Device and method for synchronously testing sealing performance of first interface and second interface of well cementation

Abstract

The invention provides a device and a method for synchronously testing sealing performance of a first interface and a second interface of well cementation, and belongs to the field of oil-gas well engineering technology research. The device comprises a three-axis chamber, wherein an upper pressing head and a lower pressing head are arranged in the three-axis chamber; the combined sample is arranged between the upper pressure head and the lower pressure head, and two sets of pore channel systems are arranged on the combined sample; and the two groups of test pipelines are respectively communicated with the two sets of duct systems on the combined sample. The sealing performance of the first interface and the second interface of well cementation can be synchronously tested, the two interfaces can be synchronously tested under the high-temperature complex load condition, and the device and the method can be closer to the real environment of a deep stratum.

Description

Technical Field

[0001] The invention belongs to the research field of oil and gas well engineering technology, and in particular relates to a device and method for synchronously testing the sealing performance of the first and second interfaces of cementing. Background Art

[0002] Cementing is a very important link and means in the process of drilling and completing oil and gas wells. When the drill bit reaches a certain depth, it is necessary to pull the drill bit out of the well, lower a hollow steel pipe called casing into the well, and then inject cement slurry (a mixture of dry cement, water and admixtures) into the annular space between the wellbore and the casing and let it solidify. This process is called cementing. Then use a drill bit with a smaller diameter to continue drilling. Depending on the complexity of the formation being drilled, a well needs to go through one to several such processes before it can reach the target oil and gas layer.

[0003] The purpose of cementing is to isolate the formation, reinforce the wellbore, and establish a well-sealed flow channel in the well to ensure continued safe drilling and normal subsequent operations and production. Cementing is an important part of the oil and gas well construction process. The quality of cementing is not only related to the speed and cost of drilling, but also affects whether the oil and gas well can be produced smoothly in the future, the life of the oil and gas well, and even the recovery rate of the oil and gas reservoir.

[0004] The cement sheath is an annular cement stone structure formed between the casing and the formation after cementing construction. The bonding surface between the cement sheath and the casing is called the first cementing interface, and the composite bonding surface formed by the cement sheath and the surrounding rock of the well wall is called the second cementing interface. Interface bonding has always been considered the weak link of the overall structure. The root cause of the current quality problems of oil and gas well cementing is mostly the failure of the cementing interface sealing system. Under the action of high temperature and high pressure environment and complex loads in the well, the cementing interface is more prone to interface bonding damage than the cement sheath body, resulting in the channeling of downhole fluids (oil, gas, water) along the interface, and the cement sheath loses its sealing effect. Therefore, the sealing test and evaluation of the first and second cementing interfaces are crucial, especially the sealing test under high temperature, high pressure and complex loads.

[0005] In the existing literature on cementing interface sealing test, steel pipe-cement ring-steel pipe and steel pipe-cement ring-rock composite specimens are mainly designed. The composite specimens are cylindrical or annular. This type of sample has four main defects: first, it is more difficult and difficult to control to make a bumpy and rough surface on the side of the cylinder; second, further pouring cement slurry on the surface of such a cylinder will lead to interface variability due to gravity and surface curvature, that is, it may lead to a situation where the local cement slurry density is larger and the bonding is better, and the local cement slurry density is smaller and the bonding is worse. The test results of the prepared specimens will show a large discreteness, and it is not easy to obtain a relatively accurate law; third, the formed interface is annular, and only 1 to 2 pairs of monitoring points are arranged on both sides of the annular interface. It is not easy to monitor the sealing of the entire annular interface, and the rupture of the cement ring body will also interfere with the monitoring effect of the interface monitoring point; fourth, only relatively simple working conditions can be used for sealing tests, and real-time synchronous monitoring of the sealing of the first and second cementing interfaces under high temperature, high pressure and complex load conditions cannot be achieved. Summary of the invention

[0006] The purpose of the present invention is to solve the above-mentioned problems existing in the prior art and to provide a device and method for synchronously testing the sealing performance of the first and second interfaces of cementing.

