Multi-layer triple-function oil testing system and oil testing process

Abstract

The invention relates to the technical field of oil gas well oil testing, and discloses a multi-layer triple-function oil testing system and an oil testing process. The multi-layer triple-function oil testing system is arranged in a casing at intervals to form an oil sleeve annulus; the multi-layer triple-action oil testing system comprises a testing device, a first oil testing device and a second oil testing device which are sequentially connected from top to bottom through an oil string in a full-bore mode, the first oil testing device can independently conduct oil testing operation on a first reservoir, and the second oil testing device can independently conduct oil testing operation on a second reservoir. According to the technical scheme, the testing device, the first oil testing device and the second oil testing device are in full-bore connection through the tubing string, so that a full-bore fracturing channel is formed, large-displacement fracturing and sand fracturing can be achieved, and the fracturing transformation effect of a reservoir is improved; the first oil testing device and the second oil testing device are adopted to independently achieve testing-liquid drainage-fracturing triple oil testing work for the multiple reservoirs respectively, and the oil testing work efficiency is improved to a large extent.

Description

Technical Field

[0001] This invention relates to the field of oil and gas well testing technology, specifically to a multi-layer triple-operation testing system. Furthermore, it specifically relates to a multi-layer triple-operation testing process. Background Technology

[0002] Currently, for oil and gas reservoirs containing multiple reservoirs, well testing operations are more difficult, costly, and time-consuming. For example, traditional well testing typically uses single-well testing, which involves testing, draining, and fracturing a single reservoir separately, followed by oil or gas production and data analysis. After the well testing of that reservoir is completed, the downhole tubing is moved to test another reservoir. This single-well testing method cannot test multiple reservoirs simultaneously, resulting in low work efficiency, long construction cycles, inability to obtain test data in real time to understand the formation status, and the need for multiple well washes and kills during the well testing process, causing significant contamination of the oil-bearing reservoir.

[0003] At present, there are also related technologies for stratified oil testing, which involves running multiple packers to separate the well space corresponding to the two reservoirs, allowing for independent testing of the two reservoirs. However, existing stratified oil testing also suffers from the inability to obtain test data in real time and promptly grasp the formation status. Furthermore, the fracturing channel of the fracturing string is relatively small, making it impossible to achieve fracturing by adding sand or temporarily plugging balls, thus limiting the reservoir stimulation effect.

[0004] Therefore, there is an urgent need for a new oil testing system to improve the efficiency of oil testing operations, enhance reservoir stimulation effects, and reduce oil testing costs. Summary of the Invention

[0005] The purpose of this invention is to overcome the technical problems of low oil testing efficiency and poor reservoir stimulation effect in the existing technology, and to provide a multi-layer triple-operation oil testing system and oil testing process. This multi-layer triple-operation oil testing system can independently conduct oil testing on multiple reservoirs and has a full-bore fracturing channel, thereby improving the efficiency of oil testing and the effect of reservoir stimulation.

[0006] To achieve the above objectives, a first aspect of the present invention provides a multi-layer triple-operation oil testing system, wherein the multi-layer triple-operation oil testing system is spaced apart within the casing to form an annulus between the casing and the casing. The multi-layer triple-operation oil testing system includes a testing device, a first oil testing device, and a second oil testing device connected sequentially through the tubing string from top to bottom with full bore diameter; wherein the testing device is used to monitor production data within the tubing string and is configured to transmit the production data to the ground in real time.

[0007] The first oil testing device is used to test and fracturing the first reservoir, and the second oil testing device is used to test and fracturing the second reservoir. The second oil testing device includes a tubing plugging switch, which has an open state that connects the tubing string and a closed state that seals the tubing string.

[0008] Through the above technical solution, the testing device, the first oil testing device, and the second oil testing device are connected through a full-bore tubing string, forming a full-bore fracturing channel with a large channel diameter, enabling high-volume fracturing and sand-added fracturing, thereby improving the fracturing and stimulation effect of the reservoir. With the tubing plug switch open, testing is conducted on the second reservoir. The testing device can be used to test the production data of the second reservoir. During the testing process, fluid can be drained through the tubing string. After the testing is completed, the full-bore fracturing channel can be used to stimulate the second reservoir. After the oil testing of the second reservoir is completed, the tubing plug switch is closed, so that the tubing string is located in the upper and lower spaces of the tubing plug switch, respectively, without communication. At this time, the oil testing of the first reservoir is carried out according to the aforementioned second reservoir oil testing steps. Therefore, the multi-layer triple-operation oil testing system provided by this invention independently achieves testing-drainage-fracturing triple-operation oil testing for multiple reservoirs, greatly improving the efficiency of oil testing. Furthermore, the testing device can transmit the production data of the corresponding reservoir to the surface in real time, allowing surface personnel to obtain real-time production data of the underground reservoir. Moreover, the multi-layer triple-operation oil testing system provided by this invention eliminates the need to move the tubing string during oil testing, thereby reducing the risk of well control safety accidents.

[0009] Optionally, the first oil testing device comprises, from top to bottom: a first packer configured to have a set state that seals the annulus and an unsealed state that allows the annulus to connect; a first monitoring module sleeved on the outer peripheral wall of the tubing string; and a first fracturing module for discharging fracturing fluid into the annulus. The second oil testing device comprises, from top to bottom: a second packer configured to have a set state that seals the annulus and an unsealed state that allows the annulus to connect; a tubing plug switch configured to be in a closed state when the pressure inside the tubing string reaches a first predetermined pressure; a second monitoring module sleeved on the outer peripheral wall of the tubing string; and a second fracturing module for discharging fracturing fluid into the annulus.

[0010] Optionally, the first packer and the second packer are configured to be in the setting state when the pressure in the tubing string reaches the setting pressure.

[0011] Optionally, the multi-layer triple-operation oil testing system provided by the present invention further includes a pressure-holding module disposed at the lower part of the second packer. The pressure-holding module is provided with a ball seat for accommodating the first ball. The ball seat is configured to disengage from the pressure-holding module when the pressure in the tubing string reaches a second predetermined pressure, wherein the second predetermined pressure is greater than the setting pressure.

[0012] Optionally, the multi-layer triple-operation oil testing system provided by the present invention further includes a lower section disposed at the lower part of the second oil testing device, the lower section having a receiving space for accommodating the ball seat.

[0013] Optionally, the first packer is configured to be in the unsealed state when the pressure in the annulus reaches the unsealing pressure.

[0014] Optionally, the unsealing pressure is 10-20 MPa higher than the setting pressure.

[0015] Optionally, the second packer is configured to be in the unsealed state when the tubing string is lifted.

[0016] Optionally, the multi-layer triple-operation oil testing system is configured to have a well-washing working mode. In the well-washing working mode, the first packer is in an unsealed state, the second packer is in a set-sealed state, and the first fracturing module is connected to the annulus, so that the well-washing fluid can enter the tubing string from the first fracturing module through the annulus and be discharged to the surface.

