Shearing self-supporting crack slurry pollution experimental device and method

Abstract

The invention discloses a shear self-supporting crack mud pollution experiment device and method, and belongs to the technical field of rock displacement experiments. A clamp holder and an intermediate container are arranged for simulating the invasion condition of mud in a shear self-supporting crack; a clamp holder, an intermediate container, a measuring cylinder, a high-pressure gas storage tank and a confining pressure pump are adopted to simulate the whole process of shearing self-supporting crack pollution, blowout and liquid reinjection of the heavy mud pollution repeated transformation well. The device is simple to operate and is tightly combined with the working condition of the slurry-polluted well. The experimental device is simple in structure and convenient to operate, and rock parameters can be rapidly measured on site; slurry pollution research on the shear self-supporting crack is developed, and the mechanism and rule of pollution of the slurry to the shear self-supporting crack are broken through an innovative experimental device and method, so that support is provided for transformation of wells of the type.

Description

Technical Field

[0001] The invention belongs to the technical field of rock displacement experiments, and in particular relates to a shear self-supporting fracture mud pollution experimental device and method. Background Art

[0002] The investigation shows that mud clay will invade the formation pores and natural fractures to varying degrees, especially for high-yield carbonate oil layers. The degree of invasion is related to drilling time, formation permeability, mud type, and the number of trips during drilling operations. Mud filtrate can also cause clay expansion and migration. HCO3- ions in formation water may also form precipitation with Ca2+ ions in high-calcium mud and block near the wellbore. The existing reported patents and papers mainly study the pollution and invasion of mud into natural fractures under drilling conditions, and mainly consider the invasion process of mud under in-situ conditions or drilling conditions. In the pollution of natural fractures, the shear dislocation of natural fractures and the process of mud invasion, blowout and re-injection are not considered. For repeated transformation wells with heavy mud pollution, the underground natural fractures are subjected to stress disturbance and shear dislocation after the initial transformation. It is not clear how the mud invades in the self-support of shear dislocation, whether it can be blown out to unblock, and whether the mud affects the subsequent fracturing construction pressure. There is a lack of testing equipment and testing methods. Summary of the invention

[0003] In order to overcome the shortcomings of the above-mentioned prior art, the purpose of the present invention is to provide a shear self-supporting fracture mud contamination experimental device and method to solve the technical problems that the simulation research in the prior art does not take into account the shear dislocation of natural fractures and the mud invasion, blowout and re-injection process, how the mud invades in the shear dislocation self-support, whether it can be blown out to unblock, whether the mud affects the subsequent fracturing construction pressure, etc., and there is a lack of testing devices and testing methods.

[0004] In order to achieve the above object, the present invention adopts the following technical solutions:

[0005] A shear self-supporting fracture mud pollution experimental device comprises: a clamp, the inlet end of the clamp is connected to an intermediate container, the intermediate container is connected to a high-pressure gas storage tank, and a pressure gauge is arranged between the two, the outlet end of the clamp is connected to a measuring cylinder, a core is placed inside the clamp, and a confining pressure pump is connected.

[0006] Preferably, a circulation device is also provided between the intermediate container and the inlet end of the holder.

[0007] Preferably, the circulation device comprises a shell, the inside of the shell is connected to the pressure providing device via an air inlet pipe, a valve is arranged on the air inlet pipe, and an outlet is arranged on the shell.

[0008] Preferably, a six-way valve is connected to the intermediate container between the clamp and the high-pressure gas storage tank.

[0009] Preferably, the core is a fractured core.

[0010] The present invention also discloses a shear self-supporting fracture mud contamination test method, which uses any of the above-mentioned experimental devices to conduct the test, and specifically includes the following steps:

[0011] Placing the slurry in an intermediate container and connecting the inlet end of the holder to the intermediate container;

[0012] Adjust the high-pressure gas storage tank so that the pressure gauge reading reaches the set value and record the start time;

[0013] When no more liquid flows out of the holder outlet, record the amount of liquid in the measuring cylinder and the end time;

[0014] Turn off the gas source, remove the pressure at the inlet end of the holder and calculate the intrusion permeability;

[0015] Replace the inlet and outlet ends of the clamp, repeat the above steps to simulate reverse flow and end the experiment.