[0007] The present invention is achieved through the following technical solutions:

[0008] A first aspect of the present invention provides a device for synchronously testing the sealing performance of the first and second interfaces of cementing, comprising:

[0009] A three-axis chamber, wherein an upper pressure head and a lower pressure head are arranged in the three-axis chamber;

[0010] A combined sample is arranged between the upper pressure head and the lower pressure head, and the combined sample is provided with two sets of channel systems;

[0011] Two groups of test pipelines are respectively connected with two sets of channel systems on the combined sample.

[0012] A further improvement of the present invention is:

[0013] The combined sample is a steel block-cement stone-shale combined sample, which includes a steel block, cement stone and shale arranged in sequence from top to bottom. The interface between the steel block and the cement stone is used to simulate the first cementing interface, and the interface between the cement stone and the shale is used to simulate the second cementing interface.

[0014] A further improvement of the present invention is:

[0015] The steel block is a cylindrical structure, and a first hole and a second hole are provided through the steel block, and the central axes of the first hole and the second hole are parallel to the central axis of the steel block;

[0016] Thin steel tubes are placed in the first channel and the second channel, and the gaps between the first channel, the second channel and the thin steel tubes are sealed with epoxy resin, wherein the lower end of the thin steel tube inside the second channel extends out of the lower end surface of the steel block.

[0017] A further improvement of the present invention is:

[0018] The shale is a cylindrical structure, and a third hole and a fourth hole are provided through the shale, and the central axes of the third hole and the fourth hole are parallel to the central axis of the shale;

[0019] Thin steel pipes are placed in the third and fourth channels, and the gaps between the third and fourth channels and the thin steel pipes are sealed with epoxy resin, wherein the upper end of the thin steel pipe in the third channel extends out of the upper end surface of the shale.

[0020] A further improvement of the present invention is:

[0021] The cement stone is a cylindrical structure cast by conventional cement slurry, and the cement stone is penetrated by a fifth hole and a sixth hole;

[0022] The portion of the thin steel pipe in the third channel extending out of the upper end surface of the shale is located in the fifth channel so that the fifth channel is connected to the third channel;

[0023] The portion of the thin steel tube in the second channel that extends out of the lower end surface of the steel block is located in the sixth channel so that the sixth channel is connected to the second channel.

[0024] A further improvement of the present invention is:

[0025] The first hole channel, the interface between the steel block and the cement stone, the fifth hole channel and the third hole channel constitute a first hole channel system of the combined sample;

[0026] The fourth pore channel, the interface between cement stone and shale, the sixth pore channel and the second pore channel constitute a second pore channel system of the combined sample.

[0027] A further improvement of the present invention is:

[0028] The three-axis chamber comprises a three-axis chamber base and a three-axis chamber body arranged on the three-axis chamber base, an upper pressure head is arranged on the top of the three-axis chamber body, and a lower pressure head is arranged on the three-axis chamber base;

[0029] The upper pressure head and the lower pressure head are respectively provided with two channels, and the two ends of the channels are respectively led out from the end face and the side face, and the positions of the holes led out from the end face match the positions of the channels on the end face of the steel block-cement stone-shale combination sample;

[0030] The triaxial chamber base is provided with four base channels, which are respectively connected with corresponding channels led out from the sides of the upper pressure head and the lower pressure head by high-pressure resistant steel pipes, and taper rigid seals are adopted at the joints.

[0031] A further improvement of the present invention is:

[0032] The two groups of test pipelines include a first group of test pipelines and a second group of test pipelines;

[0033] The first group of test pipelines includes a first fluid storage tank and a first fluid collection tank, the first fluid storage tank is connected to a first plunger pump through a pipeline, the first plunger pump is connected to a base channel in the triaxial chamber base through a pipeline, and the base channel is connected to the first channel;

[0034] The first fluid collection tank is connected to a first flow meter through a pipeline, and the first flow meter is connected to a base channel in the base of the three-axis chamber, and the base channel is connected to the third channel.

[0035] A further improvement of the present invention is:

[0036] The second group of test pipelines includes a second fluid storage tank and a second fluid collection tank, the second fluid storage tank is connected to a second plunger pump through a pipeline, the second plunger pump is connected to a base channel in the triaxial chamber base through a pipeline, and the base channel is connected to the fourth channel;

[0037] The second fluid collection tank is connected to a second flow meter through a pipeline, and the second flow meter is connected to a base channel in the base of the three-axis chamber, and the base channel is connected to the second channel.