[0017] Optionally, the first fracturing module includes a fracturing slide sleeve and a slide sleeve ball seat disposed at the lower part of the fracturing slide sleeve. The fracturing slide sleeve includes an inner slide sleeve seat for accommodating a second ball and an outer slide sleeve seat sleeved on the outer wall of the inner slide sleeve seat. A first injection hole is formed on the outer wall of the outer slide sleeve seat corresponding to the position of the inner slide sleeve seat. The fracturing slide sleeve is configured such that when the pressure in the tubing string reaches a third predetermined pressure, the inner slide sleeve seat can disengage from the outer slide sleeve seat and enter the slide sleeve ball seat.

[0018] Optionally, the second pressure module includes a fracturing guide with a second injection hole formed on its outer peripheral wall.

[0019] Optionally, the testing device includes a test tube for connecting to the tubing string and a test module disposed within the test tube, the test module being configured to be able to retrieve the tubing string from the test tube.

[0020] Optionally, the test module includes a fluid channel configured to be open when the formation pressure is greater than the pressure inside the tubing string, and closed when the formation pressure is less than or equal to the pressure inside the tubing string.

[0021] Optionally, the multi-layer triple-operation oil testing system provided by the present invention further includes a drainage device disposed on the upper part of the first oil testing device. The drainage device is used to discharge the fluid in the oil tubing string and / or the annulus to a storage device on the ground.

[0022] Optionally, the drainage device includes an air lift valve.

[0023] Optionally, there are multiple air lift valves, which are connected sequentially from top to bottom through the oil pipe string.

[0024] Optionally, the multi-layer triple-operation oil testing system provided by the present invention further includes a safety joint disposed between the testing device and the first packer.

[0025] Optionally, the multi-layer triple-operation oil testing system provided by the present invention further includes a hydraulic anchor disposed between the safety joint and the first packer.

[0026] A second aspect of the present invention provides a multi-layer triple-operation oil testing process, employing the aforementioned multi-layer triple-operation oil testing system, comprising the following steps:

[0027] S1, the multi-layer triple-operation oil testing system is lowered into the casing string, so that the first oil testing device corresponds to the first reservoir and the second oil testing device corresponds to the second reservoir.

[0028] S2, conduct oil testing operations on the second reservoir and the first reservoir respectively.

[0029] Optionally, the first oil testing device comprises, from top to bottom: a first packer configured to have a set state for sealing the annulus and an unsealed state for connecting the annulus; a first monitoring module sleeved on the outer peripheral wall of the tubing string; and a first fracturing module for discharging fracturing fluid into the annulus; the second oil testing device comprises, from top to bottom: a second packer configured to have a set state for sealing the annulus and an unsealed state for connecting the annulus; a tubing plugging switch configured to be in a closed state when the pressure inside the tubing string reaches a first predetermined pressure, thereby sealing the tubing string; a second monitoring module sleeved on the outer peripheral wall of the tubing string; and a second fracturing module for discharging fracturing fluid into the annulus.

[0030] Step S2 includes the following steps:

[0031] S21, Perform well opening or well shut-in tests on the second reservoir;

[0032] S22, the fluid in the tubing string and / or the annulus is discharged to the storage device;

[0033] S23, inject fracturing fluid into the second reservoir to fracture the second reservoir;

[0034] S24, Close the oil pipe plugging switch;

[0035] S25, Perform well opening or well shut-in tests on the first reservoir;

[0036] S26, the fluid in the tubing string and / or the annulus is discharged to the liquid storage device;

[0037] S27, inject fracturing fluid into the first reservoir to fracture the first reservoir.

[0038] Optionally, the following steps, performed after step S2, may also be included:

[0039] S3, the first packer is unsealed, and the well-washing fluid is circulated between the annulus and the tubing string. Attached Figure Description

[0040] Figure 1 This is a schematic diagram of the structure of the multi-layer triple-operation oil testing system provided by the present invention.

[0041] Explanation of reference numerals in the attached figures

[0042] 1-Tubing string; 2-Gas lift valve; 3-Testing device; 301-Testing module; 4-Safety joint; 5-Hydraulic anchor; 6-First packer; 7-First monitoring module; 8-Fracturing sleeve; 9-Second packer; 10-Sleeve ball seat; 11-Tubing plugging switch; 12-Ball seat; 13-Second monitoring module; 14-Fracturing guide; 15-First reservoir; 16-Second reservoir; 17-Casing string; 18-Lower sub. Detailed Implementation

[0043] The specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are for illustration and explanation only and are not intended to limit the present invention.

[0044] In this invention, unless otherwise stated, the terms "upper," "lower," "left," "right," "inner," "outer," "top," "bottom," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limiting this invention.

[0045] Furthermore, the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this invention, "multiple" or "multi-layered" means at least two, two layers, such as two, three, two-layered, three-layered, etc., unless otherwise explicitly specified.

[0046] In this invention, the terms "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0047] Furthermore, the terms "S1", "S2", etc. are used for descriptive purposes only and do not indicate a specific order of steps in the method referred to. "S1" is not necessarily the first step, and "S2" can also be performed as the first step. In addition, other steps may be included between "S1" and "S2", so they should not be construed as limitations on the present invention.

[0048] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection, an electrical connection, or a connection that allows communication between them; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise explicitly limited. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0049] Current technologies for well testing in reservoirs with multiple reservoirs typically employ single-well testing. This involves testing, draining, and fracturing a single reservoir separately, followed by oil or gas production and data analysis. After the well testing of that reservoir is completed, the downhole tubing is moved to test another reservoir. This single-well testing method cannot simultaneously test multiple reservoirs, resulting in low efficiency, long construction cycles, and the inability to obtain real-time test data to monitor formation conditions. Furthermore, the need for multiple well washes and kills during the testing process leads to significant contamination of the reservoir. Additionally, there are existing technologies for stratified well testing, which involve running multiple packers to separate the well spaces corresponding to two reservoirs, allowing for independent testing of each reservoir. However, existing stratified well testing also suffers from the inability to obtain real-time test data to monitor formation conditions. Furthermore, the fracturing channels in the fracturing tubing are too small to allow for sand injection or temporary plugging fracturing, limiting the effectiveness of reservoir stimulation.

[0050] This invention addresses the technical problems of low oil testing efficiency and poor reservoir stimulation effect in existing technologies by providing a multi-layer triple-operation oil testing system and oil testing process.

[0051] The first aspect of the present invention provides a multi-layer triple-operation oil testing system, referring to... Figure 1 As shown, the multi-layer triple-operation oil testing system is spaced apart within the casing string 17, thereby forming an annulus between the multi-layer triple-operation oil testing system and the casing string 17. According to one embodiment of the multi-layer triple-operation oil testing system, the oil testing system includes a test device 3, a first oil testing device, and a second oil testing device connected sequentially through the tubing string 1 from top to bottom. The test device 3 is used to monitor production data within the tubing string 1. This production data mainly includes changes in reservoir pressure, reservoir temperature, and reservoir pressure and energy storage temperature after well shut-in. Further, the test device 3 is configured to transmit the monitored production data to the surface in real time. For example, the test device 3 can be connected by a cable, so that the production data monitored by the test device 3 is transmitted to the surface receiving equipment in the form of an electrical signal via the cable; or, the test device 3 includes a test module 301, which is a drop-and-retrieve type. The test module 301 can be retrieved from the tubing string 1 to the surface to read the production data monitored by the test module 301.

