Rodless lifting tubular column, system, method and related application thereof

Abstract

The invention discloses a rodless lifting tubular column, a system, a method and related application thereof. The tubular column comprises a plurality of lifting modules which are connected; the lifting module comprises a coiled tubing, a motor and a monitoring device which are sequentially arranged from top to bottom, and a screw pump and a flexible shaft which are arranged in the motor; the screw pump comprises a screw and a screw pump stator arranged outside the screw in a sleeving mode. An inner hole of each component is communicated with a cavity of the screw pump to form an oil conveying cavity, and the adjacent oil conveying cavities are communicated with each other; the motor comprises a motor stator and a motor rotor, and the motor rotor is used for driving the screw pump stator to rotate, so that crude oil is lifted in the lifting module where the motor is located and enters the lifting module at the upper end of the motor; the monitoring device is connected with the control cabinet so as to monitor the first pressure of the crude oil entering the lifting modules from the suction inlet of the oil conveying cavity in real time and transmit the first pressure to the control cabinet so that the motors in the lifting modules where the monitoring device is located can be sequentially controlled to work through the control cabinet. And deep well lifting can be carried out.

Description

Technical Field

[0001] This invention relates to the field of oil and gas exploration and development technology, and in particular to a rodless lifting tubing string, system, method and related applications. Background Technology

[0002] With the deepening of exploration and development, deep and ultra-deep resources have become the main drivers of increased reserves and production. The number of deep and ultra-deep oil and gas reservoirs is constantly increasing, and several deep oil and gas fields, including Tarim, Southwest, and Turpan-Hami, have been established. In the process of oil and gas field development, well lifting is a crucial step; well lifting refers to the process of raising crude oil from a well to the surface. Currently, well lifting methods generally include rod-assisted lifting and rodless lifting.

[0003] Among them, the rod-lift method specifically uses a pumping unit as a power source to lift crude oil to the surface through a sucker rod and a pump; the rodless lift method specifically uses a power cable to drive a downhole motor, which in turn drives a downhole pump to extract oil and lift crude oil to the surface. Summary of the Invention

[0004] The inventors of this application have discovered that deep and ultra-deep well lifting technology has become a significant factor restricting the development of deep oil and gas. In existing technologies, when using pumping units to lift oil wells, the weight of the sucker rod and the lifting capacity of the pumping unit limit the length of the sucker rod. If the sucker rod is too long, the weight of the entire sucker rod becomes excessive, increasing its elasticity and easily leading to low efficiency of the deep well pump, large stroke loss, and failure to lift the downhole fluid to the surface. Therefore, rod-based lifting is generally suitable for conventional oil wells. In existing rodless lifting methods, a single motor is used as the power source. Due to the limitation of the wellhead diameter, the size of the motor is limited, resulting in limited output power. At the same time, due to the difficulty in processing and installing screw pumps, the processing length and lifting height of the screw pump are limited. Therefore, existing rodless lifting methods cannot meet the needs of deep and ultra-deep well lifting. In the current technology, there is no single lifting method that can meet the corresponding lifting requirements in the lifting of deep and ultra-deep (above 3000 meters) oil wells. Therefore, it is an urgent problem to solve to provide a lifting method to meet the lifting requirements of deep and ultra-deep oil wells.

[0005] In view of the above problems, the present invention is proposed to provide a rodless lifting column that overcomes or at least partially solves the above problems, comprising: a plurality of lifting modules connected in sequence;

[0006] The lifting module includes, from top to bottom, a continuous oil pipe, a motor, a monitoring device, and a screw pump and a flexible shaft installed inside the motor;

[0007] The screw pump includes a screw and a screw pump stator sleeved outside the screw, with a cavity formed between the screw pump stator and the screw;

[0008] The monitoring device inner hole, the motor inner hole, the cavity and the continuous oil pipe inner hole are sequentially connected to form the oil supply chamber of the lifting module, and the oil supply chambers of adjacent lifting modules are interconnected.

[0009] The motor includes: a motor stator connected to one end of the flexible shaft, and a motor rotor disposed outside the screw pump stator, so that the rotation of the motor rotor drives the screw pump stator to rotate, thereby lifting the crude oil in the lifting module where the motor is located and entering the lifting module located above it; the other end of the flexible shaft is connected to the screw.

[0010] The monitoring device is connected to the control cabinet to monitor in real time the first pressure of crude oil entering the lifting module where the monitoring device is located from the suction port at the lower end of the oil delivery chamber, and transmits the first pressure to the control cabinet so that the control cabinet can control the motors in the lifting module where the monitoring device is located to work in sequence.