[0038] A second aspect of the present invention provides a method for synchronously testing the sealing performance of the first and second interfaces of cementing, using the synchronous testing device for the sealing performance of the first and second interfaces of cementing as described above for testing;

[0039] The sealing performance test includes conventional sealing test and sealing test under complex temperature stress loading conditions.

[0040] Compared with the prior art, the present invention has the following beneficial effects:

[0041] (1) The present invention sets two sets of channel systems in the steel block-cement stone-rock combination sample. The two sets of channel systems are independent of each other and can be used to synchronously test the sealing properties of the steel block-cement stone interface (the first cementing interface) and the cement stone-rock interface (the second cementing interface).

[0042] (2) The present invention can simulate complex temperature and pressure load conditions underground, apply complex stress effects such as high-temperature alternating loads to the sample, and at the same time, monitor the sealing evolution / deterioration process of the first and second interfaces of cementing under complex temperature and pressure load conditions in real time and synchronously. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] Figure 1 A structural schematic diagram of a device for synchronously testing the sealing performance of the first and second interfaces of cementing proposed in an embodiment of the present invention;

[0044] Figure 2 It is a three-dimensional schematic diagram of a steel block-cement stone-shale combination sample;

[0045] Figure 3 It is the longitudinal cross-section of the steel block-cement stone-shale combination sample;

[0046] Figure 4 It is a flow chart for the preparation of steel block-cement stone-shale composite samples.

[0047] In the figure, 1, three-axis chamber body, 2, upper pressure head, 3, lower pressure head, 4, three-axis chamber base, 5, steel block, 5-1, first channel, 5-2, second channel, 6, cement stone, 6-1, fifth channel, 6-2, sixth channel, 7, shale, 7-1, third channel, 7-2, fourth channel, 8, first fluid storage tank, 9, first plunger pump, 10, first flow meter, 11, first fluid collecting tank, 12, second fluid storage tank, 13, second plunger pump, 14, second flow meter, 15, second fluid collecting tank. DETAILED DESCRIPTION

[0048] The present invention is further described in detail below in conjunction with the accompanying drawings:

[0049] [Example 1]

[0050] This embodiment provides a device for synchronously testing the sealing performance of the first and second interfaces of cementing, such as Figure 1 As shown, including:

[0051] A three-axis chamber, wherein an upper pressure head and a lower pressure head are arranged in the three-axis chamber;

[0052] The combined sample is arranged between the upper pressure head 2 and the lower pressure head 3, and two sets of channel systems are arranged on the combined sample;

[0053] Two groups of test pipelines are respectively connected to two sets of channel systems on the combined sample.

[0054] Wrap the upper pressure head 2, the combined specimen and the lower pressure head 3 with a high temperature and high pressure heat shrink tube, and heat them with a heat gun for 2 minutes. The heat shrink tube shrinks due to the heat, and tightly wraps the upper pressure head, the combined specimen and the lower pressure head. The heat shrink tube can isolate the hydraulic oil filled in the triaxial chamber in the later stage and transmit the confining pressure to the surrounding of the combined specimen.

[0055] [Example 2]

[0056] like Figure 2 and Figure 3 As shown, the combined sample is a steel block-cement stone-shale combined sample, including a steel block 5, a cement stone 6 and a shale 7 arranged in sequence from top to bottom. The interface between the steel block 5 and the cement stone 6 is used to simulate the first cementing interface, and the interface between the cement stone 6 and the shale 7 is used to simulate the second cementing interface.

[0057] The steel block 5 is a cylindrical structure with a diameter of 100 mm and a height of 50 mm. The steel block 5 is penetrated by a first hole 5-1 and a second hole 5-2, both of which have a diameter of 5 mm. The central axes of the first hole 5-1 and the second hole 5-2 are parallel to the central axis of the steel block 5. The first hole 5-1 and the second hole 5-2 are respectively arranged close to the outer edge of the steel block. Preferably, according to the layout principle of the holes, they are mainly as close to the edge of the sample as possible to make the interface seepage path as long as possible, and at the same time, they should not be too close to the edge of the sample to prevent processing In the process of hole connection, the wall is too thin and breaks. Therefore, the center distance of the first hole 5-1 and the second hole 5-2 from the edge of the steel block is selected to be 10 mm. In the same plane, the angle between the line connecting the central axis of the first hole 5-1 and the second hole 5-2 and the central axis of the steel block is 90°. That is to say, the angle between the line connecting the central axis of the first hole 5-1 and the central axis of the steel block and the line connecting the central axis of the second hole 5-2 and the central axis of the steel block 5 is 90°. This can keep the two hole systems as far away from each other as possible to avoid mutual interference and collusion.