[0052] In addition, the first oil testing device can perform oil testing operations on the first reservoir 15, and the second oil testing device can perform oil testing operations on the second reservoir 16. According to one embodiment of the multi-layer triple-operation oil testing system of the present invention, combined with... Figure 1As shown, the first oil testing device includes, from top to bottom, a first packer 6, a first monitoring module 7, and a first fracturing module. The first packer 6 is positioned above the first reservoir 15. The first packer 6 is configured to have a set state (sealing the annulus) and an unsealed state (connecting the annulus). When the first packer 6 is in the set state, the portion of the annulus above the first packer 6 and the portion below the first packer 6 are not connected, thus achieving annulus isolation. The first monitoring module 7 is fitted onto the outer wall of the tubing string 1. The first monitoring module 7 is used to detect production data of the first reservoir 15, such as the pressure and temperature of the first reservoir, and changes in pressure and temperature of the first reservoir 15 after well shut-in. The first fracturing module is used to discharge fracturing fluid into the annulus. The fracturing fluid entering the annulus can further fracture the first reservoir 15, thereby achieving the effect of fracturing the first reservoir 15.

[0053] Continue to refer to Figure 1 As shown, according to one embodiment of the multi-layer triple-operation oil testing system of the present invention, the second oil testing device includes, from top to bottom: a second packer 9, a tubing plugging switch 11, a second monitoring module 13, and a second fracturing module. The second packer 9 is correspondingly disposed between the first reservoir 15 and the second reservoir 16. The second packer 9 is configured to have a set state for sealing the annulus and an unsealed state for connecting the annulus. When the second packer 9 is in the set state, the portion of the annulus above the second packer 9 and the portion below the first packer 9 are not connected, thereby achieving the sealing of the annulus. Thus, when the first packer 6 and the second packer 9 are simultaneously in the set state, the fluid in the first reservoir 15 and the second reservoir 16 does not cross-flow in the annulus. The tubing plugging switch 11 is configured to close when the pressure inside the tubing string 1 reaches a first predetermined pressure, thus sealing the tubing string 1 and preventing communication between the portion of the tubing string 11 above and below it. A second monitoring module 13 is fitted onto the outer peripheral wall of the tubing string 1. This module monitors production data of the second reservoir 16, such as the pressure and temperature of the first reservoir, and changes in pressure and temperature of the second reservoir 16 after well shut-in. A second fracturing module discharges fracturing fluid into the annulus. This fracturing fluid further fracturing the second reservoir 16, achieving the desired fracturing effect.

[0054] In the multi-layer triple-operation oil testing system provided by this invention, the testing device 3, the first oil testing device, and the second oil testing device are connected through the full-bore tubing string 1, forming a full-bore fracturing channel. This fracturing channel has a large diameter, enabling high-volume fracturing and proppant fracturing, thereby improving the fracturing and stimulation effect of the reservoir. Furthermore, the first and second oil testing devices can be used to perform oil testing operations on the first reservoir 15 and the second reservoir 16, respectively. Specifically, the first packer 6 and the second packer 9 are simultaneously in a set-sealed state, thus separating the channels of the first reservoir 15 and the second reservoir 16 in the annulus. Fluids in the first reservoir 15 and the second reservoir 16 do not cross-flow after entering the annulus, which is beneficial for subsequent testing. During oil testing, the second fracturing module is first opened to connect the second reservoir 16 to the tubing string 1. At this time, the production data of the second reservoir can be monitored and obtained using the testing device 3. Fluid entering the annulus and / or tubing string from the second reservoir 16 can be discharged via a self-flowing or the described drainage device. Since the multi-layer triple-operation oil testing system provided by this invention has a full-bore fracturing channel, fracturing fluid can be discharged into the annulus and enter the second reservoir 16 through the second fracturing module, enabling high-volume fracturing or sand-added fracturing of the second reservoir 16, thereby achieving a combined testing-drainage-fracturing oil testing operation for the second reservoir 16. After completing the oil testing of the second reservoir, the tubing plug switch 11 is closed, so that the tubing string 1 is located in the upper and lower spaces of the tubing plug switch 11, respectively, without communication. At this time, the oil testing of the second reservoir 16 proceeds as described above, and the oil testing of the first reservoir 15 is carried out. Therefore, by using the multi-layer triple-operation oil testing system provided by this invention to independently achieve a combined testing-drainage-fracturing oil testing operation for multiple reservoirs, the efficiency of the oil testing operation is greatly improved.

[0055] Furthermore, the present invention provides a multi-layer triple-operation oil testing system in which a first monitoring module 7 and a second monitoring module 13 are respectively fitted onto the outer peripheral wall of the tubing string 1. This ensures that, on the one hand, the first monitoring module 7 and the second monitoring module 13 are fitted onto the outer peripheral wall of the tubing string 1 without affecting the cross-sectional area of ​​the flow channel within the tubing string 1, further guaranteeing the full diameter of the fracturing channel; on the other hand, it prevents the first monitoring module 7 and the second monitoring module 13 from being damaged by the impact and corrosion of the fracturing fluid. Simultaneously, the first monitoring module 7 and the second monitoring module 13 can monitor the first reservoir separately throughout the entire oil testing cycle. The production data of the first reservoir 15 and the second reservoir 16 are monitored and stored. Through subsequent data retrieval, the formation pressure, temperature, and production capacity of the first reservoir 15 and the second reservoir 16 can be analyzed, thereby enabling full-cycle monitoring and evaluation of the reservoir characteristics. Furthermore, during oil testing of the first reservoir 15 or the second reservoir 16, the testing device 3 can detect the corresponding production data of the first reservoir 15 or the second reservoir 16, and the testing device 3 can transmit this production data to the surface in real time, allowing surface personnel to obtain real-time production data of the underground reservoir. Therefore, the multi-layer triple-operation oil testing system of this invention, through the complementary interaction of the testing device 3, the first monitoring module 7, and the second monitoring module 13, achieves both real-time acquisition of reservoir production data and acquisition of reservoir production data throughout its entire lifecycle, thus achieving more comprehensive and accurate reservoir testing.

[0056] Moreover, during the oil testing process of the multi-layer triple-operation oil testing system provided by the present invention, the tubing string 1 remains fixed and does not need to be moved, thereby reducing the risk of well control safety accidents during the movement of the tubing string 1.

[0057] Of course, in the above embodiments, the multi-layer triple-operation oil testing system of the present invention realizes the oil testing of the first reservoir 15 and the second reservoir 16 through the first oil testing device and the second oil testing device respectively. On this basis, the multi-layer triple-operation oil testing system of the present invention can also be equipped with a third oil testing device, a fourth oil testing device, etc., to conduct oil testing for reservoirs with more reservoirs, which will not be elaborated here.

