Piston type explosion energy testing device

Abstract

The invention discloses a piston type explosion energy testing device which comprises a body, the body is sequentially provided with an explosion cavity, a piston cavity and a liquid acting cavity which are communicated from top to bottom, the top of the explosion cavity is provided with an igniter, one side of the explosion cavity is provided with a gas injection port, a rock core placer is arranged in the piston cavity, and the rock core placer and the piston cavity form a piston structure. A liquid injection port and a liquid discharge port are formed in the positions, close to the bottom, of the liquid acting cavity, and the liquid discharge port is connected with an acting observation cavity through a pipeline. Through a series of energy conversion, the device can be used for high-concentration explosion capacity test and has safety. The invention also discloses an explosion fracturing energy test method, which is divided into two modes of placing the rock core and not placing the rock core, and according to the explosion effect of the rock core in the gas, the dynamic parameters of the explosion energy under different concentrations are determined and obtained. And test parameters can be obtained under the conditions of different pressures and different concentration ratios under the condition that the rock core is not used.

Description

Technical Field

[0001] The invention belongs to the technical field of explosive fracturing, relates to a piston-type explosive energy testing device, and also relates to an explosive fracturing energy testing method. Background Art

[0002] With the development of unconventional oil and gas, represented by shale gas, high-fluid volumetric fracturing is increasingly becoming the primary method for increasing production through fracturing of unconventional oil and gas. Horizontal well fracturing technology consumes a lot of water. Furthermore, the fracturing fluid requires the addition of multiple chemicals, posing a risk of environmental pollution. Large-scale hydraulic fracturing will exacerbate local water shortages and the risk of environmental pollution. Air explosion volumetric fracturing involves injecting air into the formation at high pressure. Using an appropriate detonation method, the injected air and methane in the formation undergo a violent explosion. The high pressure generated by the explosion fractures the formation, and the cracks extend under the influence of the high pressure generated by the flame and the shock wave of the explosion, forming a complex fracture network with a certain degree of conductivity.

[0003] At present, the test equipment used for explosive fracturing to test the effect of explosive energy on rock cores is simple, and mainly uses sealed metal balls for ignition tests to observe the degree of damage to the rock core caused by the explosive energy. This method requires high specifications for the metal sealing balls, a single test method, and high test costs, and can only test the effect of the explosion on the rock core. Due to the high risk of the test, it is impossible to repeatedly conduct explosive tests on rocks in a pressurized closed-loop space, and it is impossible to test the explosive medium in an environment without a rock core for comparison. The high risk makes it impossible to release or transform the accumulated capacity of the original equipment, making it impossible to conduct high-energy tests, and thus it is impossible to simulate the explosive force of the formation under the pressurized state in the well during the process of injecting gas and other media in a simulated formation environment.

[0004] Patent publication number CN111894550A discloses a simulation test system and method for cryogenic fluid fracturing in upward boreholes. This system effectively allows the cryogenic fluid to fully act on the upward borehole wall for cryogenic fluid fracturing, provides comprehensive data measurement throughout the entire cryogenic fracturing process, and ensures safety throughout the test. However, this system still cannot simulate gas injection pressures under formation conditions and cannot test the effects of explosions on rock in various environments. Summary of the Invention

[0005] In view of the deficiencies in the prior art, the present invention aims to provide a piston-type explosive energy test device to produce a fitting effect between core testing and the medium.

[0006] To achieve the above object, the present invention adopts the following technical solutions:

[0007] A piston-type explosive energy testing device comprises a main body, wherein the main body is provided with an explosion chamber, a piston chamber, and a liquid working chamber which are connected from top to bottom in sequence, a rear cylinder cover is provided at the bottom of the liquid working chamber, the rear cylinder cover is sealed with the main body, an igniter is provided at the top of the explosion chamber, a gas injection port is provided on one side of the explosion chamber, a gas injection pipe is provided at the gas injection port, the gas injection pipe is connected with the explosion chamber, a first switch and an injection-type one-flow valve are provided on the gas injection pipe, a core placer is provided in the piston chamber, the core placer and the piston chamber form a piston structure, a shear pin is provided on the main body which is arranged corresponding to the bottom of the piston chamber, a liquid injection port and a liquid discharge port are respectively provided at the bottom of the liquid working chamber, and a working observation chamber is connected to the liquid discharge port through a pipeline.

[0008] In some embodiments, a pressure gauge and a thermometer are further provided on the top of the explosion chamber.

[0009] In some embodiments, a liquid injection pipe is provided at the liquid injection port, a second switch is provided on the liquid injection pipe, and an observation window is provided at the liquid working chamber.

