Heavy oil horizontal well separate recovery pipe column and control method

Abstract

The invention provides a heavy oil horizontal well segmented oil extraction pipe column and a control method, and belongs to the technical field of oil extraction. Specifically, a part which extends to the position below the second limiting piston and is in sliding sealing fit with the first limiting piston is additionally arranged on the first cylinder sleeve part of the inner cylinder sleeve, and a second opening is creatively formed in the part, so that the part and the second opening are combined together to form the separate recovery pipe column for the heavy oil horizontal well. The on-off state between the first opening and the third opening is controlled; meanwhile, according to the thick oil horizontal well separate recovery pipe column, the electric push rod directly pushes the inner cylinder sleeve, the second opening is switched between the on-off position, and the situation that metal materials of the center pipe, the inner cylinder sleeve and the outer cylinder sleeve interfere with actions of electromagnetic materials is avoided. Therefore, the thick oil horizontal well separate recovery pipe column has the advantages of being reliable and accurate in control action.

Description

Technical Field

[0001] The invention relates to the technical field of oil production, and in particular to a heavy oil horizontal well segmented production pipe string and a control method thereof. Background Art

[0002] In order to solve the problem of failure of control and mis-opening of the electric control distributor in the ball-throwing electric control sub-production, some existing sub-production tools use a hydraulically controlled sealing mechanism and an electric control oil inlet mechanism that are connected to the lumen of the oil production pipe through the same flow hole, and perform opening and closing control according to the flow direction and pressure of the fluid in the flow hole to achieve control of the oil production status of the sub-production section. However, the test oil field production practice shows that the above sub-production tools still have the following defects:

[0003] 1. Affected by the iron material of the oil production pipe, during the magnetic pole conversion process of the magnet, the magnetization of the oil production pipe is likely to cause the switch action to fail, or at least cause the reliability of the switch action to deteriorate;

[0004] 2. Affected by the high viscosity of crude oil in heavy oil wells, the fluid pressure change trend in the flow hole has a lag and poor accuracy, resulting in untimely and inaccurate switch control of the electronically controlled oil inlet mechanism.

[0005] In order to solve the above technical problems, a separation and production tool with high control accuracy is proposed to better serve the heavy oil production operation. Summary of the invention

[0006] In view of the above problems, the present invention is proposed to provide a heavy oil horizontal well segmented production tubing string and control method that overcome the above problems or at least partially solve the above problems, which can solve the problem of inaccurate switch action of the existing electric control oil inlet mechanism and achieve the purpose of improving the heavy oil production output.

[0007] Specifically, in a first aspect of the present invention, a heavy oil horizontal well production string is provided, comprising:

[0008] A central tube extending up and down, with a first opening formed on the tube wall of the central tube and a first limiting piston protruding below the central tube;

[0009] A sealing mechanism sleeved outside the central tube, the sealing mechanism comprising:

[0010] An inner cylinder sleeve, the inner cylinder sleeve comprising a first cylinder sleeve portion which is slidably and sealingly sleeved on the outside of the first limiting piston, and a second limiting piston which is stopped above the first limiting piston; wherein a second opening which is located below the second limiting piston is formed on the first cylinder sleeve portion, and a sealing stop which is always connected to the first opening is formed at the lower end of the second limiting piston;

[0011] An outer cylinder sleeve, wherein the outer cylinder sleeve has a second cylinder sleeve portion which is sleeved outside the first cylinder sleeve portion in a sliding and sealing manner, and a third opening is formed on the second cylinder sleeve portion and is located below the second opening;

[0012] The electric telescopic mechanism is fixed relative to the outside of the central tube and located above the second limiting piston. The electric telescopic mechanism is configured to push the second limiting piston downward when the sealing mechanism is in the sealing state, so as to cause the first opening, the second opening and the third opening to communicate with each other.

[0013] Furthermore, the electric telescopic mechanism comprises:

[0014] An electric push rod fixed relative to the outside of the central tube, the electric push rod includes a push rod for pushing the first limit piston downward;

[0015] A pressure sensor is fixed on the output end of the electric push rod, and the pressure sensor is configured to detect the abutment pressure between the push rod and the first limit piston in the up and down directions.

[0016] Furthermore, the electric telescopic mechanism also includes:

[0017] A position sensor is provided on the electric push rod, and the position sensor is configured to detect an extension amount of the push rod.