[0058] It should be noted that there are several ways to close the tubing plug switch 11 when the pressure inside the tubing string 1 reaches the first predetermined pressure. For example, the tubing plug switch 11 may be equipped with a ball valve, which closes when the pressure inside the tubing string 1 reaches the first predetermined pressure. However, to simplify the structure and pressure operation of the multi-layer triple-operation oil testing system of the present invention, the tubing plug switch 11 includes a switch tube connected to the tubing string 1, a support plate hinged to the inner wall of the switch tube, a plunger abutting against one side of the support plate via a pin, and a spring abutting against the other side of the support plate and against the inner wall of the switch tube. The plunger has a hollow structure. Thus, when the tubing plug switch 11 is in the open state, the spring is in a compressed state, and the upper tubing string 1 of the tubing plug switch 11 is connected to the lower tubing string 1 through the hollow plunger. A third ball is inserted into tubing string 1. The ball falls onto the plunger and forms a seal, separating the upper tubing string 1 from the lower tubing string 1 of the tubing plug switch 11. Pressure is then applied to tubing string 1. When the pressure reaches a predetermined first pressure, the pin shears, and the plunger, along with the third ball, falls downwards, for example, to the bottom of the well or to the lower section 18 described below. After the plunger falls, under the action of elastic force, the spring pushes the support plate to rotate and seal tubing string 1, keeping the upper tubing string 1 from the lower tubing string 1 of the tubing plug switch 11 in a state of discontinuity. At this time, the tubing plug switch 11 is in the closed state.

[0059] Typically, a packer includes a central tube and a rubber sleeve fitted onto the outer peripheral wall of the central tube. The central tube can be connected to the tubing string. When the packer is in the set position, the rubber sleeve radially abuts against the casing or formation, achieving the packing function. There are several ways to put the packer in the set position. For example, the rubber sleeve can be expandable. Fluid is injected into the tubing string, and pressure is applied to the tubing string 1, causing the fluid to enter the expansion chamber of the rubber sleeve, causing the rubber sleeve to expand and abut against the casing or formation, thus achieving the packing function.

[0060] Alternatively, according to one embodiment of the multi-layer triple-operation oil testing system of the present invention, by pressurizing the tubing string 1, when the pressure in the tubing string 1 reaches the setting pressure, the first packer 6 and the second packer 9 are simultaneously in the setting state, and the fluid in the first reservoir 15 and the second reservoir 16 does not cross-flow in the annulus, so that subsequent oil testing work can be carried out for the first reservoir 15 and the second reservoir 16 respectively.

[0061] It should be noted that pressurizing the tubing string 1 refers to increasing the pressure inside the tubing string 1. There are various ways to pressurize, such as injecting high-pressure liquid or gas into the tubing string 1. The more high-pressure liquid or gas accumulates inside the tubing string 1, the greater the pressure of the liquid column or gas column formed. When the pressure of the liquid column or gas column reaches the setting pressure of the first packer 6 and the second packer 9, the first packer 6 and the second packer 9 are simultaneously in the setting state.

[0062] Optionally, refer to Figure 1 As shown, the multi-layer triple-operation oil testing system provided by the present invention also includes a pressure-holding module disposed below the second packer 9. The pressure-holding module contains a ball seat 12 for accommodating the first ball. The ball seat 12 is configured such that when the pressure inside the tubing string 1 reaches a second predetermined pressure, the ball seat 12 disengages from the pressure-holding module, and the second predetermined pressure is greater than the setting pressure. Thus, when the first ball is inserted into the tubing string 1, it falls along the tubing string 1 to the ball seat 12, where a sealing fit is achieved. Pressure is then applied to the tubing string 1, causing the pressure inside to rise continuously. When the pressure reaches the setting pressure of the first packer 6 and the second packer 9, both the first packer 6 and the second packer 9 are simultaneously in a setting state, sealing the annulus of the oil sleeve. Further pressure is applied to tubing string 1, and the pressure inside tubing string 1 continues to rise. When the pressure reaches the second predetermined pressure, ball seat 12 disengages from the pressure-holding module, and ball seat 12 and the first ball drop fall downwards to the bottom of the well or to the lower section 18 described below. After ball seat 12 disengages from the pressure-holding module, the tubing string 1 is restored to a connected state.

[0063] It should be noted that there are several ways to disengage the ball seat 12 from the pressure-holding module when the pressure inside the tubing string 1 reaches the second predetermined pressure. For example, a pin may be provided between the outer wall of the ball seat 12 and the inner wall of the pressure-holding module. When the pressure inside the tubing string 1 reaches the second predetermined pressure, the ball seat 12 will break the pin under the pressure inside the tubing string 1, thereby disengaging the ball seat 12 from the pressure-holding module. Alternatively, the ball seat 12 may be threadedly connected to the pressure-holding module. When the pressure inside the tubing string 1 reaches the second predetermined pressure, the downward force on the ball seat 12 will exceed the shear strength of the threaded connection, thereby disengaging the ball seat 12 from the pressure-holding module.

[0064] Optionally, refer to Figure 1 As shown above, the multi-layer triple-operation oil testing system of the present invention also includes a lower section 18 disposed at the lower part of the second oil testing device. The lower section has a receiving space for accommodating the ball seat 12. When the ball seat 12 and the first ball dropping device detach from the pressure-holding module, they can fall into the lower section 18 for easy storage. At the same time, the lower section 18 forms a blind end near the bottom of the well in the multi-layer triple-operation oil testing system of the present invention, which is beneficial for the fracturing fluid to be radially injected into the periphery of the fracturing guide 14 below to the second reservoir 16.

[0065] Optionally, as described above, the first packer 6 and the second packer 9 also have an unsealed state, in which the annulus of the oil sleeve is restored to the connected state. There are several ways to put the first packer 6 and the second packer 9 into the unsealed state. For example, if the rubber sleeves of the first packer 6 and the second packer 9 are expandable, fluid is injected into the tubing string 1 and pressurized into the tubing string 1, so that the fluid enters the expansion chamber of the rubber sleeve, causing the rubber sleeve to expand, thereby putting the first packer 6 and the second packer 9 into the set-sealed state; at this time, the pressure in the tubing string 1 is released, so that the rubber sleeve no longer remains in the expanded state, and the first packer 6 and the second packer 9 are put into the unsealed state.

[0066] Alternatively, according to one embodiment of the multi-layer triple-operation oil testing system of the present invention, the first packer 6 is configured to be in an unsealed state when the pressure in the annulus reaches the unsealing pressure. Specifically, the first packer 6 may include a first setting pin and a first unsealing pin. When pressure is applied into the tubing string 1, and the pressure in the tubing string 1 reaches the setting pressure, the first setting pin shears off, causing the rubber sleeve of the first packer 6 to be axially compressed and abut against the inner wall of the tubing string 17, thereby sealing the annulus. When pressure is applied into the annulus, and the pressure in the annulus reaches the unsealing pressure, the first unsealing pin shears off, causing the rubber sleeve of the first packer 6 to no longer maintain an axially compressed state, thereby restoring the annulus to a connected state, i.e., the first packer 6 is in an unsealed state.

[0067] In one embodiment of the multi-layer triple-operation oil testing system of the present invention, the unsealing pressure of the first packer 6 is 10-20 MPa higher than its setting pressure, so as to facilitate the control of the setting and unsealing of the first packer 6.