[0010] In some embodiments, the liquid inlet and liquid outlet are respectively arranged on both sides of the liquid working chamber, a pressure gauge is also provided below the liquid outlet, and a one-way valve and a third switch are provided on the pipeline connected to the liquid outlet.

[0011] In some embodiments, the work observation chamber includes two upper and lower cavities, which are separated by a piston body. The cavity located below the piston body and connected to the liquid work chamber is a liquid cavity, and a pressure relief port is provided at the bottom of the liquid cavity. The cavity located above the piston body is an air cavity, and an air injection port is provided.

[0012] In some embodiments, a pressure gauge and a safety valve are provided at the top of the air cavity, an air injection pipe communicating with the air cavity is provided at the air injection port, a fourth switch is provided on the air injection pipe, a pressure relief pipe communicating with the liquid cavity is provided at the pressure relief port, and a fifth switch is provided on the pressure relief pipe.

[0013] The present invention also provides an explosive fracturing energy testing method, which includes two methods: placing a core and not placing a core: placing a core in a core placer, performing an explosion test on the core by exploding gases of different concentrations in an explosion chamber and releasing explosive potential energy, and obtaining explosion energy data under different gas concentrations; when no core is loaded, only the core placer is loaded, performing an explosion of gases of different concentrations in the explosion chamber and releasing explosive potential energy, and comparing the relationship between the piston movement stroke in the work observation chamber and the temperature and pressure in the explosion chamber, and obtaining a linear relationship between the explosion capacity under different concentrations.

[0014] In some embodiments, the explosive fracturing energy test method comprises the following steps:

[0015] S1. Open the rear cylinder cover of the liquid working chamber, remove the core placing device, place the core and the metal support device in the core placing device, replace them in the piston chamber, and seal the rear cylinder cover;

[0016] S2. Inject pressure P1 into the air cavity of the working observation cavity so that the piston body of the working observation cavity is pushed into the bottom, and inject liquid into the liquid injection port of the liquid working cavity to form pressure P2, and P1>P2. The pressure in P2 is sufficient to lift the core placer to the predetermined position, and inject gas or liquid into the explosion cavity. By controlling the concentration and ignition method, the pressure causes the gas in the explosion cavity to explode and release the explosion potential energy, which serves as an explosion test for the core. The explosion potential energy works on the liquid in the liquid working cavity through the core placer, so that the explosion potential energy is converted into mechanical energy and then works on the liquid again. The liquid is allowed to enter the liquid cavity of the working observation cavity through the connecting pipeline, and the gas in the equilibrium state is compressed and worked. The explosion energy data is quantitatively obtained through the piston body in the working observation cavity.

[0017] In some embodiments, the explosive fracturing energy test method comprises the following steps:

[0018] S1. Open the rear cylinder cover of the liquid working chamber, remove the core placer, place the core and the metal support device in the core placer, re-insert it into the piston chamber, and seal the rear cylinder cover;

[0019] S2. Inject pressure P1 into the air cavity in the working observation chamber so that the piston of the working observation chamber is pushed into the bottom, and inject liquid into the liquid filling port in the liquid working chamber to form pressure P2, and P1>P2. The pressure in P2 is enough to lift the core placer to the predetermined position, and insert shear pins into the entire cavity body and the internal core placer (piston). The shear force τ1 of the pin is selected to be less than 50% of the stress τ2 of the entire metal component, and τ1>τ2*50%, so that the liquid in the liquid cavity of the working observation chamber is discharged, the piston is flexible, and the channel switch in the liquid working chamber and the working observation chamber is opened to ensure the balance of the entire device. At this time, the corresponding mixed gas is injected into the explosion chamber to determine the injection pressure P3 in the explosion chamber, the gas cavity in the work observation chamber is injected with pressure P1, and the liquid is injected into the liquid injection port in the liquid work chamber to make it pressure P2, so that P1>P2>P3, and the switch in the explosion chamber is turned off. The whole device is fixed, and the explosion is ignited. The pressure causes the gas in the explosion chamber to explode and release the explosion potential energy, which serves as an explosion test for the core. The explosion potential energy works on the liquid in the liquid work chamber through the core placer, so that the explosion potential energy is converted into mechanical energy and then works on the liquid again. The liquid is allowed to enter the liquid cavity of the work observation chamber through the connecting pipeline, and the gas in the equilibrium state is compressed and worked. The explosion energy data is quantitatively obtained through the piston body in the work observation chamber.

[0020] In some embodiments, the explosive fracturing energy test method comprises the following steps:

[0021] S1. Open the rear cylinder cover of the liquid working chamber, remove the core loader, and install the core loader without the core in the core loader. Place the corresponding metal liner block in its slot and place it inside the device cavity. Put it back into the piston cavity and seal the rear cylinder cover.