[0058] Thin steel tubes with a diameter of 3 mm are placed in the first channel 5-1 and the second channel 5-2. The gaps between the first channel 5-1, the second channel 5-2 and the thin steel tubes are sealed with epoxy resin. The lower end of the thin steel tube in the second channel 5-2 extends 100 mm beyond the lower end surface of the steel block. The 100 mm extended thin steel tube will be pre-set in a mold and then poured with cement slurry. After the cement slurry solidifies, cement stone is formed. A channel integrated with the second channel 5-2 in the steel block is formed inside the cement stone.

[0059] [Example 3]

[0060] The shale 7 is a cylindrical structure with a diameter of 100 mm and a height of 50 mm. The third channel 7-1 and the fourth channel 7-2 are penetrated by the shale 7, and the central axes of the third channel 7-1 and the fourth channel 7-2 are parallel to the central axis of the shale 7. The third channel 7-1 and the fourth channel 7-2 are respectively arranged close to the outer edge of the rock. Preferably, the center of the third channel 7-1 and the fourth channel 7-2 is 10 mm away from the edge of the rock. In the same plane, the angle between the central axis of the third channel 7-1 and the fourth channel 7-2 and the central axis of the rock is 90°, that is, the angle between the central axis of the third channel 7-1 and the central axis of the rock and the central axis of the fourth channel 7-2 and the central axis of the shale is 90°, so that the two channel systems can be kept as far away from each other as possible to avoid mutual interference and collusion.

[0061] Thin steel tubes with a diameter of 3 mm are placed in the third channel 7-1 and the fourth channel 7-2. The gaps between the third channel 7-1, the fourth channel 7-2 and the thin steel tubes are sealed with epoxy resin. The upper end of the thin steel tube inside the third channel 7-1 extends 100 mm from the upper end surface of the shale. The 100 mm extended thin steel tube will be pre-set in the mold and then poured with cement slurry. After the cement slurry solidifies, cement stone is formed. A channel integrated with the third channel 7-1 in the shale is formed inside the cement stone.

[0062] [Example 4]

[0063] The cement stone 6 is a cylindrical structure with a diameter of 100 mm and a height of 100 mm, and is cast with conventional cement slurry. The cement stone 6 is provided with a fifth channel 6-1 and a sixth channel 6-2, wherein the portion of the thin steel pipe in the third channel 7-1 extending out of the upper end surface of the shale is located in the fifth channel 6-1 so that the fifth channel 6-1 is connected with the third channel 7-1, and the first channel 5-1, the interface between the steel block and the cement stone, the fifth channel 6-1 and the third channel 7-1 constitute a first channel system of the combined sample;

[0064] The portion of the thin steel tube in the second channel 5-2 that extends out of the lower end surface of the steel block is located in the sixth channel 6-2, so that the sixth channel 6-2 is connected to the second channel 5-2, and the fourth channel 7-2, the interface between cement stone and shale, the sixth channel 6-2 and the second channel 5-2 constitute the second channel system of the combined sample.

[0065] [Example 5]

[0066] like Figure 4 As shown, the specific preparation method of the steel block-cement stone-shale combination sample specifically includes the following steps:

[0067] (1) Two channels are made inside the steel block and shale respectively;

[0068] Two through holes with a diameter of 5 mm are prefabricated inside a cylindrical steel block with a diameter of 100 mm and a height of 50 mm, namely a first hole 5-1 and a second hole 5-2. The center of the first hole 5-1 and the second hole 5-2 are 10 mm away from the edge of the steel block, and the angle between the two holes and the line connecting the center of the circle is 90 degrees;

[0069] Two through holes with a diameter of 5 mm are prefabricated inside the shale with a cylindrical structure with a diameter of 100 mm and a height of 50 mm. They are the third hole 7-1 and the fourth hole 7-2. The center of the third hole 7-1 and the fourth hole 7-2 are 10 mm away from the edge of the shale, and the angle between the two holes and the line connecting the center of the circle is 90 degrees.