[0068] Of course, as mentioned above, the second packer 9 can also be configured to pressurize the annulus. When the pressure in the annulus reaches the unsealing pressure of the second packer 9, the second packer 9 is in an unsealed state. Alternatively, the second packer 9 can be configured to be in an unsealed state when the tubing string 1 is lifted. Specifically, the second packer 9 may include a second setting pin and a second unsealing pin. Pressurizing the tubing string 1, when the pressure in the tubing string 1 reaches the setting pressure, the second setting pin shears off, causing the rubber sleeve of the second packer 9 to be axially compressed and abut against the inner wall of the tubing string 17, thus sealing the annulus. When the tubing string 1 is lifted by ground lifting equipment, such as a crane, when the lifting force on the second unsealing pin exceeds its own structural strength, the second unsealing pin shears off, causing the rubber sleeve of the second packer 9 to no longer maintain an axially compressed state, thus restoring the annulus to a connected state, i.e., the second packer 9 is in an unsealed state.

[0069] Optionally, the multi-layer triple-operation oil testing system provided by the present invention is configured with a well-washing mode. In the well-washing mode, the first packer 6 is in an unsealed state, the second packer 9 is in a set-sealed state, and the first fracturing module is connected to the annulus, so that the well-washing fluid can enter the tubing string 1 through the annulus and be discharged to the surface. Figure 1 As shown, after fracturing of the first reservoir located between the first packer 6 and the second packer 9, especially after proppant fracturing, some sand particles remain on the top of the second packer 9, or even become trapped between the top of the second packer 9 and the inner wall of the casing string 17. This can easily cause sand jamming in the packer, affecting the subsequent unsealing of the second packer 9 and the retrieval of the multi-layer triple-operation oil testing system. To address this, by unsealing the first packer 6 while keeping the second packer 9 in a set state, well-washing fluid is injected into the annulus. This well-washing fluid enters the tubing string 1 through the annulus from the first fracturing module and is then returned to the surface. This cycle is repeated multiple times to clean the sand particles remaining on the top of the second packer 9, thus preventing sand jamming in the second packer 9.

[0070] Meanwhile, to ensure that the first packer 6 is in the unsealed state and the second packer 9 is in the set state when pressurizing the annulus, the unsealing pressure of the second packer 9 needs to be significantly higher than that of the first packer 6, for example, more than 50 MPa higher. In this situation, if pressurizing the annulus is still used to unseal the second packer 9, a relatively high annulus pressure is required, making the unsealing operation difficult and prone to safety accidents. Therefore, this invention unseals the second packer 9 by lifting the tubing string 1. A ground crane can easily provide a relatively large lifting force, for example, greater than the unsealing pressure of the aforementioned second unsealing pin, thus making the second packer 9 easier to unseal and avoiding safety accidents caused by injecting high pressure into the annulus.

[0071] Optionally, the first fracturing module and the second fracturing module can have various implementations. For example, the first fracturing module and the second fracturing module can be tubing. Before oil testing, a perforation gun is inserted into the tubing to form a hole, thereby connecting the reservoir and the tubing string. Alternatively, to reduce construction difficulty and cost, according to one embodiment of the multi-layer triple-operation oil testing system of the present invention, refer to... Figure 1As shown, the first fracturing module includes a fracturing sleeve 8 and a sleeve ball seat 10 disposed at the lower part of the fracturing sleeve 8. The fracturing sleeve 8 includes an inner sleeve seat for accommodating the second ball and an outer sleeve seat fitted on the outer wall of the inner sleeve seat. A first injection hole is formed on the outer wall of the outer sleeve seat corresponding to the position of the inner sleeve seat. The fracturing sleeve 8 is configured such that when the pressure in the tubing string 1 reaches a third predetermined pressure, the inner sleeve seat can detach from the outer sleeve seat and enter the sleeve ball seat 10. Specifically, during the first reservoir 15 oil testing, the second ball is dropped into the tubing string 1. The second ball falls downward onto the inner sleeve seat, forming a sealed fit with the inner sleeve seat, pressurizing the tubing string 1. When the pressure in the tubing string 1 reaches the third predetermined pressure, the inner sleeve seat detaches from the outer sleeve seat, and the inner sleeve seat, along with the second ball, falls into the sleeve ball seat 10. When the inner sleeve seat separates from the outer sleeve seat, the first injection hole on the outer wall of the outer sleeve seat can be connected to the tubing string 1. At this time, the first reservoir 15, the annulus and the tubing string 1 are in a connected state, thereby establishing the oil testing channel of the first reservoir 15.

[0072] Of course, there are several ways to disengage the inner sleeve from the outer sleeve when the pressure inside the tubing string 1 reaches the third predetermined pressure. For example, a pin may be installed between the outer wall of the inner sleeve and the inner wall of the outer sleeve. When the pressure inside the tubing string 1 reaches the third predetermined pressure, the inner sleeve will break the pin under the pressure inside the tubing string 1, thus disengaging the inner sleeve from the outer sleeve. Alternatively, the inner sleeve may be threadedly connected to the outer sleeve. When the pressure inside the tubing string 1 reaches the third predetermined pressure, the inner sleeve will experience a downward force greater than the shear strength of the threaded connection, thus disengaging the inner sleeve from the outer sleeve.

[0073] It should be noted that the sliding ball seat 10 can be set above the second packer 9, or the sliding ball seat 10 can be set below the second packer 9 and above the oil pipe plugging switch 11. In this way, when the pressure inside the oil pipe string 1 reaches the third predetermined pressure, the inner seat of the sliding sleeve, together with the second ball, falls onto the sliding ball seat 10 and seals the oil pipe string 1 at the lower part of the sliding ball seat 10, so that the pressure inside the oil pipe string 1 can replenish the pressure of the second packer 9, and further keep the second packer 9 in the set seal state.

[0074] Optionally, in one embodiment of the multi-layer triple-operation oil testing system of the present invention, the second pressure module includes a fracturing guide with a second injection hole formed on its outer peripheral wall. The tubing string 1 establishes an oil testing channel with the annulus and the second reservoir 16 through the second injection hole in order to carry out oil testing.

[0075] As mentioned above, by inserting the first ball into the tubing string 1, the first packer 6 and the second packer 9 are set in a sealed state; by inserting the third ball into the tubing string 1, the tubing plug switch 11 is closed; by inserting the second ball into the tubing string 1, the fracturing sleeve 8 is connected to the first reservoir. According to one embodiment of the multi-layer triple-operation oil testing system of the present invention, the diameter of the first ball is smaller than the diameter of the third ball, and the diameter of the third ball is smaller than the diameter of the second ball. The ball seat 12, the plunger, and the inner seat of the sleeve all have hollow structures. The first ball and the ball seat 12 can form a sealed fit, and the first ball can pass through the hollow structures of the plunger and the inner seat of the sleeve respectively; the third ball and the plunger can form a sealed fit, and the third ball can pass through the hollow structure of the inner seat of the sleeve; the second ball and the inner seat of the sleeve can form a sealed fit.

[0076] Optionally, refer to Figure 1 As shown, the testing device 3 includes a test tube body for connecting to the tubing string 1 and a test module 301 disposed within the test tube body. The test module 301 includes a monitoring sensor for monitoring the fluid pressure and temperature inside the tubing string 1, thereby monitoring the production data of the first reservoir 15 or the second reservoir 16. Moreover, the test module 301 is configured to be retrieved from the tubing string 1 from the test tube body. For example, the test module 301 is connected to the ground via a steel wire. When it is necessary to read the production data monitored by the test module 301 or in other situations where it is necessary to remove the test module 301, the test module 301 can be removed by pulling up the steel wire.