[0011] In an optional embodiment, the rodless lifting column provided in this invention further includes a pressure sensor;

[0012] The pressure sensor is located between the continuous tubing and the motor to monitor the second pressure of crude oil at the annulus outlet of the screw pump in real time.

[0013] In an optional embodiment, the temperature resistance of the motors and screw pumps of the lifting modules, from top to bottom, increases sequentially.

[0014] In an optional embodiment, the coiled tubing is a cable-laying coiled tubing, comprising: a metal-based coiled tubing and a cable-laying layer disposed on its exterior;

[0015] The cable layer is equipped with heating cables and power cables. The power cables are used to connect the motor and the control cabinet to provide power to the downhole motor.

[0016] The heating cable is used to connect to the control cabinet to heat the liquid in the metal-based continuous tubing based on the control signal from the control cabinet.

[0017] Accordingly, the monitoring device is connected to the control cabinet via a power cable or a heating cable.

[0018] In an optional embodiment, the monitoring device is further configured to monitor the temperature of crude oil entering the lifting module where the monitoring device is located from the suction port, and transmit the temperature to the control cabinet;

[0019] Accordingly, the control cabinet is also used to generate a control signal based on the temperature to control the heating cable to heat the metal-based continuous tubing.

[0020] In an optional embodiment, the lifting module further includes an upper connector and a lower connector;

[0021] The upper and lower connectors of adjacent lifting modules are sealed together.

[0022] Based on the same inventive concept, this invention also provides a rodless lifting system, including: a control cabinet and the above-mentioned rodless lifting column;

[0023] The control cabinet is located at the wellhead and is connected to the motors and monitoring devices of each lifting module of the rodless lifting string. It receives the first pressure transmitted by the monitoring devices of each lifting module and controls the motors in the lifting modules where the monitoring devices are located to work sequentially from bottom to top based on the first pressure.

[0024] In an optional embodiment, the control cabinet is also used to receive a second pressure transmitted by the pressure sensors of each lifting module;

[0025] Based on the relationship between the first pressure difference and the first pressure within the same lifting module and the first preset pressure difference, it determines whether the working state of the screw pump within the lifting module is abnormal, and issues an early warning if the working state is abnormal; and / or, based on the relationship between the second pressure difference and the second pressure within the upper lifting module and the lower lifting module within adjacent lifting modules and the second preset pressure difference, it determines whether the working state of the lifting section between the pressure sensor of the lower lifting module and the monitoring device of the upper lifting module within adjacent lifting modules is abnormal, and issues an early warning if the working state is abnormal.

[0026] In an optional embodiment, the control cabinet is further configured to receive the temperature of crude oil monitored by the monitoring device in each lifting module, and control the heating cable of the lifting module where the monitoring device is located and at least one lifting module located below the lifting module to heat the crude oil based on the temperature and the corresponding preset temperature threshold.

[0027] Based on the same inventive concept, embodiments of the present invention also provide a rodless lifting method for oil wells, implemented based on the aforementioned modular rodless lifting system, comprising:

[0028] Connect the rodless lifting string to the surface control cabinet and lower the rodless lifting string into the well.

[0029] After the rodless lifting string is lowered into place, the motor of the lifting module at the bottom of the rodless lifting string is controlled by the control cabinet. The rotation of the motor rotor drives the stator of the screw pump to rotate to start the well lifting.

[0030] After the crude oil in the well is lifted into the next lifting module, the monitoring device of the lifting module detects the first pressure and transmits the first pressure to the control cabinet. The control cabinet controls the motor of the lifting module where the monitoring device is located to work based on the received first pressure, so as to achieve continuous lifting of the oil well through the lifting module.

[0031] Based on the pressure monitored by each monitoring device, the control cabinet sequentially controls the motors in the corresponding lifting modules of each monitoring device to start working from bottom to top, until the motor of the lifting module at the top of the rodless lifting string starts working, so as to achieve oil well lifting through the entire rodless lifting string.

[0032] Based on the same inventive concept, this invention also provides an application of the above-mentioned rodless lifting string and the above-mentioned rodless lifting system in the field of oil and gas exploration and development technology.