[0016] Preferably, the intrusion permeability is calculated based on the start time, the end time, the liquid output and the pressure gauge reading.

[0017] Preferably, the calculation method of the intrusion permeability is as follows:

[0018]

[0019] Where: Δp is the pressure difference before and after the fluid passes through the core, Q is the flow rate through the sand body under the action of the pressure difference, μ is the viscosity of the fluid passing through the core, L is the length of the core, and A is the cross-sectional area of ​​the core perpendicular to the flow direction.

[0020] Preferably, after the inlet and outlet ends of the clamp are replaced, when simulating reverse discharge, a six-way valve is used to replace the intermediate container, which specifically includes the following steps:

[0021] The inlet and outlet ends of the holder are swapped, and the holder, six-way valve and high-pressure gas storage tank are connected in sequence, and the other end of the holder is connected to the measuring cylinder;

[0022] Adjust the high-pressure gas storage tank so that the pressure gauge reading reaches the set value and record the start time;

[0023] When no more liquid flows out from one end of the measuring cylinder, record the amount of liquid flowing out and the end time; close the high-pressure gas storage tank and calculate the reverse permeability.

[0024] Preferably, the reverse permeability is calculated based on the start time, end time, liquid output and pressure gauge reading after the inlet and outlet ends of the holder are replaced.

[0025] Compared with the prior art, the present invention has the following beneficial effects:

[0026] The present invention discloses a mud pollution experimental device for shear self-supporting fractures, wherein a clamp and an intermediate container are provided for simulating the intrusion of mud into shear self-supporting fractures, and the clamp, the intermediate container, the measuring cylinder, the high-pressure gas storage tank and the confining pressure pump are used to realize the simulation of the whole process of shear self-supporting fracture pollution-blowing-reinjection of heavy mud-contaminated repeated transformation wells. The device is easy to operate and is closely integrated with the working conditions of mud-contaminated wells. The experimental device of the present invention has a simple structure and is easy to operate, and can quickly realize the determination of rock parameters on site; the mud pollution research of shear self-supporting fractures is carried out, and the mechanism and law of mud pollution on shear self-supporting fractures are broken through by innovating experimental devices and methods, providing support for the transformation of such wells.

[0027] Furthermore, a six-way valve is used to replace the intermediate container to simulate the backflow of mud in the shear self-supporting fracture, which is conducive to the simulation of the entire process of shear self-supporting fracture pollution-blowing-reinjection in the wells repeatedly transformed by heavy mud pollution.

[0028] The experimental method of the present invention is easy to operate, closely combined with the working conditions of mud-contaminated wells, and can relatively simply obtain the permeability. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 This is a schematic diagram of the structure of the intrusion situation of the experimental device of the present invention;

[0030] Figure 2 This is a schematic diagram of the flowback structure of the experimental device of the present invention;

[0031] Figure 3 It is a schematic diagram of the principle of the circulation device in the experimental device of the present invention;

[0032] Figure 4 It is a schematic diagram of permeability change under different conditions of the present invention;

[0033] Figure 5 It is a flow chart of the experimental method of the present invention;

[0034] Figure 6 The figure is a flow chart of the experimental method of the embodiment of the present invention.

[0035] Among them: 1- measuring cylinder; 2- core; 3- holder; 4- confining pressure pump; 5- circulation device; 6- pressure gauge; 71- intermediate container; 72- six-way valve; 8- high-pressure gas storage tank. DETAILED DESCRIPTION

[0036] In order to enable those skilled in the art to better understand the scheme of the present invention, the technical scheme in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present invention.