[0022] S2. Inject pressure P1 into the air cavity in the working observation chamber so that the piston of the working observation chamber is pushed to the bottom. Inject liquid into the liquid filling port of the liquid working chamber to form a pressure P2, and P1>P2. The pressure in P2 is sufficient to lift the core placer to the predetermined position. Inject gas (liquid) into the explosion cavity. By controlling the concentration, ignition, etc., the pressure causes the gas in the cavity to explode and release the explosion potential energy. By observing the working observation chamber and comparing the relationship between the piston movement stroke in the working observation chamber and the temperature and pressure in the explosion chamber, a linear relationship between the explosion capacity under different concentrations is obtained.

[0023] The beneficial effects of the present invention are:

[0024] The present invention provides a piston-type explosion energy test device and an explosion fracturing energy test method. The explosion chamber simulates the effect of one or more repeated explosions of explosive energy on the reservoir in a formation environment. The piston chamber converts the energy in the upper explosion chamber from the explosion potential energy into mechanical energy. The liquid working chamber converts the mechanical energy into liquid compression potential energy. Since the liquid compression energy can be ignored in this device, it is transmitted to the next working observation chamber through the liquid working. The observation window of the liquid working chamber can observe the movement stroke of the core placer (piston) and the equipment status. Through a series of energy conversions, the test device of the present invention can perform high-concentration explosion capacity tests and has safety.

[0025] The explosive fracturing energy test method is divided into two specific methods: core placement and non-core placement. The purpose is to obtain a dynamic parameter of the explosive energy at different concentrations after the core's explosive effect in the gas has been determined. Furthermore, without the use of cores, test parameters can be obtained under different pressures and concentration ratios. The gas concentration can be pre-calculated and set in this test device. Explosion tests are then conducted under simulated formation conditions, simulating the injection pressure and concentration. This allows for testing the effects of explosions on rock in various environments while also meeting safety requirements during the test.

[0026] The above description is only an overview of the technical solution of the present invention. In order to more clearly understand the technical means of the present invention and implement it according to the contents of the specification, the following is a detailed description of the preferred embodiments of the present invention with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following is a brief introduction to the drawings required for use in the specific embodiments or the description of the prior art. Obviously, some of the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0028] Figure 1 It is a structural schematic diagram of a piston-type explosive energy test device of the present invention;

[0029] Figure 2 It is a partial schematic diagram of a shear pin in a piston-type explosive energy test device of the present invention;

[0030] Figure 3 The present invention is a top view of the lower portion of a liquid working chamber in a piston-type explosive energy testing device.

[0031] Among them, the labels of various components are as follows:

[0032] 1. Explosion chamber; 11. Igniter; 12. Injection check valve; 2. Core placer; 21. Core; 22. Metal backing; 3. Piston chamber; 31. Shear pin; 32. Pin shear puller; 33. Inner wall of piston chamber; 4. Liquid working chamber; 41. Observation window; 42. Liquid injection port; 43. Rear cylinder head; 44. Check valve; 45. Step surface; 46. Connecting pipeline; 5. Working observation chamber; 51. Liquid chamber; 52. Gas chamber; 53. Piston body; 54. Pressure relief port; 55. Gas injection port. DETAILED DESCRIPTION

[0033] In order to better describe the present invention, the following is further illustrated by specific examples. The methods in the following examples are conventional methods unless otherwise specified.

[0034] Unless otherwise specified, the technical solutions described in the present invention are all conventional solutions in the field; the reagents or materials described are all from commercial channels unless otherwise specified.

[0035] The present invention provides a piston-type explosive energy test device, such as Figure 1 As shown, the body includes a main body, which is provided with a connected explosion chamber 1, a piston chamber 3, and a liquid working chamber 4 from top to bottom. A rear cylinder cover 43 is provided at the bottom of the liquid working chamber 4, and the rear cylinder cover 43 is sealed with the body. An igniter 11 is provided at the top of the explosion chamber 1, and a gas injection port is provided on one side of the explosion chamber 1. A core 21 placer 2 is provided in the piston chamber 3, and the core 21 placer 2 and the piston chamber 3 form a piston structure. A liquid injection port and a liquid discharge port are respectively provided near the bottom of the liquid working chamber 4, and the liquid discharge port is connected to the working observation chamber 5 through a metal pressure pipeline.