[0077] Optionally, the test module 301 includes a fluid channel that can be kept normally open to allow fluid to pass through smoothly. Alternatively, in one embodiment of the invention, the fluid channel is configured to be open when the formation pressure is greater than the pressure inside the tubing string 1, and closed when the formation pressure is less than or equal to the pressure inside the tubing string 1. That is, when the formation pressure, for example, the pressure of the first or second reservoir, is greater than the pressure inside the tubing string 1, fluid in the formation can enter the test module 301 through the fluid channel to conduct oil testing. When the formation pressure is less than or equal to the pressure inside the tubing string 1, fluid in the formation no longer enters the tubing string 1. Therefore, the test module 301 not only serves to establish an oil testing channel for conducting oil testing, but also serves to seal the tubing string 1.

[0078] In one embodiment, the test module 301 specifically includes two interconnected upper and lower chambers. A valve ball is installed in the lower chamber, which can block the entrance of the lower chamber. The axial connection between the upper and lower chambers does not overlap with the entrance of the lower chamber. When the pressure in the tubing string 1 above the test module 301 is greater than the pressure below it, the valve ball blocks the entrance of the lower chamber, preventing fluid from entering the test module 301, i.e., preventing fluid from the formation from entering the test module 301. When the pressure in the tubing string 1 above the test module 301 is less than the pressure below it, the valve ball moves upward under the pressure in the tubing string 1 below the test module 301. At this time, the entrance of the lower chamber is no longer blocked, and fluid from the formation enters the lower chamber through the lower chamber entrance, and then enters the upper chamber through the connecting channel. It continues to flow upward from the outlet of the upper chamber and flows to the surface for storage.

[0079] In existing technologies, MFE testing devices and APR testing devices are commonly used for oil testing. The MFE testing device typically has a valve stem installed in the tubing string 1, connected to a ball valve in the fluid channel. The opening and closing of the fluid channel is controlled by the up-and-down movement of the valve stem. This prevents the MFE testing device from achieving a full-bore connection with the tubing string 1, thus hindering high-volume fracturing and proppant fracturing. Furthermore, the up-and-down movement of the drill pipe is required to open and close the fluid channel. In addition, the APR testing device requires pressurizing the tubing string 1 to open and close the fluid channel, and the pressure varies in different areas of the APR testing device. Therefore, this places high demands on the sealing of all components of the APR testing device and makes the pressurization operation of the tubing string 1 quite complex.

[0080] The test module 301 of this invention can open and close the fluid channel by means of the pressure difference between the tubing string 1 and the formation pressure, making operation very simple. Moreover, the test module 301 is a drop-and-retrieve type. Before reservoir fracturing, the test module 301 can be retrieved to the surface. At this time, the test tube body and the tubing string 1 form a full-bore connection, which is beneficial for high-volume fracturing and sand fracturing, thereby further improving the effect of reservoir fracturing stimulation.

[0081] As mentioned above, during the oil testing process, the formation pressure is high enough that the fluid in the tubing string 1 can be discharged by self-flowing. Optionally, when the formation oil and gas production is low, the discharge volume is small, and the liquid properties are unclear, the multi-layer triple-operation oil testing system of the present invention can use a discharge device to discharge the oil and gas fluid in the tubing string 1 and / or the annulus to the liquid storage device on the ground. The discharge device is located on the upper part of the first oil testing device.

[0082] The drainage device can be a hydraulic pump or other device, as long as it can discharge the oil and gas fluid in the tubing string 1 and / or the annulus to the surface. In one embodiment of the invention, the drainage device includes a gas lift valve 2, which includes a working cylinder and a working valve installed on the working cylinder. The working cylinder is located above the first oil testing device and connected to the tubing string 1, and gas lift drainage is performed by injecting nitrogen into the well. Furthermore, a valve bag is formed on the outer wall of the working cylinder, and the working valve is installed in the valve bag. This ensures that the working cylinder and the tubing string 1 are connected in full bore, which is beneficial for high-volume fracturing and sand fracturing, thereby further improving the effect of reservoir fracturing.

[0083] Optionally, depending on the reservoir depth and the design requirements for fluid discharge in oil and gas wells, there are multiple gas lift valves 2. Multiple gas lift valves 2 are connected sequentially from top to bottom through tubing string 1 to form a multi-stage gas lift valve for fluid discharge. During fluid discharge, nitrogen is injected into the annulus through a surface nitrogen truck. The nitrogen is compressed in the well and reaches the preset pressure of the working valve. The working valve opens, and nitrogen enters the tubing string 1 from the working valve, thereby lifting the fluid in the tubing string 1 to the surface storage device, such as a metering tank.

[0084] Optionally, refer to Figure 1 As shown, the multi-layer triple-operation oil testing system of the present invention also includes a safety joint 4 disposed between the testing device 3 and the first packer 6. When a failure occurs downhole, the safety joint 4 is disengaged from the lower tubing string 1 by rotating the tubing string 1 at the wellhead on the surface and simultaneously lifting the tubing string 1, thereby pulling the safety joint 4 and the upper tubing string 1 out of the wellbore.

[0085] Optionally, refer to Figure 1 As shown, the multi-layer triple-operation oil testing system of the present invention also includes a hydraulic anchor 5 disposed between the safety joint 4 and the first packer 6. The hydraulic anchor 5 includes a hydraulic anchor tube body and anchor claws disposed on the peripheral wall of the hydraulic anchor tube body. The anchor claws have an initial state and an anchored state. When the anchor claws are in the initial state, they do not protrude radially from the hydraulic anchor tube body; when the anchor claws are in the anchored state, they extend radially. Specifically, the multi-layer triple-operation oil testing system of the present invention is lowered into the casing string 17. After reaching the predetermined position, pressure is applied to the tubing string 1. Because the pressure inside the tubing string 1 is higher than the pressure inside the annulus, the anchor claws of the hydraulic anchor 5 are in the anchored state, extending and embedding into the inner wall of the casing string 17, thereby assisting in fixing the tubing string 1 and preventing axial displacement of the tubing string 1. After the oil testing work is completed, the pressure in the tubing string 1 is released, and the pressure inside the tubing string 1 is lower than the pressure inside the annulus. The anchor claws are in the initial state and retract into the hydraulic anchor tube body to facilitate the removal of the tubing string 1.

[0086] It should be noted that in the multi-layer triple-operation oil testing system of the present invention, the positional relationship between the gas lift valve 2, the testing device 3, the safety connector 4, and the hydraulic anchor 5 can be arbitrary, as long as the gas lift valve 2, the testing device 3, the safety connector 4, and the hydraulic anchor 5 are located above the first packer 6. Of course, in order to make the production data monitored by the testing device 3 more accurately reflect the actual situation of the reservoir, the testing device 3 can be set close to the first packer 6. At the same time, in order to ensure that the testing device 3 and the gas lift valve 2 can be pulled out of the wellbore along with the tubing string 1 after the safety connector 4 is disengaged, the testing device 3 and the gas lift valve 2 are set above the safety connector 4. The hydraulic anchor tube of the hydraulic anchor 5 is connected to the central tube of the first packer 6 so as to facilitate the hydraulic anchor 5 to assist in fixing the tubing string 1 and the first packer 6. Thus, the hydraulic anchor 5 is connected to the top of the first packer 6, the safety connector 4 is set on the upper part of the hydraulic anchor 5, the test device 3 is set on the upper part of the safety connector 4, and the test device 3 and the safety connector 4 are set as close as possible to the first packer 6. The gas lift valve 2 can be set on the upper part of the safety connector 4. The specific number and position of the valves are determined according to the reservoir depth and the drainage design requirements.