[0037] It should be noted that the terms "first", "second", etc. in the specification and claims of the present invention and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the data used in this way can be interchanged where appropriate, so that the embodiments of the present invention described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units that are clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0038] The present invention is further described in detail below in conjunction with the accompanying drawings:

[0039] See also Figure 1 A shear self-supporting fracture mud pollution experimental device includes a core 2 arranged in a clamp 3; a confining pressure pump 4 for providing the required pressure to the core 2; the inlet end of the clamp 3 is connected to an intermediate container 71, and the outlet end is connected to a measuring cylinder 1; the intermediate container 71 is connected to a pressure gauge 6, and a high-pressure gas storage tank 8 for providing nitrogen is also included; the inlet end of the clamp 3 is connected to the intermediate container 71, the intermediate container 71 is connected to the high-pressure gas storage tank 8, and a pressure gauge 6 is also arranged between the two, the outlet end of the clamp 3 is connected to a measuring cylinder 1, the clamp 3 contains a core 2 inside, and is also connected to a confining pressure pump 4. The clamp 3 and the intermediate container 71 are set to simulate the intrusion of mud in the shear self-supporting fracture, and the clamp 3, the intermediate container 71, the measuring cylinder 1, the high-pressure gas storage tank 8 and the confining pressure pump 4 are used to realize the simulation of the whole process of shear self-supporting fracture pollution-spraying-reinjection of heavy mud pollution repeated transformation wells. The device is easy to operate and is closely integrated with the working conditions of mud pollution wells. The experimental device of the present invention has a simple structure and is easy to operate, and can quickly measure rock parameters on site; the mud contamination of shear self-supporting fractures is studied, and the mechanism and law of mud contamination of shear self-supporting fractures are analyzed through innovative experimental devices and methods, providing support for the transformation of such wells.

[0040] Furthermore, a circulation device 5 is provided at the inlet end of the holder 3 for circulating the mud on the end surface of the core 2 during the experiment.

[0041] Furthermore, the core 2 is a fractured core 2.

[0042] See also Figure 2 A shear self-supporting fracture mud pollution experimental device includes a core 2 arranged in a clamp 3; a confining pressure pump 4 for providing the required pressure to the core 2; the inlet and outlet ends of the clamp 3 are exchanged, and the original outlet end replaces the intermediate container 71 and is connected to the six-way valve 72; the other end is connected to the measuring cylinder 1, and the six-way valve 72 is connected to the pressure gauge 6, and also includes a high-pressure gas storage tank 8 for providing nitrogen; the new inlet end of the clamp 3 is connected to the six-way valve 72, and the six-way valve 72 is connected to the high-pressure gas storage tank 8, and a pressure gauge 6 is also arranged between the two, and the new outlet end of the clamp 3 is connected to the measuring cylinder 1, and the core 2 is placed inside the clamp 3, and is also connected to the confining pressure pump 4. The six-way valve 72 is used to replace the intermediate container 71 to simulate the backflow of mud in the shear self-supporting fracture, which is conducive to the simulation of the whole process of shear self-supporting fracture pollution-blowing-reinjection in the repeated transformation well of heavy mud pollution.

[0043] In some embodiments, the inlet end of the holder 3 is provided with a circulation device 5 for circulating mud on the end surface of the core 2 during the experiment.

[0044] See also Figure 3 The circulation device 5 includes a shell 9, and the shell 9 is connected to the pressure providing device through an air inlet pipe 10. The air inlet pipe 10 is provided with a valve 11, and the shell 9 is provided with an outlet 12.

[0045] The present invention also discloses a shear self-supporting fracture mud contamination test method, which specifically comprises the following steps:

[0046] S1: placing the slurry in the intermediate container 71 and connecting the inlet end of the holder 3 to the intermediate container 71;

[0047] S2: Adjust the high-pressure gas storage tank 8 so that the pressure gauge 6 reading reaches the set value and record the start time;

[0048] S3: When no more liquid flows out from the outlet of the holder 3, the amount of liquid discharged from the measuring cylinder 1 is recorded and the end time is recorded;

[0049] S4: Turn off the gas source, remove the pressure at the inlet end of the holder 3 and calculate the intrusion permeability;

[0050] S5: Replace the inlet and outlet ends of the clamp 3, repeat the above steps to simulate the reverse flow and end the experiment.