[0036] The top of the explosion chamber 1 on the main body is thickened and flat. A pressure gauge and a thermometer are also provided on the top of the explosion chamber 1. A gas injection pipe is provided at the gas injection port of the explosion chamber 1. The gas injection pipe is connected to the explosion chamber 1. Two switches and an injection-type one-flow valve 12 are provided on the gas injection pipe.

[0037] The explosion chamber 1 is spherical, ensuring that the entire chamber receives equivalent pressure during the explosion process, and forms energy conversion through the lower core 21 placer 2 (piston). At the same time, the entire explosion energy can only be conducted to the weak area core 21 placer 2 (piston) and realize energy conversion.

[0038] The core 21 placer 2 is cylindrical, with a bottom diameter larger than the upper diameter. The inner wall 33 of the piston chamber 3 and the outer wall of the core 21 placer 2 are smooth and of equal diameter. The bottom of the core 21 placer 2 (piston) is connected to the liquid working chamber 4. The inside of the core 21 placer 2 is a groove, the bottom of which is the same width as the inner wall of the lower liquid working chamber 4 and is sealed. Cores 21 of different lengths can be placed in the groove. The core 21 in the groove can be placed as needed. The length and number of segments and the length of the core 21 can be changed according to experimental needs. The shortened part is filled with metal filler. If the core 21 needs to be partially exposed for a corresponding length, the groove at the bottom of the core 21 can be filled with a metal liner 22 to expose the core 21 partially to the explosion chamber 1, so that the explosion energy in the upper explosion chamber 1 acts on the core 21.

[0039] like Figure 2 As shown, a shear pin 31 (limit pin) is provided on the main body located at the bottom of the piston chamber 3. The shear pin 31 selects a shear force τ1 that is less than 50% of the stress τ2 of the entire metal component, and its τ1>τ2*50%. A pin shear pull-out spiral interface is provided at the bottom, and a pin shear puller is made. During the placement of the shear pin 31, the shear pin 31 is stuck with the inner wall 33 of the piston chamber 3 under an abnormal state. In this state, the core 21 placer 2 (piston) can be withdrawn by turning the knob of the pin shear puller.

[0040] like Figure 3 As shown, a liquid injection pipe is provided at the liquid injection port of the liquid working chamber 4, and two switches are provided on the liquid injection pipe. The liquid injection port and the liquid discharge port are respectively provided on both sides of the liquid working chamber 4, and a pressure gauge is also provided below the liquid discharge port. A one-way valve 44 and a switch are provided on the pipeline connected to the liquid discharge port. Liquid is injected from the liquid injection port and can withstand pressure. The pressure is transmitted to the working observation chamber 5 and compared with the pressure in the air cavity 52 in the working observation chamber 5 to determine the pressure size for resetting the core 21 placer 2 (piston). The overflowing liquid flows into the working observation chamber 5. The one-way valve 44 ensures that the liquid in the liquid working chamber 4 does not flow back and the pressure drops.

[0041] An observation window 41 is provided at the liquid working chamber 4, and the observation window 41 helps to observe the movement trajectory and limit situation of the bottom of the core 21 placement device 2 (piston).

[0042] The working observation chamber 5 includes two upper and lower cavities, which are separated by a piston body 53. The cavity located below the piston body 53 and connected to the liquid working chamber 4 is the liquid chamber 51. A pressure relief port 54 is provided at the bottom of the liquid chamber 51. The cavity located above the piston body 53 is the air chamber 52. The air chamber 52 is provided with an air injection port 55. The overflowing liquid is squeezed into the working observation chamber 5 to increase the pressure in the liquid chamber 51 of the working observation chamber 5, breaking the gas-liquid balance in the cavity. The value of the explosion energy is obtained by observing the piston displacement in the working observation chamber 5, forming a functional relationship.

[0043] A pressure gauge and a safety valve are provided at the top of the air cavity 52, an air injection pipe communicating with the air cavity 52 is provided at the air injection port 55, and a switch is provided on the air injection pipe, and a pressure relief pipe communicating with the liquid cavity 51 is provided at the pressure relief port 54, and two switches are provided on the pressure relief pipe.

[0044] The present invention provides a piston-type explosion energy test device. The explosion chamber 1 simulates the work done by injecting mixed gas and liquid components into the core 21 (metal support 22 or core 21 placement device 2) under the formation environment pressure. The degree of damage to the core 21 and the explosion potential energy of the explosion energy are expressed, thereby simulating the effect of one or more repeated explosions of the explosive energy on the reservoir in the formation environment.

[0045] The piston chamber 3 and the core 21 placer 2 (piston) convert the energy in the upper explosion chamber 1, which is expressed by the conversion of explosion potential energy into mechanical energy. The shear pin 31 controls whether the entire system is converted into mechanical energy, thereby controlling the force of the explosion potential energy on the core 21. During the entire test process, the device is placed vertically so that the core 21 placer 2 (piston) overcomes the friction force.