[0033] The beneficial effects of the above-described technical solutions provided in the embodiments of the present invention include at least the following:

[0034] The rodless lifting string provided in this embodiment of the invention is configured as a structure with multiple lifting modules interconnected. Each lifting module is equipped with a monitoring device to monitor in real time the first pressure of crude oil entering the lifting module containing the monitoring device from the suction port at the lower end of the oil delivery chamber. This first pressure is transmitted to a control cabinet connected to the monitoring device. The control cabinet generates a control signal for the motor based on the first pressure, and the motors in each lifting module sequentially start operating from top to bottom according to the control signal from the control cabinet to perform oil well lifting operations. In other words, the rodless lifting string provided in this embodiment of the invention is configured as a structure with multiple power sources. The number of lifting modules included in the rodless lifting string can be selected according to the lifting depth. Through the direct relay of power from different modules, deep well lifting is completed, which can solve the problem that existing lifting methods are insufficient for lifting deep and ultra-deep oil wells.

[0035] Other features and advantages of the invention will be set forth in the description which follows, and will be apparent in part from the description, or may be learned by practicing the invention. The objects and other advantages of the invention may be realized and obtained by means of the structures particularly pointed out in the written description, claims, and drawings.

[0036] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Attached Figure Description

[0037] The accompanying drawings are provided to further illustrate the invention and form part of the specification. They are used in conjunction with embodiments of the invention to explain the invention and do not constitute a limitation thereof. In the drawings:

[0038] Figure 1 This is a schematic diagram of the structure of the rodless lifting system in an embodiment of the present invention;

[0039] Figure 2 This is a schematic diagram of the lifting module in an embodiment of the present invention;

[0040] Figure 3 This is a schematic diagram of the structure of the continuous tubing in an embodiment of the present invention.

[0041] Explanation of reference numerals in the attached figures:

[0042] 100. Lifting module; 200. Control cabinet; 101. Upper connector; 102. Continuous tubing; 103. Pressure sensor; 104. Screw pump; 105. Flexible shaft; 106. Motor; 107. Monitoring device; 108. Lower connector; 109. Oil delivery chamber; 1091. Suction port;

[0043] 1021. Metal-based coiled tubing; 1022. Cable layer; 1023. Power cable; 1024. Heating cable; 1041. Screw pump stator; 1042. Screw. Detailed Implementation

[0044] Exemplary embodiments of the present disclosure will now be described in more detail with reference to the accompanying drawings. While exemplary embodiments of the present disclosure are shown in the drawings, it should be understood that the present disclosure may be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the disclosure to those skilled in the art.

[0045] In the description of this invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," 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 the invention and for 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 limitations on the invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0046] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0047] To address the problem that there is no single lifting method in the existing technology that can adapt to the lifting of deep and ultra-deep (above 3000 meters) oil wells, embodiments of the present invention provide a rodless lifting string, system, method and related applications.

[0048] An embodiment of the present invention provides a rodless lifting column, referring to... Figure 1 and Figure 2 As shown, it includes: multiple lifting modules 100 connected in sequence;

[0049] The lifting module 100 includes: a continuous oil pipe 102, a motor 106, a monitoring device 107 arranged from top to bottom, and a screw pump 104 and a flexible shaft 105 arranged in the motor 106;

[0050] The screw pump 104 includes a screw and a screw pump stator 1041 sleeved outside the screw 1042, with a cavity formed between the screw pump stator 1041 and the screw 1042;

[0051] The monitoring device inner hole, the motor inner hole, the cavity and the continuous oil pipe inner hole are sequentially connected to form the oil delivery chamber 109 of the lifting module 100, and the oil delivery chambers 109 of adjacent lifting modules 100 are interconnected.

[0052] The motor 106 includes a motor stator connected to one end of the flexible shaft 105, and a motor rotor disposed outside the screw pump stator 1041. The rotation of the motor rotor drives the screw pump stator 1041 to rotate, thereby lifting the crude oil in the lifting module 100 where the motor 106 is located, and allowing it to enter the lifting module 100 located above it. The other end of the flexible shaft 105 is connected to the screw 1042. The flexible shaft 105 can resolve the contradiction between the eccentric movement of the screw pump 104 and the concentric movement of the submersible motor 106.

[0053] The monitoring device 107 is connected to the control cabinet 200 to monitor in real time the first pressure of crude oil entering the lifting module 100 where the monitoring device 107 is located from the suction port 1091 at the lower end of the oil delivery chamber 109, and transmit the first pressure to the control cabinet 200 so that the motor 106 in the lifting module 100 where the monitoring device 107 is located can be controlled sequentially through the control cabinet 200.

