sensor 15 and uploaded to the data acquisition and control module 3.

[0076] Slippage and re-anchoring simulation: The lower experimental casing section 12 adopts the first type and is only provided with the blocking ring 124. In step S2, the upper adjustable pressure relief valve 16 is set to be higher than the shearing pressure of the shear pin 17, and the flow rate of the backflow valve 14 is adjusted so that the internal fluid pressure of the upper experimental casing section 11 is a third experimental pressure, which is lower than the pressure relief threshold of the upper adjustable pressure relief valve 16 and higher than the shearing pressure of the shear pin 17. The simulation bridge plug 13 moves to the right under the action of the third experimental pressure, and when the shearing ring 1311 contacts the shear pin 17, the shear pin 17 is sheared, and the fluid in the upper experimental casing section 11 pushes the simulation bridge plug 13 to slip. When the simulation bridge plug 13 slips a distance and contacts the blocking ring 124 in the lower experimental casing section 12, it stops slipping, and then the internal fluid pressure of the lower experimental casing section 12 and the upper experimental casing section 11 gradually increases. When the internal fluid pressure is greater than the pressure relief threshold of the upper adjustable pressure relief valve 16, the upper adjustable pressure relief valve 16 is opened, and the fluid in the casing (including the upper experimental casing section 11 and the lower experimental casing section 12) flows back to the water tank 2, thereby realizing the simulation of the re-anchoring state of the simulation bridge plug 13 after slippage, and the experimental system is closed after the simulation.

[0077] The bridge plug sliding simulation experiment method of the present application controls the high-pressure pump 22 through the data acquisition and control module 3, and acquires pressure fluctuation data of the pressure sensor 15 and flow data of the first flow meter 23 and the second flow meter 25, thereby realizing performance parameter detection and overall control of the simulation bridge plug 13 sliding simulation process; the experiment pressure can be adjusted through the backflow valve 14, and the pressure relief threshold of multiple upper adjustable pressure relief valves 16 can be set at the same time, thereby realizing indoor simulation of the perforation opening state, the complete sliding state of the simulation bridge plug 13, and the re-anchoring state of the simulation bridge plug 13 after sliding, and the water hammer pressure signal generated in the casing during the simulation experiment can be captured, which is embodied as a pressure fluctuation signal, providing an experimental basis for downhole bridge plug working state recognition, and being beneficial to improving the correctness of downhole bridge plug sliding state judgment or recognition during fracturing construction.

[0078] Obviously, the above embodiments of the present application are only examples for clearly illustrating the present application, and are not intended to limit the embodiments of the present application. Those skilled in the art can make various obvious changes, readjustments and substitutions without departing from the protection scope of the present application. It is unnecessary and impossible to enumerate all the embodiments. Any modification, equivalent substitution and improvement within the spirit and principle of the present application shall be included in the protection scope of the claims of the present application.

Claims

1. A bridge plug slip simulation experiment system, characterized in that, The experimental module (1) comprises an experimental sleeve upper section (11), an experimental sleeve lower section (12) and a simulated bridge plug (13), the experimental sleeve upper section (11) is coaxially connected with the experimental sleeve lower section (12), the experimental sleeve upper section (11) is sequentially provided with a backflow valve (14), a pressure sensor (15), an upper-section adjustable pressure relief valve (16) and a shear pin (17) from top to bottom, the simulated bridge plug (13) is arranged in the experimental sleeve upper section (11) and is limited by the shear pin (17); the experimental sleeve lower section (12) is provided with a blocking ring (124), when the shear pin (17) is sheared, the simulated bridge plug (13) slips and can stop at the blocking ring (124) after slipping for a distance, and the experimental sleeve lower section (12) is used for simulating the re-anchoring state of the simulated bridge plug (13) after slipping; a water tank (2) is connected with a liquid inlet of the experimental sleeve upper section (11) through a liquid inlet pipeline (21), a high-pressure pump (22) and a first flowmeter (23) are arranged on the liquid inlet pipeline (21); the backflow valve (14) and the upper-section adjustable pressure relief valve (16) are respectively connected to the water tank (2) through a backflow pipeline (24), and a second flowmeter (25) is arranged on the backflow pipeline (24) between the backflow valve (14) and the water tank (2); a data acquisition and control module (3), the pressure sensor (15), the high-pressure pump (22), the first flowmeter (23) and the second flowmeter (25) are all communicatively connected to the data acquisition and control module (3). The experimental sleeve lower section (12) is provided with a plurality of lower-section adjustable pressure relief valves (18), the lower-section adjustable pressure relief valves (18) are connected to the water tank (2) through the backflow pipeline (24), the plurality of lower-section adjustable pressure relief valves (18) are spirally distributed on the pipe wall of the experimental sleeve lower section (12), the plurality of lower-section adjustable pressure relief valves (18) are located between the simulated bridge plug (13) and the blocking ring (124), and the experimental sleeve lower section (12) is used for simulating the completely slipped state of the simulated bridge plug (13).

2. The bridge plug slip analog experiment system of claim 1, wherein, A plurality of pressure sensors (15) are arranged, and the connecting lines of the plurality of pressure sensors (15) are parallel to the axis of the experimental sleeve upper section (11).