[0046] The liquid working chamber and the working observation chamber 5 are connected by pipeline 4646. The liquid working chamber 4 is composed of the upper piston-type inner cavity and the core 21 placer 2 that work on the liquid functional chamber without inserting a pin, so that mechanical energy is converted into liquid compression potential energy. Since the liquid compression energy can be ignored in this device, it is transmitted to the next working observation chamber 5 through the liquid working chamber. The observation window 41 of the liquid working chamber 4 can observe the movement stroke of the core 21 placer 2 (piston) and the equipment status.

[0047] The working observation chamber 5 pushes the piston body 53 in the chamber to move because the pressure in the air chamber 52 is greater than the pressure in the liquid chamber 51. The pressure P1 of the air chamber 52 is greater than P2, which means that the working observation chamber 5 and the liquid working chamber 4 reach energy balance. The corresponding explosion energy value is determined by observing and calibrating the movement value of the piston body 53 in the working observation chamber 5 to form a functional relationship.

[0048] From the above content, it can be seen that the piston-type explosion energy test device of the present invention converts the explosion potential energy into mechanical energy, uses the mechanical energy to do work on the liquid, and uses the pressure of the liquid overflow to do work on the gas to obtain the value of the explosion energy. At the same time, an explosion test is performed on the core 21. Through a series of energy conversions, this device can be equipped with a high-concentration explosion capacity test and is safe.

[0049] The piston-type explosive energy test device and test method are further described below in conjunction with specific embodiments.

[0050] Example 1

[0051] This embodiment provides a method for testing explosive fracturing energy, which tests the effect of an unknown core 21 on an unknown blasting capacity. The test experiment is conducted using the piston-type explosive energy test device of the present invention. The rear cylinder cover 43 of the liquid working chamber 4 is opened, the core 21 placement device 2 is removed, the core 21 and the metal support device are placed in the core 21 placement device 2, and then replaced in the piston chamber 3. The rear cylinder cover 43 is sealed, and the liquid observation chamber and the working observation chamber 5 are closed and connected to the pressure pipeline.

[0052] Inject pressure P1 into the air chamber 52 of the working observation chamber 5, so that the piston body 53 of the working observation chamber 5 is pushed into the bottom, and then inject liquid into the liquid injection port 42 of the liquid working chamber 4 to form a pressure P2, and P1>P2, the pressure inside P2 is sufficient to lift the core 21 placement device 2 (piston) to the predetermined position, inject gas or liquid into the explosion chamber 1, and inject pressure P3 into the explosion chamber 1, so that P1>P2>P3, turn off the switch inside the explosion chamber 1, fix the entire device, and control the concentration. , ignition mode, ignition explosion, the pressure causes the gas in the explosion chamber 1 to explode and release the explosion potential energy, which serves as an explosion test for the core 21. The explosion potential energy works on the liquid in the liquid working chamber 4 through the core 21 placer 2, so that the explosion potential energy is converted into mechanical energy and then works on the liquid again, and the liquid enters the liquid chamber 51 of the work observation chamber 5 through the connecting pipeline 46, and compresses the gas in the equilibrium state to do work, and quantitatively obtains the explosion energy data through the piston body 53 in the work observation chamber 5.