[0054] The rodless lifting string provided in this embodiment of the invention is configured as a structure in which multiple lifting modules 100 are interconnected. Each lifting module 100 is equipped with a monitoring device 107 to monitor in real time the first pressure of crude oil entering the lifting module 100 containing the monitoring device 107 from the suction port 1091 at the lower end of the oil delivery chamber 109 of the lifting module 100. This first pressure is transmitted to a control cabinet 200 connected to the monitoring device 107. The control cabinet 200 generates a control signal for a motor 106 based on the first pressure. The motors 106 in each lifting module 100 then sequentially start operating from bottom to top according to the control signal from the control cabinet 200 to perform oil well lifting operations. In other words, the rodless lifting string provided in this embodiment of the invention is configured as a structure with multiple power sources. The number of lifting modules 100 included in the rodless lifting string can be selected based on the lifting depth. Through the direct relay of power from different modules, deep well lifting can be completed, solving the problem that existing lifting methods are insufficient for lifting deep and ultra-deep wells.

[0055] It should be noted that the embodiments of the present invention do not specifically limit the height of liquid that each lifting module 100 can lift (i.e., the length of each lifting module 100), and can be designed according to needs in actual use. Preferably, the lengths of each lifting module 100 are the same to facilitate storage, transportation, and operation, and a standard coiled tubing machine can be used for operation. Accordingly, the number of lifting modules 100 can be selected according to the required well depth and the lifting height of each lifting module 100. For example, if each lifting module 100 can lift the same volume of liquid to a height of 1000 meters, then three lifting modules 100 are needed when applying to lifting wells with a pumping depth of 3000 meters; and six lifting modules 100 are needed when applying to lifting wells with a pumping depth of 6000 meters. Furthermore, the embodiments of the present invention do not specifically limit the type of motor 106 used in each lifting module 100, as long as it can achieve the corresponding function. For example, the motor 106 can be a permanent magnet synchronous motor.

[0056] Meanwhile, during rodless lifting, as the screw pump stator 1041 rotates with the motor rotor, a dynamic seal is used between the motor 106 and the screw pump 104 and their upper components to prevent crude oil from entering the motor 106 and causing damage. Furthermore, the pressure on the upper parts of the motor 106 and screw pump 104 is related to the liquid column above them during lifting. If the lifting string is too long, the dynamic seal may fail, affecting normal lifting operations. These factors also limit the length of the lifting string. However, the structure of the multi-lifting module 100 provided in this embodiment allows for selection of the length of each lifting module 100 as needed, effectively solving the problem of high-pressure dynamic seals while meeting the lifting requirements of deep and ultra-deep wells.

[0057] In one embodiment, refer to Figure 2 As shown, the lifting module 100 also includes an upper connector 101 and a lower connector 108;

[0058] The upper connector 101 and lower connector 108 of adjacent lifting modules 100 are sealed together. Specifically, the upper and lower connectors 108 of each lifting module 100 can be connected by flanges to achieve a quick, safe, reliable and convenient connection between adjacent lifting modules 100.

[0059] In one embodiment, refer to Figure 2 As shown, the rodless lifting column provided in this embodiment of the invention also includes a pressure sensor 103;

[0060] Specifically, the pressure sensor 103 is located between the continuous tubing 102 and the motor 106 to monitor the second pressure of crude oil at the oil delivery annulus outlet of the screw pump 104 in real time.

[0061] In practical applications, pressure sensor 103 is also used to connect to control cabinet 200. Control cabinet 200 can also be used to receive the second pressure and, based on the relationship between the first pressure difference and the first pressure difference between the second pressure and the first pressure in the same lifting module 100, determine whether the working status of screw pump 104 in the lifting module 100 is abnormal, and issue an early warning reminder in case of abnormal working status, so as to monitor the working status of screw pump 104 in real time.

[0062] And / or, based on the relationship between the second pressure difference and the second pressure of the upper lifting module 100 and the lower lifting module 100 within the adjacent lifting modules 100, and the second preset pressure difference, determine whether the working state of the lifting section between the pressure sensor 103 of the lower lifting module 100 and the monitoring device 107 of the upper lifting module 100 within the adjacent lifting modules 100 is abnormal, and issue an early warning reminder if the working state is abnormal.