3. The bridge plug slip analog experiment system of claim 1, wherein, A plurality of upper-section adjustable pressure relief valves (16) are arranged, and the plurality of upper-section adjustable pressure relief valves (16) are spirally distributed along the outer wall of the experimental sleeve upper section (11) and are used for simulating a plurality of perforations and cracks.

4. The bridge plug slip analog experiment system of claim 3, wherein, A plurality of shear pins (17) are arranged, and the plurality of shear pins (17) are arranged at intervals in the circumferential direction of the experimental sleeve upper section (11).

5. The bridge plug slip analog experiment system of claim 4, wherein, The simulated bridge plug (13) comprises:

6. The bridge plug slip analog experiment system of claim 1, wherein, ​ A core shaft (131) is provided with a shear ring (1311) and a pressure bearing ring (1312) at intervals, the shear pin (17) is arranged on the experimental casing upper section (11) and located between the shear ring (1311) and the pressure bearing ring (1312) to define the position of the core shaft (131), and the shear ring (1311) can shear the shear pin (17); A rubber sleeve (132) is sleeved on the core shaft (131) and abuts against the pressure bearing ring (1312), a fastening nut (133) is threadedly connected with the core shaft (131) and presses the rubber sleeve (132) on the pressure bearing ring (1312) so that the rubber sleeve (132) is expanded and set in the experimental casing upper section (11).

7. The bridge plug slip analog experiment system of claim 3, wherein, The experimental casing lower section (12) is provided with an adjustable pressure relief valve (122) at an end away from the experimental casing upper section (11), and the adjustable pressure relief valve (122) is connected with the water tank (2) through the return pipeline (24).

8. A method of simulating the sliding of a bridge plug, characterized by, The bridge plug sliding simulation experiment system according to any one of claims 1-7, the bridge plug sliding simulation experiment method comprising the following steps: S1, the data acquisition and control module (3) controls the high-pressure pump (22) to start, and pumps the water in the water tank (2) into the experimental casing upper section (11), and the data acquisition and control module (3) acquires the flow value of the first flowmeter (23); S2, the flow of the return valve (14) is adjusted so that the internal fluid pressure of the experimental casing upper section (11) is the experimental pressure and acts on the simulation bridge plug (13), and according to the experimental pressure, the complete sliding simulation of the simulation bridge plug (13), the simulation of the open state of the perforation, and the simulation of the re-anchoring state of the simulation bridge plug (13) after sliding can be realized respectively.

9. The bridge plug slip analog experiment method of claim 8, wherein, In step S2, when the experimental casing lower section (12) is provided with a plurality of lower-section adjustable pressure relief valves (18) and a blocking ring (124), the pressure relief threshold values of the upper-section adjustable pressure relief valve (16) and the lower-section adjustable pressure relief valves (18) are all higher than the shearing pressure of the shear pin (17), the flow of the return valve (14) is adjusted so that the internal fluid pressure of the experimental casing upper section (11) is a first experimental pressure, the first experimental pressure is higher than the shearing pressure of the shear pin (17) and lower than the pressure relief threshold values of the upper-section adjustable pressure relief valve (16) and the lower-section adjustable pressure relief valves (18), the simulation bridge plug (13) slides downward at the first experimental pressure, the shear pin (17) is sheared, the simulation bridge plug (13) slides into the experimental casing lower section (12) and finally stops against the blocking ring (124); the data acquisition and control module (3) acquires the flow value of the second flowmeter (25) on the return pipeline (24) and the pressure value of the pressure sensor (15) of the experimental casing upper section (11), and the complete sliding simulation of the simulation bridge plug (13) is realized.

10. The bridge plug slip analog experiment method of claim 8, wherein, In step S2, the pressure relief threshold of the upper adjustable pressure relief valve (16) is set to be lower than the shearing pressure of the shear pin (17), the flow of the backflow valve (14) is adjusted so that the internal fluid pressure of the upper experimental casing section (11) is a second experimental pressure, which is higher than the pressure relief threshold of the upper adjustable pressure relief valve (16) and lower than the shearing pressure of the shear pin (17), the upper adjustable pressure relief valve (16) is opened under the action of the second experimental pressure, and the water in the upper experimental casing section (11) flows back to the water tank (2), thereby achieving simulation of the open state of the perforation.

11. The bridge plug slip analog experiment method of claim 8, wherein, In step S2, when the lower experimental casing section (12) is only provided with the blocking ring (124), the pressure relief threshold of the upper adjustable pressure relief valve (16) is set to be higher than the shearing pressure of the shear pin (17), the flow of the backflow valve (14) is adjusted so that the internal fluid pressure of the upper experimental casing section (11) is a third experimental pressure, which is lower than the pressure relief threshold of the upper adjustable pressure relief valve (16) and higher than the shearing pressure of the shear pin (17), after the shear pin (17) is sheared, the simulation bridge plug (13) slides into the lower experimental casing section (12) and contacts the blocking ring (124) and stops sliding after sliding a distance, the internal fluid pressure of the upper experimental casing section (11) and the lower experimental casing section (12) gradually increases, when the internal fluid pressure is greater than the pressure relief threshold of the upper adjustable pressure relief valve (16), the upper adjustable pressure relief valve (16) is opened, the internal fluid of the upper experimental casing section (11) flows back to the water tank (2), and simulation of the re-anchoring state of the simulation bridge plug (13) after sliding is achieved.

Images