[0053] Example 2

[0054] This embodiment provides a method for testing explosive fracturing energy. The test experiment is carried out by using the piston-type explosive energy test device of the present invention. Under the condition of known explosion temperature and pressure and existing data on the core 21 and the explosion energy, after the test method of Example 1 has been tested under the same conditions, a full-energy explosion test is carried out on the core 21 under the same conditions: the rear cylinder cover 43 of the liquid working chamber 4 is opened, the core 21 placer 2 is withdrawn, the core 21 and the metal support device are placed in the core 21 placer 2, and then placed back into the piston chamber 3. The rear cylinder cover 43 is sealed to close the liquid observation chamber and the working observation chamber 5 are connected to the pressure pipeline. Liquid is injected into the bottom of the liquid working chamber 4, and the liquid pressure is sufficient to make the core 21 placer 2 (Piston) is in place, and the observation stroke is observed through the observation window 41 on the liquid working chamber 4. At this time, a pin is inserted into the pin insertion port to fix the core 21 placer 2 (piston). In this state, the core 21 placer 2 (piston) is a fixed stroke, and the shear force τ1 of the pin is selected to be less than 50% of the stress τ2 of the entire metal component, and its τ1>τ2*50%, ensuring that the overall explosion chamber 1 is still safe after the pin is sheared, and the air cavity 52 in the working observation chamber is injected with pressure P1, and the liquid is injected into the liquid injection port 42 in the liquid working chamber 4 to become pressure P2, so that P1>P2, so that the liquid in the liquid cavity 51 in the working observation chamber 5 is discharged, so that the piston is flexible, and the channel switches in the liquid working chamber 4 and the working observation chamber 5 are opened to ensure the balance of the entire device. At this time, the corresponding mixed gas is injected into the explosion chamber 1 to determine the injection pressure P3 in the explosion chamber 1. The air chamber 52 in the work observation chamber is injected with pressure P1, and the liquid is injected into the liquid injection port 42 in the liquid work chamber 4 to form a pressure P2, so that P1>P2>P3, and the switch in the explosion chamber 1 is turned off. The whole device is fixed, and the explosion is ignited. The pressure causes the gas in the explosion chamber 1 to explode and release the explosion potential energy, which serves as an explosion test for the core 21. The explosion potential energy works on the liquid in the liquid work chamber 4 through the core 21 placer 2, so that the explosion potential energy is converted into mechanical energy and then works on the liquid again, and the liquid enters the liquid chamber 51 of the work observation chamber 5 through the connecting pipeline 46, and compresses the gas in the equilibrium state to do work, and quantitatively obtains the explosion energy data through the piston body 53 in the work observation chamber 5.

[0055] Example 3

[0056] This embodiment provides a method for testing explosive fracturing energy. After the destructive capacity of the explosive energy on the core 21 is known, the ignition and explosion capacity of different gases is further tested. The test experiment is conducted using the piston-type explosive energy test device of the present invention. The rear cylinder cover 43 of the liquid working chamber 4 is opened, and the core 21 placement device 2 is removed. When no core 21 is loaded, only the core 21 placement device 2 is loaded. The corresponding metal liner block is installed in its card slot and placed inside the device cavity. The block is then replaced in the piston chamber 3 and the rear cylinder cover 43 is sealed.

[0057] First, pressure P1 is injected into the air cavity 52 in the working observation chamber to push the piston of the working observation chamber 5 to the bottom. Then, liquid is injected into the liquid injection port 42 in the liquid working chamber 4 to form a pressure P2, and P1>P2. The pressure in P2 is sufficient to lift the core 21 placer 2 to the predetermined position. Gas (liquid) is injected into the explosion chamber 1. By controlling the concentration, ignition, etc., the pressure causes the gas in the cavity to explode and release the explosion potential energy. By observing the working observation chamber 5 and comparing the relationship between the piston movement stroke in the working observation chamber 5 and the indoor temperature and pressure of the explosion chamber 1, the linear relationship of the explosion capacity under different concentrations is obtained.

[0058] Example 4

[0059] This embodiment provides a test method for explosive fracturing energy, which simulates the test situation of injecting gas into the formation and gradually infiltrating the gas into the pores of the formation medium through the pores during the gas injection process, and repeatedly performs explosive fracturing tests on the gas injection continued in a sealed state after one explosion. The test experiment is carried out using the piston-type explosive energy test device of the present invention. The rear cylinder cover 43 is opened, the core 21 placer 2 (piston) is reversed, and the inner and outer wall surfaces of the piston are checked to be smooth and free of debris. The metal support 22 and the core 21 are placed therein, and they are re-installed into the cavity and the core 21 placer 2 (piston) is rotated so that its step surface 45 contacts, and the rear cylinder cover is screwed on. 43. Close the pressure pipeline connecting the liquid observation chamber and the working observation chamber 5, inject liquid into the bottom of the liquid working chamber 4, and its liquid pressure is enough to put the core 21 placer 2 (piston) in place. The observation window 41 on the liquid working chamber 4 is used to observe the stroke. In this state, the core 21 placer 2 (piston) is in a movable state, and the air cavity 52 in the working observation chamber is injected with pressure P1, and the liquid is injected into the liquid injection port 42 in the liquid working chamber 4 to form a pressure P2, so that P1>P2, so that the liquid in the liquid cavity 51 in the working observation chamber 5 is discharged, and the piston is flexible. Open the channel switches in the liquid working chamber 4 and the working observation chamber 5 to ensure the balance of the entire device. At this point, the appropriate mixed gas is injected into the explosion chamber 1, establishing an injection pressure of P3. The pressure in the air chamber 52 of the work observation chamber is then increased to P1, and the liquid is injected into the liquid work chamber 4 through the liquid injection port 42, reaching a pressure of P2, such that P1>P2>P3. The switch in the explosion chamber 1 is turned off, the entire device is secured, and the explosion is ignited. After the explosion, the core 21 placement device 2 (piston) is not removed. The pressure connecting the liquid work chamber 4 and the work observation chamber 5 is closed, and the pressure in the liquid work chamber 4 is re-pressurized to P22. The core 21 placement device 2 (piston) is then pushed back into its initial position. The pressure in the explosion chamber 1 is now P11. The pressure in the liquid chamber 51 of the work observation chamber 5 is relieved, and the pressure in the air chamber 52 is re-pressurized to P33, thus achieving P11>P22>P33. The pressure connecting the liquid work chamber 4 and the work observation chamber 5 is then opened to return the device to equilibrium. Ignition is then initiated and the explosion test continues. This process can be repeated.