[0070] (2) A thin steel pipe is inserted into the hole and the annulus is sealed;

[0071] A 3mm diameter thin steel pipe is placed inside the first hole 5-1 and the second hole 5-2 respectively, the annulus is sealed with epoxy resin, and the thin steel pipe inside the second hole 5-2 extends 100mm from the lower end surface of the steel block;

[0072] Thin steel pipes with a diameter of 3 mm are placed inside the third hole channel 7-1 and the fourth hole channel 7-2 respectively, the annuli are sealed with epoxy resin, and the thin steel pipe inside the third hole channel 7-1 extends 100 mm from the upper end surface of the shale.

[0073] (3) Fix the steel block and shale with the pores and capillaries in a mold, pour cement slurry in the middle of the mold to form a cement stone with embedded capillaries in the middle;

[0074] The steel block and shale are placed in a cylindrical mold, and a space is reserved in the middle to pour conventional cement slurry for on-site cementing. Due to the presence of the thin steel pipe, the fifth channel 6-1 and the sixth channel 6-2 in the cement stone are formed during the cement slurry pouring process. The entire mold is placed in a high-temperature and high-pressure curing kettle with a set temperature of 90°C and a pressure of 20MPa. After curing for 28 days, a steel block-cement stone-shale assembly sample containing two sets of channel systems can be obtained after demolding.

[0075] The entire steel block-cement stone-shale combination sample is a cylinder with a diameter of 100 mm and a height of 200 mm. The thickness of the upper steel block is 50 mm, the thickness of the middle cement stone is 100 mm, and the thickness of the bottom shale is 50 mm.

[0076] [Example 6]

[0077] like Figure 1As shown, the triaxial chamber includes a triaxial chamber base 4 and a triaxial chamber body 1 arranged on the triaxial chamber base 4, an upper pressure head 2 is arranged on the top of the triaxial chamber body 1, and a lower pressure head 3 is arranged on the triaxial chamber base 4. The diameters of the upper pressure head 2 and the lower pressure head 3 are both 100 mm, and two channels are respectively arranged on the upper pressure head 2 and the lower pressure head 3. The two ends of the channel are respectively led out from the end face and the side face, and the position of the lead-out hole on the end face coincides with the position of the channel on the end face of the steel block-cement stone-shale combination sample. Specifically, two channels are arranged on the upper pressure head, and the two channels are respectively connected to the first channel 5-1 and the second channel 5-2 on the steel block; two channels are also arranged on the lower pressure head, and the two channels are respectively connected to the third channel 7-1 and the fourth channel 7-2 on the rock;

[0078] Four base channels are arranged on the base 4 of the three-axis chamber, and the base channels are connected with the corresponding channels led out from the sides of the upper pressure head 2 and the lower pressure head 3 by high-pressure resistant steel pipes. The joints are sealed with tapered rigid seals to ensure good sealing performance at the interfaces.

[0079] [Example 7]

[0080] like Figure 1 As shown, the two groups of test pipelines include a first group of test pipelines and a second group of test pipelines, wherein the first group of test pipelines includes a first fluid storage tank 8 and a first fluid collection tank 11, the first fluid storage tank 8 is connected to a first plunger pump 9 through a pipeline, the first plunger pump 9 is connected to a base channel in the triaxial chamber base 4 through a pipeline, and the base channel is connected to the first channel 5-1; the first fluid collection tank 11 is connected to a first flowmeter 10 through a pipeline, the first flowmeter 10 is connected to a base channel in the triaxial chamber base 4, and the base channel is connected to the third channel 7-1. That is, the first sealing test route is formed: the first fluid storage tank 8→the first plunger pump 9→the first channel 5-1→the steel block-cement stone interface→the fifth channel 6-1→the third channel 7-1→the first flowmeter 10→the first fluid collection tank 11.