[0051] The experimental method of the present invention is easy to operate, closely combined with the working conditions of mud-contaminated wells, and can obtain permeability relatively simply. It is used to simulate the intrusion and backflow of mud in shear self-supporting fractures. The clamp 3, intermediate container 71, measuring cylinder 1, high-pressure gas storage tank 8 and confining pressure pump 4 are used to realize the simulation of the whole process of shear self-supporting fracture pollution-release-reinjection of heavy mud-contaminated repeated transformation wells. The device is easy to operate and closely combined with the working conditions of mud-contaminated wells. The experimental device of the present invention has a simple structure and is easy to operate. It can quickly realize the determination of rock parameters on site; carry out research on mud pollution of shear self-supporting fractures, and through innovative experimental devices and methods, break the mechanism and law of mud pollution on shear self-supporting fractures, and provide support for the transformation of such wells.

[0052] In some embodiments, the intrusion permeability is calculated based on the start time, the end time, the liquid output, and the pressure gauge reading.

[0053] Preferably, the calculation method of the intrusion permeability is as follows:

[0054]

[0055] Where: Δp is the pressure difference before and after the fluid passes through the core, Q is the flow rate through the sand body under the action of the pressure difference, μ is the viscosity of the fluid passing through the core, L is the length of the core, and A is the cross-sectional area of ​​the core perpendicular to the flow direction.

[0056] Preferably, the Δp is the pressure gauge reading minus standard atmospheric pressure.

[0057] In some embodiments, after replacing the inlet and outlet ends of the clamp 3, the six-way valve 72 is used to replace the intermediate container 71 to simulate the backflow of mud in the shear self-supporting fracture, which is conducive to the simulation of the whole process of shear self-supporting fracture pollution-blowing-reinjection in the repeated transformation well of heavy mud pollution. Specifically, the following steps are included:

[0058] S6: The inlet and outlet ends of the holder 3 are swapped, the holder 3, the six-way valve 72 and the high-pressure gas storage tank 8 are connected in sequence, and the other end of the holder 3 is connected to the measuring cylinder 1;

[0059] S7: Adjust the high-pressure gas storage tank 8 so that the pressure gauge 6 reading reaches the set value, and record the start time;

[0060] S8: When no more liquid flows out from one end of the measuring cylinder 1, record the liquid output and the end time; close the high-pressure gas storage tank 8 and calculate the reverse permeability.

[0061] In some embodiments, the reverse permeability is calculated based on the start time, end time, liquid output and pressure gauge reading after the inlet and outlet ends of the holder 3 are replaced.

[0062] In some embodiments, after the experiment is completed, the pressure at the inlet end of the holder 3 is released, the pipeline is disassembled, the holder 3 and the core 2 are removed and cleaned; the measuring cylinder 1 is removed and cleaned.

[0063] [Example 1]

[0064] A shear self-supporting fracture mud pollution experimental device, characterized in that it includes: a clamp 3, the inlet end of the clamp 3 is connected to an intermediate container 71, the intermediate container 71 is connected to a high-pressure gas storage tank 8, and a pressure gauge 6 is also arranged between the two, the outlet end of the clamp 3 is connected to a measuring cylinder 1, a core 2 is placed inside the clamp 3, and a confining pressure pump 4 is also connected.

[0065] An experimental method for a shear self-supporting fracture mud contamination experimental device, see Figure 5 , including the following steps:

[0066] S1: placing the slurry in the intermediate container 71 and connecting the inlet end of the holder 3 to the intermediate container 71;

[0067] S2: Adjust the high-pressure gas storage tank 8 so that the pressure gauge 6 reading reaches the set value and record the start time;

[0068] S3: When no more liquid flows out from the outlet of the holder 3, the amount of liquid discharged from the measuring cylinder 1 is recorded and the end time is recorded;

[0069] S4: Turn off the gas source, remove the pressure at the inlet end of the holder 3 and calculate the intrusion permeability;

[0070] S5: Replace the inlet and outlet ends of the clamp 3, repeat the above steps to simulate the reverse flow and end the experiment.

[0071] The intrusion permeability is calculated based on the start time, end time, liquid output and pressure gauge reading; the calculation method of the intrusion permeability is as follows:

[0072]

[0073] Where: Δp is the pressure difference before and after the fluid passes through the core, Q is the flow rate through the sand body under the action of the pressure difference, μ is the viscosity of the fluid passing through the core, L is the length of the core, and A is the cross-sectional area of ​​the core perpendicular to the flow direction.

[0074] The Δp is the pressure gauge reading minus the standard atmospheric pressure.