[0060] In summary, the present invention provides a piston-type explosion energy test device and an explosion fracturing energy test method. The explosion chamber simulates the effect of one or more repeated explosions of explosive energy on the reservoir in the formation environment. The piston chamber converts the energy in the upper explosion chamber from the explosion potential energy into mechanical energy. The liquid working chamber converts the mechanical energy into the liquid compression potential energy. Since the liquid compression energy can be ignored in this device, it is transmitted to the next working observation chamber through the liquid working. The observation window of the liquid working chamber can observe the movement stroke of the core placer (piston) and the equipment status. Through a series of energy conversions, the test device of the present invention can have a higher concentration explosion capacity test and is safe.

[0061] The explosive fracturing energy test method is divided into two specific methods: core placement and non-core placement. The purpose is to obtain a dynamic parameter of the explosive energy at different concentrations after the core's explosive effect in the gas has been determined. Furthermore, without the use of cores, test parameters can be obtained under different pressures and concentration ratios. The gas concentration can be pre-calculated and set in this test device. Explosion tests are then conducted under simulated formation conditions, simulating the injection pressure and concentration. This allows for testing the effects of explosions on rock in various environments while also meeting safety requirements during the test.

[0062] The technical features of the above-mentioned embodiments can be combined arbitrarily. In order to make the description concise, not all possible combinations of the technical features in the above-mentioned embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0063] The above-described embodiments merely illustrate several implementations of the present invention, and while their descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the patent. It should be noted that a person skilled in the art would be able to make numerous variations and improvements without departing from the spirit of the present invention, all of which fall within the scope of protection of the present invention. Therefore, the scope of protection of the patent for this invention shall be determined by the appended claims.

Claims

1. A piston-type explosive energy test device, characterized in that: The utility model comprises a main body, which is provided with an explosion chamber, a piston chamber and a liquid working chamber connected from top to bottom in sequence. A rear cylinder cover is provided at the bottom of the liquid working chamber, and the rear cylinder cover is sealed with the main body. An igniter is provided on the top of the explosion chamber. A gas injection port is provided on one side of the explosion chamber, and a gas injection pipe is provided at the gas injection port. The gas injection pipe is connected with the explosion chamber, and a first switch and an injection-type one-flow valve are provided on the gas injection pipe. A core placer is provided in the piston chamber, and the core placer forms a piston structure with the piston chamber. A shear pin corresponding to the bottom of the piston chamber is provided on the main body. A liquid injection port and a liquid discharge port are respectively provided at the bottom of the liquid working chamber, and a working observation chamber is connected to the liquid discharge port through a pipeline.

2. A piston-type explosive energy test device according to claim 1, characterized in that: A pressure gauge and a thermometer are also provided on the top of the explosion chamber.

3. A piston-type explosive energy test device according to claim 1, characterized in that: A liquid injection pipe is provided at the liquid injection port, a second switch is provided on the liquid injection pipe, and an observation window is provided at the liquid working chamber.

4. A piston-type explosive energy test device according to claim 1, characterized in that: The liquid injection port and the liquid discharge port are respectively arranged on both sides of the liquid working chamber. A pressure gauge is also arranged below the liquid discharge port. A check valve and a third switch are arranged on the pipeline connected to the liquid discharge port.

5. The piston-type explosive energy test device according to claim 1, characterized in that: The work observation chamber includes two upper and lower cavities, which are separated by a piston body. The cavity located below the piston body and connected to the liquid work chamber is a liquid cavity, and a pressure relief port is provided at the bottom of the liquid cavity. The cavity located above the piston body is an air cavity, and an air injection port is provided.

6. The piston-type explosive energy test device according to claim 5, characterized in that: A pressure gauge and a safety valve are provided on the top of the air cavity, an air injection pipe communicating with the air cavity is provided at the air injection port, a fourth switch is provided on the air injection pipe, a pressure relief pipe communicating with the liquid cavity is provided at the pressure relief port, and a fifth switch is provided on the pressure relief pipe.