[0081] The second group of test pipelines includes a second fluid storage tank 12 and a second fluid collection tank 15. The second fluid storage tank 12 is connected to a second plunger pump 13 through a pipeline. The second plunger pump 13 is connected to a base channel in the triaxial chamber base 4 through a pipeline, and the base channel is connected to the fourth channel 7-2. The second fluid collection tank 15 is connected to a second flowmeter 14 through a pipeline. The second flowmeter 14 is connected to a base channel in the triaxial chamber base 4, and the base channel is connected to the second channel 5-2. That is, a second sealing test route is formed: second fluid storage tank 12→second plunger pump 13→fourth channel 7-2→cement stone-shale interface→sixth channel 6-2→second channel 5-2→second flowmeter 14→second fluid collection tank 15.

[0082] The joints of each set of pipelines need to be sealed to ensure good sealing of each set of pipelines.

[0083] [Example 8]

[0084] This embodiment provides a method for synchronously testing the sealing performance of the first and second interfaces of cementing, and the method uses the synchronous device for testing the sealing performance of the first and second interfaces of cementing as described in the above embodiment, and specifically includes the following steps:

[0085] The first step is to assemble a synchronous testing device for the sealing performance of the first and second interfaces of cementing;

[0086] The second step is to use the test device assembled in the first step to test the sealing performance, so as to achieve the synchronous test of the sealing performance of the first and second interfaces of the cementing.

[0087] The sealing performance test includes conventional sealing test and sealing test under complex temperature-stress loading conditions.

[0088] Among them, the conventional sealing test method is to provide a constant pressure at the inlet, on the one hand to monitor whether the pressure can be maintained stable, and on the other hand to monitor whether there is fluid flowing out at the outlet. This is a prior art method and will not be repeated here.

[0089] The sealing test under complex temperature-stress loading conditions is as follows: the triaxial chamber is heated to 90°C at a rate of 2°C / min and maintained for 2 hours to ensure that the entire assembly sample is heated evenly; a confining pressure is applied to 20MPa at a rate of 0.5MPa / s inside the triaxial chamber and maintained for 30 minutes; an axial deviatoric stress is applied to 2MPa at a rate of 0.1MPa / s, and then the axial deviatoric stress is cycled 50 times within the range of 2MPa to 30MPa at a rate of 0.1MPa / s; synchronously, a pressure of 1MPa is formed in the first channel 1-1 and the fourth channel 2-2 by using plunger pump-1 and plunger pump-2, respectively, and the flow rates at the outlets of the third channel 2-1 and the second channel 1-2 are monitored and recorded in real time.

[0090] If the steel block-cement stone interface or / and the cement stone-shale interface deteriorates and is damaged during the mechanical cyclic loading experiment, the fluid flow rate will be detected at the outlet of the third channel 2-1 and the second channel 1-2, and the flow rate changes during the entire experiment will be recorded, thereby achieving simultaneous testing of the sealing performance of the first and second interfaces of cementing under high temperature and complex load conditions.

[0091] The present invention can not only realize the synchronous test of the sealing performance of the first and second interfaces of cementing, but also realize the synchronous test of the two interfaces under high temperature and complex load conditions, which can be closer to the real environment of deep formations.

[0092] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "connected" and "connection" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0093] In the description of the present invention, unless otherwise specified, the terms "upper", "lower", "left", "right", "inside", "outside", etc. indicate directions or positional relationships based on the directions or positional relationships shown in the accompanying drawings. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific direction, be constructed and operated in a specific direction. Therefore, they cannot be understood as limitations on the present invention.

[0094] The above technical solution is only one implementation mode of the present invention. For those skilled in the art, it is easy to make various types of improvements or modifications based on the principles disclosed in the present invention, and it is not limited to the technical solution described in the above specific embodiments of the present invention. Therefore, the above description is only preferred and does not have a restrictive meaning.

Claims

1. A device for synchronously testing the sealing performance of the first and second interfaces of cementing, characterized in that: include: A three-axis chamber, wherein an upper pressure head and a lower pressure head are arranged in the three-axis chamber; A combined sample is arranged between the upper pressure head and the lower pressure head, and the combined sample is provided with two sets of channel systems; Two groups of test pipelines are respectively connected with two sets of channel systems on the combined sample.

2. The device for synchronously testing the sealing performance of the first and second interfaces of cementing according to claim 1, characterized in that: The combined sample is a steel block-cement stone-shale combined sample, which includes a steel block, cement stone and shale arranged in sequence from top to bottom. The interface between the steel block and the cement stone is used to simulate the first cementing interface, and the interface between the cement stone and the shale is used to simulate the second cementing interface.