[0075] [Example 2]

[0076] like Figure 1 and Figure 2As shown, a shear self-supporting fracture mud pollution experimental device includes a core 2 arranged in a clamp 3; it also includes a confining pressure pump 4 for providing the required pressure into the core 2; the inlet end of the clamp 3 is connected to an intermediate container 71 or a six-way valve 72, and the outlet end is connected to a measuring cylinder 1; the intermediate container 71 or the six-way valve 72 is connected to a pressure gauge 6, and it also includes a high-pressure gas storage tank 8 for providing nitrogen. The inlet end of the clamp 3 is provided with a circulation device 5 for circulating mud on the end face of the core 2 during the experiment. The core 2 is a fractured core. The principle of the circulation device 5 is as follows Figure 3 As shown, any device that can achieve the above functions can be used. Figure 3 As shown, the circulation device comprises a housing, the housing is connected to a pressure providing device through an air inlet pipe, and a valve is arranged on the air inlet pipe. An outlet is arranged on the housing.

[0077] An experimental method for a shear self-supporting fracture mud contamination experimental device, see Figure 6 , including the following steps:

[0078] S1: placing the slurry in the intermediate container 71 and connecting the inlet end of the holder 3 to the intermediate container 71;

[0079] S2: Adjust the high-pressure gas storage tank 8 so that the pressure gauge 6 reading reaches the set value and record the start time;

[0080] S3: When no more liquid flows out from the outlet of the holder 3, the amount of liquid discharged from the measuring cylinder 1 is recorded and the end time is recorded;

[0081] S4: Turn off the gas source, remove the pressure at the inlet end of the holder 3 and calculate the intrusion permeability;

[0082] S5: Replace the inlet and outlet ends of the holder 3; use the six-way valve 72 to replace the intermediate container 71, the holder 3, the six-way valve 72 and the high-pressure gas storage tank 8 are connected in sequence, and the other end of the holder 3 is connected to the measuring cylinder 1;

[0083] S6: Adjust the high-pressure gas storage tank 8 so that the pressure gauge 6 reading reaches the set value and record the start time;

[0084] S7: When no more liquid flows out from one end of the measuring cylinder 1, record the liquid output and the end time; close the high-pressure gas storage tank 8 and calculate the reverse permeability.

[0085] The intrusion permeability is calculated based on the start time, end time, liquid output and pressure gauge reading; the permeability test is carried out according to Darcy's law. When water passes through the core, the size of its flow rate Q is proportional to the cross-sectional area of ​​the core and the inlet and outlet pressure difference, and inversely proportional to the length of the core.

[0086] The calculation method of intrusion permeability is as follows:

[0087]

[0088] Where: Δp is the pressure difference before and after the fluid passes through the core, Q is the flow rate through the sand body under the action of the pressure difference, μ is the viscosity of the fluid passing through the core, L is the length of the core, and A is the cross-sectional area of ​​the core perpendicular to the flow direction.

[0089] The Δp is the pressure gauge reading minus the standard atmospheric pressure.

[0090] The reverse permeability is calculated based on the start time, end time, liquid output and pressure gauge reading after the inlet and outlet ends of the holder 3 are replaced.

[0091] During the experiment, 24 groups of experiments were conducted according to the above method and the parameter conditions in Table 1.

[0092] Table 1. Experimental parameters and conditions

[0093]

[0094]

[0095] By comparing the core photos after mud contamination and the calculated permeability values, the results are as follows Figure 4 As shown in Table 2, Figure 4 It can be seen from Table 2 that mud has a certain degree of damage to the permeability of shear dislocation natural fractures. The liquid permeability of the core before and after mud contamination decreases by 10% to 20%. With the increase of confining pressure, the damage does not show a clear change pattern, because after the fracture is dislocated, the surface roughness of each group of experimental fractures is different.

[0096] Table 2. Permeability of self-supporting fractures before and after mud contamination

[0097] Experimental conditions Permeability before mud pollution / mD Permeability after mud contamination / mD Low density mud + confining pressure 5MPa 39.85969 31.78842 Low density mud + confining pressure 7MPa 105.3053 104.9803 Low density mud + confining pressure 9MPa 106.2925 93.78752 High density mud + confining pressure 5MPa 53.59286 53.35746 High density mud + confining pressure 7MPa 49.15261 39.48948 High density mud + confining pressure 9MPa 0.01155 0.008529

[0098] The experimental device of the present invention has a simple structure and is easy to operate, and can quickly measure rock parameters on site; the experimental method can relatively simply obtain permeability.