[0063] The first preset differential pressure can be determined based on the first theoretical differential pressure between the outlet and inlet of the screw pump 104. When the difference between the first differential pressure between the actual monitored second pressure and the first pressure and the first theoretical differential pressure is within the allowable fluctuation error, the screw pump 104 is judged to be in normal working condition. If the difference between the first differential pressure and the first theoretical differential pressure is outside the allowable fluctuation error, the screw pump 104 is judged to be in abnormal working condition. For example, the designed first theoretical differential pressure between the outlet and inlet of the screw pump 104 is 10 MPa, and the allowable fluctuation error is 1 MPa. However, when the actual monitoring shows a first differential pressure between the second pressure and the first pressure of 5 MPa, the screw pump 104 is judged to be in abnormal working condition. At this time, the control cabinet 200 will issue an early warning reminder, and the staff can perform corresponding operations according to the early warning reminder, thereby ensuring the safe and stable operation of the lifting operation.

[0064] Similarly, the second preset differential pressure value can be determined based on the second theoretical differential pressure value of the lifting section between the pressure sensor 103 of the lower lifting module 100 and the monitoring device 107 of the upper lifting module 100 in the adjacent lifting modules 100. When the difference between the second differential pressure and the second theoretical differential pressure is within the allowable fluctuation error, the working state of the lifting section is judged to be normal; if the difference between the second differential pressure and the second theoretical differential pressure is outside the allowable fluctuation error, the working state of the lifting section is judged to be abnormal, for example... When the second differential pressure increases relative to the second theoretical differential pressure, it may be due to a blockage in the oil pipeline. When the second differential pressure decreases relative to the second theoretical differential pressure, it may be due to a poor seal between the upper connector 101 and the lower connector 108 of the two adjacent lifting modules 100, or damage to the casing of the lifting section causing crude oil leakage. All of these will affect the normal lifting of the oil well. At this time, the control cabinet 200 will issue an early warning. The staff can take corresponding measures based on the early warning to ensure the normal operation of the lifting operation.

[0065] It should be noted that the specific values ​​of the first preset pressure difference and the second preset pressure difference are not specifically limited in this embodiment, and can be selected according to the actual situation.

[0066] In one embodiment, the motors 106 and screw pumps 104 of each lifting module 100 in the rodless lifting string have the same temperature resistance, or the temperature resistance of the motors 106 and screw pumps 104 of each lifting module 100 increases sequentially from top to bottom. Since the well temperature gradually increases with the increase of formation depth, it is preferred that the temperature resistance of the motors 106 and screw pumps 104 of each lifting module 100 increases sequentially from top to bottom. It should be noted that the specific temperature resistance requirements for the motor 106 and screw pump 104 of each lifting module 100 are not specifically limited in this embodiment of the invention. They can be selected according to actual needs to adapt to the lifting requirements under different depth conditions. For example, when applied to a pump hanging depth of 3000 meters and using 3 lifting modules 100 to complete the lifting, the 3 lifting modules 100 are arranged from top to bottom as follows, based on the well temperature and displacement requirements: a 60-degree temperature resistant module (i.e., the temperature resistance of the motor 106 and screw pump 104 is 60 degrees), a 90-degree temperature resistant module, and a 120-degree temperature resistant module.

[0067] In the lifting string provided in this embodiment of the invention, when designing the lifting module 100, the materials of the motor 106 and screw pump 104 in each lifting module 100 are selected according to the requirements of the well conditions to meet different temperature resistance requirements. This design can save costs while better adapting to the requirements of different well conditions.

[0068] In one embodiment, refer to Figure 3 As shown, the continuous tubing 102 in this embodiment is a cable-laying continuous tubing 102, including: a metal-based continuous tubing 1021 and a cable-laying layer 1022 disposed on its exterior.

[0069] The cable layer 1022 is equipped with a heating cable 1024 and a power cable 1023. The power cable 1023 is used to connect the motor 106 and the control cabinet 200 to provide power to the downhole motor 106.

[0070] Heating cable 1024 is used to connect to control cabinet 200 to heat the liquid in metal-based continuous tubing 1021 based on control signals from control cabinet 200;

[0071] Accordingly, the monitoring device 107 is connected to the control cabinet 200 via a power cable 1023 or a heating cable 1024.

[0072] Furthermore, the monitoring device 107 in this embodiment of the invention is also used to monitor the temperature of crude oil entering the lifting module 100 where the monitoring device 107 is located from the suction port 1091, and transmit the temperature to the control cabinet 200.