[0087] A second aspect of the present invention provides a multi-layer triple-operation oil testing process, which employs the aforementioned multi-layer triple-operation oil testing system and includes the following steps:

[0088] S1, the multi-layer triple oil testing system is lowered into the casing string 17, so that the first oil testing device corresponds to the first reservoir 15 and the second oil testing device corresponds to the second reservoir 16.

[0089] S2, oil testing operations were carried out on the second reservoir 16 and the first reservoir 15 respectively.

[0090] According to one embodiment of the multi-layer triple-operation oil testing process of the present invention, step S2 above includes the following steps:

[0091] S21, Perform well opening or shut-in tests on the second reservoir 16;

[0092] S22, drain the fluid from tubing string 1 and / or the annulus to the storage device;

[0093] S23, inject fracturing fluid into the second reservoir 16 to fracture the second reservoir 16;

[0094] S24, Close the oil pipe plugging switch 11;

[0095] S25, conduct well opening or shut-in tests on the first reservoir 15;

[0096] S26, drain the fluid from tubing string 1 and / or the annulus into the storage device;

[0097] S27, inject fracturing fluid into the first reservoir 15 to fracture the first reservoir 15.

[0098] Optionally, the multi-layer triple-operation oil testing process of the present invention further includes the following steps performed after step S2:

[0099] S3, the first packer 6 is released, and the well washing fluid is circulated between the annulus and the tubing string 1.

[0100] The following describes in detail one embodiment of the multi-layer triple-operation oil testing process of the present invention:

[0101] On the ground, the air lift valve 2, testing device 3, safety joint 4, hydraulic anchor 5, first packer 6, first monitoring module 7, fracturing sleeve 8, second packer 9, sleeve ball seat 10, tubing plug switch 11, ball seat 12, second monitoring module 13, fracturing guide 14, and lower short section 18 are connected and assembled through tubing string 1 to form the aforementioned multi-layer triple-unit oil testing system. This oil testing system is lowered into a predetermined position within casing string 17, spaced apart from casing string 17 to form an annulus. At this point, first packer 6 is located above first reservoir 15, and second packer 9 is located below first reservoir 15 and above second reservoir 16. A first ball is dropped into tubing string 1. The first ball falls onto ball seat 12, pressurizing tubing string 1. When the pressure inside tubing string 1 reaches the setting pressure, first packer 6 and second packer 9 are in the setting state. Continue pressurizing the tubing string 1. When the pressure inside the tubing string 1 reaches the second predetermined pressure, the ball seat 12 disengages from the pressure-holding module, and the ball seat 12, along with the first ball drop, falls into the lower sub 18. At this point, the second reservoir 16 establishes a testing channel with the multi-layer triple-operation testing system, allowing for testing of the second reservoir 16. Testing can be conducted in either the well-opened or well-closed state. Using the second monitoring module 13 and testing device 3 in conjunction, real-time and full-cycle production data of the second reservoir can be obtained. The fluid in the tubing string 1 and / or the annulus is discharged to the surface storage device using the gas lift valve 2. Based on the production data from the testing of the second reservoir 16, if the daily oil and gas production of the second reservoir 16 is low, especially if it does not reach the industrial oil and gas flow rate, production enhancement measures such as fracturing and acidizing can be implemented to increase the production of the second reservoir 16. Specifically, fracturing fluid can be injected into the tubing string 1. The fracturing fluid is discharged through the fracturing guide 14 to the annulus, enters the second reservoir 16, and fracturing the second reservoir 16, thereby completing the fracturing stimulation of the second reservoir 16.

[0102] After completing the combined testing, drainage, and fracturing operation for the second reservoir 16, the testing of the first reservoir 15 can be carried out. A third ball is dropped into the tubing string 1. The third ball falls to the tubing plug switch 11, forming a sealed fit with the plunger, pressurizing the tubing string 1. When the pressure inside the tubing string 1 reaches the first predetermined pressure, the plunger, along with the third ball, falls to the lower section 18, and the tubing plug switch 11 is closed. The second ball is dropped into the tubing string 1. The second ball falls onto the inner seat of the fracturing sleeve 8, pressurizing the tubing string 1. When the pressure inside the tubing string 1 reaches the third predetermined pressure, the inner seat of the sleeve, along with the second ball, falls onto the ball seat of the sleeve. At this time, the fracturing sleeve 8 is connected to the first reservoir 15, thereby establishing the oil testing channel for the first reservoir 15. The testing-drainage-fracturing oil testing work of the first reservoir 15 is carried out. The specific process is the same as the testing-drainage-fracturing oil testing work of the second reservoir 16 mentioned above, and will not be repeated here.

[0103] To avoid sand jamming in the second packer, which could prevent the multi-layer triple-operation oil testing system of this invention from being pulled out of the wellbore, after completing the testing-fluid drainage-fracture triple-operation oil testing of the first reservoir 15, well washing can be performed. Specifically, pressure is applied to the annulus to release the first packer 6, while the second packer 9 remains in the set state. Well washing fluid is injected into the annulus, flowing through the annulus and from the fracturing sleeve 8 into the tubing string 1, and then back to the surface. The well washing fluid circulates repeatedly between the annulus and the tubing string 1 until the residual sand particles on the top of the second packer 9 are cleaned. The tubing string 1 is then pulled up, simultaneously releasing the second packer 9, and the multi-layer triple-operation oil testing system of this invention is pulled out of the wellbore. This completes the oil testing of the oil and gas reservoir including the first reservoir 15 and the second reservoir 16.

[0104] It should be noted that, in order to ensure that the first, second, and third ball drops, as well as the sand-adding fracturing fluid and acidizing fracturing fluid, pass through the testing device 3 better without damaging the testing module 301, the testing module 301 can be retrieved from the well before the first, second, and third ball drops and the sand-adding fracturing fluid and acidizing fracturing fluid are injected, and then lowered back into the well during the testing work.

[0105] The preferred embodiments of the present invention have been described in detail above with reference to the accompanying drawings; however, the present invention is not limited thereto. Within the scope of the inventive concept, various simple modifications can be made to the technical solutions of the present invention, including combinations of various specific technical features in any suitable manner. To avoid unnecessary repetition, the present invention will not describe the various possible combinations separately. However, these simple modifications and combinations should also be considered as the content disclosed in the present invention and are all within the protection scope of the present invention.

Claims

1. A multi-layer triple-operation oil testing system, characterized in that, The multi-layer triple oil testing system is spaced within the casing string (17) to form an oil-casing annulus. The multi-layer triple oil testing system includes a test device (3), a first oil testing device, and a second oil testing device that are connected sequentially through the oil casing string (1) from top to bottom with full bore. Among them, the testing device (3) is used to monitor the production data in the tubing string (1) and is configured to transmit the production data to the ground in real time; The first oil testing device is used to test and fracturing the first reservoir (15), and the second oil testing device is used to test and fracturing the second reservoir (16). The second oil testing device includes a tubing plug switch (11), which has an open state that connects the tubing string (1) and a closed state that seals the tubing string (1).