[0099] The above contents are only for explaining the technical idea of ​​the present invention and cannot be used to limit the protection scope of the present invention. Any changes made on the basis of the technical solution in accordance with the technical idea proposed by the present invention shall fall within the protection scope of the claims of the present invention.

Claims

1. A shear self-supporting fracture mud pollution experimental device, characterized in that: include: The inlet end of the clamp (3) is connected to an intermediate container (71), the intermediate container (71) is connected to a high-pressure gas storage tank (8), and a pressure gauge (6) is arranged between the two. The outlet end of the clamp (3) is connected to a measuring cylinder (1), a core (2) is placed inside the clamp (3), and the clamp (3) is also connected to a confining pressure pump (4).

2. A shear self-supporting fracture mud pollution experimental device according to claim 1, characterized in that: A circulation device (5) is also provided between the intermediate container (71) and the inlet end of the holder (3).

3. A shear self-supporting fracture mud pollution experimental device according to claim 2, characterized in that: The circulation device (5) comprises a shell (9), the shell (9) is connected to a pressure providing device via an air inlet pipe (10), a valve (11) is provided on the air inlet pipe (10), and an outlet (12) is provided on the shell (9).

4. A shear self-supporting fracture mud pollution experimental device according to claim 1, characterized in that: A six-way valve (72) is connected to the intermediate container (71) between the clamp (3) and the high-pressure gas storage tank (8).

5. A shear self-supporting fracture mud pollution experimental device according to claim 1, characterized in that: The core (2) is a fractured core.

6. A shear self-supporting fracture mud contamination test method, characterized in that: The experiment is carried out using the experimental device described in any one of claims 1 to 5, which specifically includes the following steps: Placing the slurry in an intermediate container (71) and connecting the inlet end of the holder (3) to the intermediate container (71); Adjust the high-pressure gas storage tank (8) so that the pressure gauge (6) reading reaches the set value, and record the start time; When no more liquid flows out of the outlet of the holder (3), the amount of liquid flowing out of the measuring cylinder (1) is recorded, and the end time is recorded; Turn off the gas source, release the pressure at the inlet end of the holder (3) and calculate the intrusion permeability; Replace the inlet and outlet ends of the clamp (3), repeat the above steps to simulate reverse discharge and end the experiment.

7. A shear self-supporting fracture mud contamination test method according to claim 6, characterized in that: The intrusion permeability is calculated based on the start time, end time, liquid output and pressure gauge reading.

8. A shear self-supporting fracture mud contamination test method according to claim 7, characterized in that: The calculation method of the intrusion permeability is as follows: Where: Δp is the pressure difference before and after the fluid passes through the core, Q is the flow rate through the core under the action of the pressure difference, μ is the viscosity of the fluid passing through the core, L is the length of the core, and A is the cross-sectional area of ​​the core perpendicular to the flow direction.

9. A shear self-supporting fracture mud contamination test method according to claim 6, characterized in that: After the inlet and outlet ends of the clamp (3) are replaced, when simulating reverse discharge, the six-way valve (72) is used to replace the intermediate container (71), which specifically includes the following steps: The inlet and outlet ends of the holder (3) are swapped, the holder (3), the six-way valve (72) and the high-pressure gas storage tank (8) are connected in sequence, and the other end of the holder (3) is connected to the measuring cylinder (1); Adjust the high-pressure gas storage tank (8) so that the pressure gauge (6) reading reaches the set value, and record the start time; When no more liquid flows out from one end of the measuring cylinder (1), the liquid output and the end time are recorded; the high-pressure gas storage tank (8) is closed, and the reverse permeability is calculated.

10. A shear self-supporting fracture mud contamination test method according to claim 6, characterized in that: The reverse permeability is calculated based on the start time, end time, liquid output and pressure gauge reading after the inlet and outlet ends of the holder (3) are replaced.

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