[0073] Accordingly, the control cabinet 200 is also used to generate a control signal based on the temperature to control the heating cable 1024 to heat the metal-based continuous tubing 1021. Specifically, the monitoring device 107 mentioned in this embodiment can be a temperature and pressure sensor 103.

[0074] In practical applications, the control cabinet 200 is also used to control the lifting module 100 where the monitoring device 107 is located, and the heating cable 1024 of at least one lifting module 100 located below the monitoring device 107 to heat the crude oil based on the temperature of the crude oil monitored by the monitoring device 107 in each lifting module 100 and the corresponding preset temperature threshold. Specifically, the preset temperature threshold can be determined based on the wax precipitation point of the crude oil to be lifted. This preset temperature threshold should be greater than or equal to the wax precipitation point of the crude oil. During the process of lifting crude oil to the surface, the temperature will decrease as it flows within the lifting tubing. When the temperature drops below the wax precipitation point of the crude oil, substances such as wax and gum asphalt in the crude oil will be adsorbed onto the inner wall of the tubing, thus affecting the lifting effect. Moreover, the probability of this situation increases with the increase of lifting depth. Therefore, the monitoring device 107 monitors the temperature of the crude oil, and the control cabinet 200 controls the lifting module 100 where the monitoring device 107 is located, and the heating cable 1024 of at least one lifting module 100 located below the lifting module 100, based on the temperature and the preset temperature threshold, to heat the oil. This can reduce the precipitation and adsorption of substances such as wax and gum asphalt in the crude oil onto the inner wall of the tubing, thus ensuring the lifting effect when lifting crude oil in deep and ultra-deep wells.

[0075] The following is an exemplary description of the applicable method of the rodless lifting module 100 provided in the embodiments of the present invention: the rodless lifting string is connected to the ground control cabinet 200, and the rodless lifting string is lowered into the preset position in the well.

[0076] After the rodless lifting string is lowered into place, the motor 106 of the lifting module 100 at the bottom of the rodless lifting string is controlled by the control cabinet 200. The rotation of the motor rotor drives the stator 1041 of the screw pump to rotate to start the well lifting.

[0077] After the crude oil in the well is lifted into the previous lifting module 100, the monitoring device 107 of the lifting module 100 detects the first pressure and transmits the first pressure to the control cabinet 200. The control cabinet 200 controls the motor 106 of the lifting module 100 where the monitoring device 107 is located to work based on the received first pressure, so as to achieve continuous lifting of the oil well through the lifting module 100.

[0078] Based on the pressure monitored by each monitoring device 107, the control cabinet 200 sequentially controls the motors 106 in the lifting modules 100 corresponding to each monitoring device 107 to start working from bottom to top, until the motor 106 of the lifting module 100 located at the top of the rodless lifting string starts working, so as to achieve oil well lifting through the entire rodless lifting string.

[0079] When the rodless lifting string provided in this embodiment of the invention is applied, the control cabinet 200 only controls the motor 106 of the lifting module 100 where the monitoring device 107 located above the lowest lifting module 100 detects the pressure. That is, the control cabinet 200 controls the motor 106 in each lifting module 100 to open and operate from bottom to top. This can avoid the situation where the motor 106 at the top is idling for too long during oil well lifting, and can also save energy. When the controller controls the motor to start, the controller can generate a control signal based on the initial first pressure detected by the monitoring device, or it can determine whether the first pressure exceeds a preset pressure threshold based on the received first pressure and generate a control signal after the first pressure exceeds the preset pressure threshold. This embodiment of the invention does not make specific limitations on this.

[0080] Based on the same inventive concept, referring to Figures 1 to 3 As shown, this embodiment of the invention also provides a rodless lifting system, including: a control cabinet 200 and the above-mentioned rodless lifting column;

[0081] The control cabinet 200 is located at the wellhead and is connected to the motors 106 and monitoring devices 107 of each lifting module 100 of the rodless lifting string. It receives the first pressure transmitted by the monitoring devices 107 of each lifting module 100 and controls the motors 106 in each lifting module 100 where the monitoring devices 107 are located to work sequentially from bottom to top based on the first pressure.

[0082] In one embodiment, the control cabinet 200 is also used to receive a second pressure transmitted by the pressure sensor 103 of each lifting module 100;

[0083] Based on the relationship between the first pressure difference and the first pressure within the same lifting module 100, the system determines whether the working state of the screw pump 104 within the lifting module 100 is abnormal, and issues an early warning if the working state is abnormal; and / or, based on the relationship between the second pressure difference and the second pressure within adjacent lifting modules 100, the system determines whether the working state of the lifting section between the pressure sensor 103 of the lower lifting module 100 and the monitoring device 107 of the upper lifting module 100 is abnormal, and issues an early warning if the working state is abnormal.