3. The device for synchronously testing the sealing performance of the first and second interfaces of cementing according to claim 2, characterized in that: The steel block is a cylindrical structure, and a first hole and a second hole are provided through the steel block, and the central axes of the first hole and the second hole are parallel to the central axis of the steel block; Thin steel tubes are placed in the first channel and the second channel, and the gaps between the first channel, the second channel and the thin steel tubes are sealed with epoxy resin, wherein the lower end of the thin steel tube inside the second channel extends out of the lower end surface of the steel block.

4. The device for synchronously testing the sealing performance of the first and second interfaces of cementing according to claim 3, characterized in that: The shale is a cylindrical structure, and a third hole and a fourth hole are provided through the shale, and the central axes of the third hole and the fourth hole are parallel to the central axis of the shale; Thin steel pipes are placed in the third and fourth channels, and the gaps between the third and fourth channels and the thin steel pipes are sealed with epoxy resin, wherein the upper end of the thin steel pipe in the third channel extends out of the upper end surface of the shale.

5. The device for synchronously testing the sealing performance of the first and second interfaces of cementing according to claim 4, characterized in that: The cement stone is a cylindrical structure cast by conventional cement slurry, and the cement stone is penetrated by a fifth hole and a sixth hole; The portion of the thin steel pipe in the third channel extending out of the upper end surface of the shale is located in the fifth channel so that the fifth channel is connected to the third channel; The portion of the thin steel tube in the second channel that extends out of the lower end surface of the steel block is located in the sixth channel so that the sixth channel is connected to the second channel.

6. The device for synchronously testing the sealing performance of the first and second interfaces of cementing according to claim 5, characterized in that: The first hole channel, the interface between the steel block and the cement stone, the fifth hole channel and the third hole channel constitute a first hole channel system of the combined sample; The fourth pore channel, the interface between cement stone and shale, the sixth pore channel and the second pore channel constitute a second pore channel system of the combined sample.

7. The device for synchronously testing the sealing performance of the first and second interfaces of cementing according to claim 6, characterized in that: The three-axis chamber comprises a three-axis chamber base and a three-axis chamber body arranged on the three-axis chamber base, an upper pressure head is arranged on the top of the three-axis chamber body, and a lower pressure head is arranged on the three-axis chamber base; The upper pressure head and the lower pressure head are respectively provided with two channels, and the two ends of the channels are respectively led out from the end face and the side face, and the positions of the holes led out from the end face match the positions of the channels on the end face of the steel block-cement stone-shale combination sample; The triaxial chamber base is provided with four base channels, which are respectively connected with corresponding channels led out from the sides of the upper pressure head and the lower pressure head by high-pressure resistant steel pipes, and a taper rigid seal is adopted at the joints.

8. The device for synchronously testing the sealing performance of the first and second interfaces of cementing according to claim 7, characterized in that: The two groups of test pipelines include a first group of test pipelines and a second group of test pipelines; The first group of test pipelines includes a first fluid storage tank and a first fluid collection tank, the first fluid storage tank is connected to a first plunger pump through a pipeline, the first plunger pump is connected to a base channel in the triaxial chamber base through a pipeline, and the base channel is connected to the first channel; The first fluid collection tank is connected to a first flow meter through a pipeline, and the first flow meter is connected to a base channel in the base of the three-axis chamber, and the base channel is connected to the third channel.

9. The device for synchronously testing the sealing performance of the first and second interfaces of cementing according to claim 8, characterized in that: The second group of test pipelines includes a second fluid storage tank and a second fluid collection tank, the second fluid storage tank is connected to a second plunger pump through a pipeline, the second plunger pump is connected to a base channel in the triaxial chamber base through a pipeline, and the base channel is connected to the fourth channel; The second fluid collection tank is connected to a second flow meter through a pipeline, and the second flow meter is connected to a base channel in the base of the three-axis chamber, and the base channel is connected to the second channel.

10. A method for synchronously testing the sealing performance of the first and second interfaces of cementing, characterized in that: The test is performed using the first and second interface sealing performance synchronous testing device for cementing as described in any one of claims 1 to 9; The sealing performance test includes conventional sealing test and sealing test under complex temperature stress loading conditions.

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