2. The multi-layer triple-operation oil testing system according to claim 1, characterized in that, The first oil testing device comprises, from top to bottom: The first packer (6) is configured to have a set state that seals the annulus and an unsealed state that connects the annulus. A first monitoring module (7) is fitted onto the outer peripheral wall of the tubing string (1); and, A first fracturing module is used to discharge fracturing fluid into the annulus of the oil casing; The second oil testing device comprises, from top to bottom: The second packer (9) is configured to have a setting state that seals the annulus and an unsealing state that connects the annulus. The tubing plugging switch (11) is configured to be in a closed state when the pressure inside the tubing string (1) reaches a first predetermined pressure; The second monitoring module (13) is sleeved on the outer peripheral wall of the tubing string (1); and, The second fracturing module is used to discharge the fracturing fluid into the annulus of the oil casing.

3. The multi-layer triple-operation oil testing system according to claim 2, characterized in that, The first packer (6) and the second packer (9) are configured to be in the setting state when the pressure inside the tubing string (1) reaches the setting pressure.

4. The multi-layer triple-operation oil testing system according to claim 3, characterized in that, It also includes a pressure-holding module disposed at the lower part of the second packer (9), wherein the pressure-holding module is provided with a ball seat (12) for accommodating the first ball, the ball seat (12) is configured to disengage from the pressure-holding module when the pressure in the tubing string (1) reaches a second predetermined pressure, the second predetermined pressure being greater than the setting pressure.

5. The multi-layer triple-operation oil testing system according to claim 4, characterized in that, It also includes a lower section (18) disposed at the lower part of the second oil testing device, the lower section having a receiving space for accommodating the ball seat (12).

6. The multi-layer triple-operation oil testing system according to claim 3, characterized in that, The first packer (6) is configured to be in the unsealed state when the pressure in the annulus reaches the unsealing pressure.

7. The multi-layer triple-operation oil testing system according to claim 6, characterized in that, The unsealing pressure is 10-20 MPa higher than the setting pressure.

8. The multi-layer triple-operation oil testing system according to claim 6, characterized in that, The second packer (9) is configured to be in the unsealed state when the tubing string (1) is lifted.

9. The multi-layer triple-operation oil testing system according to claim 8, characterized in that, The multi-layer triple-operation oil testing system is configured with a well-washing working mode. In the well-washing working mode, the first packer (6) is in the unsealed state, the second packer (9) is in the set-sealed state, and the first fracturing module is connected to the annulus so that the well-washing fluid can enter the tubing string (1) from the first fracturing module through the annulus and be discharged to the ground.

10. The multi-layer triple-operation oil testing system according to claim 2, characterized in that, The first fracturing module includes a fracturing sleeve (8) and a sleeve ball seat (10) disposed at the lower part of the fracturing sleeve (8). The fracturing sleeve (8) includes an inner sleeve seat for accommodating a second ball and an outer sleeve seat sleeved on the outer wall of the inner sleeve seat. A first injection hole is formed on the outer wall of the outer sleeve seat corresponding to the position of the inner sleeve seat. The fracturing sleeve (8) is configured such that when the pressure in the tubing string (1) reaches a third predetermined pressure, the inner sleeve seat can disengage from the outer sleeve seat and enter the sleeve ball seat (10).

11. The multi-layer triple-operation oil testing system according to claim 2, characterized in that, The second fracturing module includes a fracturing guide (14) with a second injection hole formed on its outer peripheral wall.

12. The multi-layer triple-operation oil testing system according to claim 2, characterized in that, The testing device (3) includes a test tube body for connecting to the tubing string (1) and a test module (301) disposed in the test tube body, the test module (301) being configured to be able to retrieve the tubing string (1) from the test tube body.

13. The multi-layer triple-operation oil testing system according to claim 12, characterized in that, The test module (301) includes a fluid channel configured to be open when the formation pressure is greater than the pressure inside the tubing string (1) and closed when the formation pressure is less than or equal to the pressure inside the tubing string (1).

14. The multi-layer triple-operation oil testing system according to claim 2, characterized in that, It also includes a draining device located on the upper part of the first oil testing device, the draining device being used to discharge the fluid in the oil tubing string (1) and / or the annulus to the ground.

15. The multi-layer triple-operation oil testing system according to claim 14, characterized in that, The draining device includes an air lift valve (2).

16. The multi-layer triple-operation oil testing system according to claim 15, characterized in that, The number of air lift valves (2) is multiple, and the multiple air lift valves (2) are connected sequentially from top to bottom through the oil pipe string (1).

17. The multi-layer triple-operation oil testing system according to any one of claims 2-16, characterized in that, It also includes a safety connector (4) disposed between the test device (3) and the first packer (6).

18. The multi-layer triple-operation oil testing system according to claim 17, characterized in that, It also includes a hydraulic anchor (5) disposed between the safety joint (4) and the first packer (6).

19. A multi-layer triple-cropping oil testing process, characterized in that, The multi-layer triple-operation oil testing system according to any one of claims 1-17 includes the following steps: S1, the multi-layer triple-operation oil testing system is lowered into the casing string (17), so that the first oil testing device corresponds to the first reservoir (15) and the second oil testing device corresponds to the second reservoir (16). S2, oil testing operations are carried out on the second reservoir (16) and the first reservoir (15) respectively.

20. The multi-layer triple-operation oil testing process according to claim 19, characterized in that, The first oil testing device comprises, from top to bottom: The first packer (6) is configured to have a set state that seals the annulus and an unsealed state that connects the annulus. A first monitoring module (7) is fitted onto the outer peripheral wall of the tubing string (1); and, A first fracturing module is used to discharge fracturing fluid into the annulus of the oil casing; The second oil testing device comprises, from top to bottom: The second packer (9) is configured to have a setting state that seals the annulus and an unsealing state that connects the annulus. A tubing plugging switch (11) is configured to be closed when the pressure inside the tubing string (1) reaches a first predetermined pressure, so as to seal the tubing string (1). The second monitoring module (13) is sleeved on the outer peripheral wall of the tubing string (1); and, A second fracturing module is used to discharge fracturing fluid into the annulus of the oil casing; Step S2 includes the following steps: S21, perform well opening or well shut-in tests on the second reservoir (16); S22, the fluid in the tubing string (1) and / or the annulus is discharged to the storage device; S23, inject fracturing fluid into the second reservoir (16) to fracture the second reservoir (16); S24, close the oil pipe plugging switch (11); S25, perform well opening or well shut-in tests on the first reservoir (15); S26, the fluid in the tubing string (1) and / or the annulus is discharged to the storage device; S27, inject fracturing fluid into the first reservoir (15) to fracture the first reservoir (15).

21. The multi-layer triple-operation oil testing process according to claim 20, characterized in that, It also includes the following steps performed after step S2: S3, the first packer (6) is unsealed, and the well washing fluid is circulated between the annulus and the tubing string (1).

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