7. A method for testing explosive fracturing energy, using the piston-type explosive energy testing device according to any one of claims 1 to 6 for testing, characterized in that: The method includes two methods: placing a core and not placing a core. The first method is to place a core in a core placer, and conduct explosion tests on the core by exploding gases of different concentrations in the explosion chamber and releasing the explosion potential energy, thereby obtaining explosion energy data under different gas concentrations. The second method is to only place a core placer without placing a core, and conduct explosions of gases of different concentrations in the explosion chamber and release the explosion potential energy, thereby comparing the relationship between the piston movement stroke in the work observation chamber and the temperature and pressure in the explosion chamber, thereby obtaining a linear relationship between the explosion capacity under different concentrations.

8. The explosive fracturing energy testing method according to claim 7, characterized in that: The steps include: S1. Open the rear cylinder cover of the liquid working chamber, remove the core placing device, place the core and the metal support device in the core placing device, replace them in the piston chamber, and seal the rear cylinder cover; S2. Inject pressure P1 into the air cavity of the working observation cavity so that the piston body of the working observation cavity is pushed into the bottom, and inject liquid into the liquid injection port of the liquid working cavity to form pressure P2, and P1>P2. The pressure in P2 is sufficient to lift the core placer to the predetermined position, and inject gas or liquid into the explosion cavity. By controlling the concentration and ignition method, the pressure causes the gas in the explosion cavity to explode and release the explosion potential energy, which serves as an explosion test for the core. The explosion potential energy works on the liquid in the liquid working cavity through the core placer, so that the explosion potential energy is converted into mechanical energy and then works on the liquid again. The liquid is allowed to enter the liquid cavity of the working observation cavity through the connecting pipeline, and the gas in the equilibrium state is compressed and worked. The explosion energy data is quantitatively obtained through the piston body in the working observation cavity.

9. The explosive fracturing energy testing method according to claim 7, characterized in that: The steps include: S1. Open the rear cylinder cover of the liquid working chamber, remove the core placer, place the core and the metal support device in the core placer, re-insert it into the piston chamber, and seal the rear cylinder cover; S2. Inject pressure P1 into the air cavity in the working observation chamber so that the piston of the working observation chamber is pushed to the bottom, and inject liquid into the liquid working chamber injection port to form pressure P2, and P1>P2. The pressure in P2 is enough to lift the core placer to the predetermined position, and insert shear pins into the entire cavity body and the internal core placer. The shear force τ1 of the pins is less than 50% of the stress τ2 of the entire metal component, and τ1>τ2*50%. The liquid in the liquid cavity of the working observation chamber is discharged, the piston is flexible, and the channel switch in the liquid working chamber and the working observation chamber is opened to ensure the balance of the entire device. At this time, the corresponding mixed gas is injected into the explosion chamber to determine the injection pressure P3 in the explosion chamber, the gas cavity in the work observation chamber is injected with pressure P1, and the liquid is injected into the liquid injection port in the liquid work chamber to make it pressure P2, so that P1>P2>P3, the switch in the explosion chamber is turned off, the whole device is fixed, and the explosion is ignited. The pressure causes the gas in the explosion chamber to explode and release the explosion potential energy, which serves as an explosion test for the core. The explosion potential energy works on the liquid in the liquid work chamber through the core placer, so that the explosion potential energy is converted into mechanical energy and then works on the liquid again, and the liquid enters the liquid cavity of the work observation chamber through the connecting pipeline, and compresses the gas in the equilibrium state to do work, and the explosion energy data is quantitatively obtained through the piston body in the work observation chamber.

10. The explosive fracturing energy testing method according to claim 7, characterized in that: The steps include: S1. Open the rear cylinder cover of the liquid working chamber, remove the core loader, and install the core loader without the core in the core loader. Place the corresponding metal liner block in its slot and place it inside the device cavity. Put it back into the piston cavity and seal the rear cylinder cover. S2. Inject pressure P1 into the air cavity in the working observation chamber so that the piston of the working observation chamber is pushed to the bottom. Inject liquid into the liquid filling port of the liquid working chamber to form a pressure P2, and P1>P2. The pressure in P2 is sufficient to lift the core placer to the predetermined position. Inject gas into the explosion chamber. By controlling the concentration, ignition, etc., the pressure causes the gas in the cavity to explode and release the explosion potential energy. By observing the working observation chamber and comparing the relationship between the piston movement stroke in the working observation chamber and the temperature and pressure in the explosion chamber, the linear relationship of the explosion capacity under different concentrations is obtained.

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