[0084] In one embodiment, the control cabinet 200 is also used to receive the temperature of crude oil monitored by the monitoring device 107 in each lifting module 100, and to control the lifting module 100 where the monitoring device 107 is located, and the heating cable of at least one lifting module 100 located below the lifting module 100 to perform heating based on the temperature and the corresponding preset temperature threshold.

[0085] The specific structure of the rodless lifting column and the specific application of the control cabinet of the rodless lifting system provided in the embodiments of the present invention will be described in detail in the above embodiments regarding the rodless lifting column, and will not be described in detail here.

[0086] Based on the same inventive concept, embodiments of the present invention also provide a rodless lifting method for oil wells, implemented based on the aforementioned modular rodless lifting system, comprising:

[0087] Connect the rodless lifting string to the surface control cabinet and lower the rodless lifting string into the well.

[0088] After the rodless lifting string is lowered into place, the motor of the lifting module at the bottom of the rodless lifting string is controlled by the control cabinet. The rotation of the motor rotor drives the stator of the screw pump to rotate to start the well lifting.

[0089] After the crude oil in the well is lifted into the next lifting module, the monitoring device of the lifting module detects the first pressure and transmits the first pressure to the control cabinet. The control cabinet controls the motor of the lifting module where the monitoring device is located to work based on the received first pressure, so as to achieve continuous lifting of the oil well through the lifting module.

[0090] Based on the pressure monitored by each monitoring device, the control cabinet sequentially controls the motors in the corresponding lifting modules of each monitoring device to start working from bottom to top, until the motor of the lifting module at the top of the rodless lifting string starts working, so as to lift the oil well through the entire rodless lifting string.

[0091] Regarding the rodless lifting method for oil wells in the above embodiments, the specific methods by which each module performs its operations have been described in detail in the embodiments related to the system, and will not be elaborated upon here.

[0092] Based on the same inventive concept, embodiments of the present invention also provide an application of the above-described rodless lifting string and the above-described rodless lifting system in the field of oil and gas exploration and development technology.

[0093] It should be understood that the specific order or hierarchy of steps in the disclosed process is an example of an exemplary method. Based on design preferences, it should be understood that the specific order or hierarchy of steps in the process may be rearranged without departing from the scope of this disclosure. The appended method claims provide elements of various steps in an exemplary order and are not intended to limit the scope to the specific order or hierarchy described.

[0094] In the detailed description above, various features are combined together in a single embodiment to simplify this disclosure. This approach to disclosure should not be construed as reflecting an intention that embodiments of the claimed subject matter require more features than are explicitly stated in each claim. Rather, as reflected in the appended claims, the invention is presented with fewer features than all of the features in a single disclosed embodiment. Therefore, the appended claims are hereby explicitly incorporated into the detailed description, wherein each claim stands alone as a preferred embodiment of the invention.

[0095] The foregoing description includes examples of one or more embodiments. It is certainly impossible to describe all possible combinations of components or methods in order to describe the above embodiments, but those skilled in the art will recognize that further combinations and arrangements of the various embodiments are possible. Therefore, the embodiments described herein are intended to cover all such changes, modifications, and variations that fall within the scope of the appended claims. Furthermore, the term "comprising" as used in the specification or claims is interpreted in a manner similar to the term "including," as interpreted when used as a conjunction in the claims. Additionally, the use of any term "or" in the specification of the claims is intended to mean "non-exclusive or."

Claims

1. A rodless lifting string, characterized in that, include: Multiple lifting modules connected in sequence; The lifting module includes, from top to bottom, a continuous oil pipe, a motor, a monitoring device, and a screw pump and a flexible shaft installed inside the motor; The screw pump includes a screw and a screw pump stator sleeved outside the screw, with a cavity formed between the screw pump stator and the screw; The monitoring device inner hole, the motor inner hole, the cavity and the continuous oil pipe inner hole are sequentially connected to form the oil supply chamber of the lifting module, and the oil supply chambers of adjacent lifting modules are interconnected. The motor includes: a motor stator connected to one end of the flexible shaft, and a motor rotor disposed outside the screw pump stator, so that the rotation of the motor rotor drives the screw pump stator to rotate, thereby lifting the crude oil in the lifting module where the motor is located and entering the lifting module located above it; the other end of the flexible shaft is connected to the screw. The monitoring device is connected to the control cabinet to monitor in real time the first pressure of crude oil entering the lifting module where the monitoring device is located from the suction port at the lower end of the oil delivery chamber, and transmits the first pressure to the control cabinet so that the control cabinet can control the motors in the lifting module where the monitoring device is located to work in sequence.

2. The rodless lifting column as described in claim 1, characterized in that, It also includes pressure sensors; The pressure sensor is located between the continuous tubing and the motor to monitor the second pressure of crude oil at the annulus outlet of the screw pump in real time.

3. The rodless lifting string as described in claim 1, characterized in that, The temperature resistance of the motors and screw pumps of the lifting modules, from top to bottom, increases sequentially.

4. The rodless lifting string as described in claim 1, characterized in that, The coiled tubing is a cable-laying coiled tubing, comprising: a metal-based coiled tubing and a cable-laying layer disposed on its exterior; The cable layer is equipped with heating cables and power cables. The power cables are used to connect the motor and the control cabinet to provide power to the downhole motor. The heating cable is used to connect to the control cabinet to heat the liquid in the metal-based continuous tubing based on the control signal from the control cabinet. Accordingly, the monitoring device is connected to the control cabinet via a power cable or a heating cable.

5. The rodless lifting string as described in claim 4, characterized in that, The monitoring device is also used to monitor the temperature of crude oil entering the lifting module where the monitoring device is located from the suction port, and transmit the temperature to the control cabinet. Accordingly, the control cabinet is also used to generate a control signal based on the temperature to control the heating cable to heat the metal-based continuous tubing.

6. The rodless lifting string as described in any one of claims 1-5, characterized in that, The lifting module further includes: an upper connector and a lower connector; The upper and lower connectors of adjacent lifting modules are sealed together.

7. A poleless lifting system, characterized in that, include: Control cabinet and the rodless lifting column as described in any one of claims 1-6; The control cabinet is located at the wellhead and is connected to the motors and monitoring devices of each lifting module of the rodless lifting string. It receives the first pressure transmitted by the monitoring devices of each lifting module and controls the motors in the lifting modules where the monitoring devices are located to work sequentially from bottom to top based on the first pressure.

8. The poleless lifting system as described in claim 7, characterized in that, The control cabinet is also used to receive the second pressure transmitted by the pressure sensors of each lifting module; Based on the relationship between the first pressure difference and the first pressure within the same lifting module and the first preset pressure difference, it determines whether the working state of the screw pump within the lifting module is abnormal, and issues an early warning if the working state is abnormal; and / or, based on the relationship between the second pressure difference and the second pressure within the upper lifting module and the lower lifting module within adjacent lifting modules and the second preset pressure difference, it determines whether the working state of the lifting section between the pressure sensor of the lower lifting module and the monitoring device of the upper lifting module within adjacent lifting modules is abnormal, and issues an early warning if the working state is abnormal.

9. The poleless lifting system as described in claim 7 or 8, characterized in that, The control cabinet is also used to receive the temperature of crude oil monitored by the monitoring device in each lifting module, and to control the lifting module where the monitoring device is located, and the heating cable of at least one lifting module located below the lifting module to heat the oil based on the temperature and the corresponding preset temperature threshold.

10. A rodless lifting method for oil wells, characterized in that, Based on the modular, poleless lifting system as described in any one of claims 7-9, including: Connect the rodless lifting string to the surface control cabinet and lower the rodless lifting string into the well. After the rodless lifting string is lowered into place, the motor of the lifting module at the bottom of the rodless lifting string is controlled by the control cabinet. The rotation of the motor rotor drives the stator of the screw pump to rotate to start the well lifting. After the crude oil in the well is lifted into the next lifting module, the monitoring device of the lifting module detects the first pressure and transmits the first pressure to the control cabinet. The control cabinet controls the motor of the lifting module where the monitoring device is located to work based on the received first pressure, so as to achieve continuous lifting of the oil well through the lifting module. Based on the pressure monitored by each monitoring device, the control cabinet sequentially controls the motors in the corresponding lifting modules of each monitoring device to start working from bottom to top, until the motor of the lifting module at the top of the rodless lifting string starts working, so as to achieve oil well lifting through the entire rodless lifting string.

11. The application of a rodless lifting string as described in any one of claims 1-6 and a rodless lifting system as described in any one of claims 7-9 in the field of oil and gas exploration and development technology.

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