[0018] Furthermore, the setting mechanism further comprises:

[0019] A third limit piston is fixedly sleeved on the outside of the central tube, the third limit piston and the first cylinder sleeve are slidingly sealed and matched, and the third limit piston is stopped above the second limit piston; and,

[0020] The electric push rod also includes a casing fixed to the lower end of the third limiting piston, the upper end of the push rod is reciprocatingly arranged up and down in the casing, and the lower end of the push rod forms an upper tooth inclined upward; and a connecting blind hole opening upward and used to cooperate with the lower end sleeve of the push rod is formed at the upper end of the second limiting piston, and lower teeth inclined downward and used to engage with the upper teeth are formed on the hole wall of the connecting blind hole.

[0021] Further, the central tube includes an upper tube section and a lower tube section fixedly sleeved at its lower end, the first limiting piston sleeved outside the upper tube section and a limiting step spaced from the inside and outside of the first cylinder sleeve and sleeved outside the upper tube section are formed at the upper end of the lower tube section; and,

[0022] The first opening and the second opening are both adjacent to the first limiting piston in upper and lower directions, and when the setting mechanism completes the setting, the third opening is arranged opposite to the first opening in the inner and outer sides.

[0023] In a second aspect of the present invention, a control method for a heavy oil horizontal well production string is provided, comprising:

[0024] After the well is completed, the above-mentioned heavy oil horizontal well production string is lowered into the wellbore;

[0025] Injecting a packer fluid into the heavy oil horizontal well production string;

[0026] After the packer fluid is continuously injected for a first set time, the electric push rod of the heavy oil horizontal well production string is started to push the inner cylinder sleeve of the heavy oil horizontal well production string downward, thereby making the first opening, the second opening and the third opening of the heavy oil horizontal well production string communicate with each other;

[0027] When the extension amount of the electric telescopic mechanism reaches a set threshold, the heavy oil horizontal well production string is controlled to start the oil pumping operation.

[0028] Furthermore, during the first set time of continuously injecting the packing fluid, the method further comprises:

[0029] Acquire a set time within the first set time, and a wellhead pressure of the packer fluid at the wellhead in the heavy oil horizontal well production string;

[0030] At or before the set time, gradually increasing the injection flow rate of the packer fluid from a first set flow rate according to a first set speed, so as to accelerate the increase of the wellhead pressure;

[0031] After the set time, the injection flow rate of the packer fluid is gradually reduced according to a second set speed to cause the wellhead pressure to increase at a reduced speed;

[0032] When the first set time is reached and the top pressure measured by the pressure sensor in the heavy oil horizontal well production string is less than the minimum value of the preset first pressure threshold, the sealing fluid is continuously injected into the heavy oil horizontal well production string at a second set flow rate that is smaller than the first set flow rate until the low pressure is within the range of the first pressure threshold; and a first correction time is obtained within the first set time and is located after the set time by a set interval, and then the first correction time is used as the set time of another heavy oil horizontal well production string used later.

[0033] Further, after obtaining the set time and the wellhead pressure, the method further includes:

[0034] In the case where the top pressure reaches the first pressure threshold within the first set time, the injection of the sealing fluid is stopped; and a second corrected time is obtained within the first set time and before the set time by the set interval length, and the second corrected time is then used as the set time of another heavy oil horizontal well production string used later.

[0035] Furthermore, after starting the electric push rod of the heavy oil horizontal well production string, the method further comprises:

[0036] Controlling the push rod of the electric push rod of the heavy oil horizontal well production string to reciprocate and extend at a uniform speed until, when the push rod returns to an initial state, the top pressure measured by the pressure sensor of the heavy oil horizontal well production string is less than a second pressure threshold;

[0037] Obtaining the push rod's top pressure measured by the pressure sensor at each extension amount of the extension stroke;

[0038] Determine the elongation when the increasing speed of the push rod pressure suddenly decreases from the initial state of the push rod, and record it as the minimum opening elongation;

[0039] Determine the elongation when the increase rate of the push rod pressure is the smallest from the initial state of the push rod, and record it as the maximum opening elongation;

[0040] In the case of the oil pumping operation, the extension amount of the push rod is adjusted between the maximum opening extension amount and the minimum opening extension amount according to the target flow rate required for the oil pumping operation.

[0041] Furthermore, after controlling the heavy oil horizontal well production string to start the oil extraction operation, the method further includes:

[0042] During a second set time, the extension of the push rod is maintained between the maximum opening extension and the minimum opening extension;

[0043] After the second set time, within a third set time, the push rod is placed at the maximum opening extension, and it is determined whether the push pressure is reduced within the third set time.

[0044] If not, the set time is increased on the basis of the second set time to obtain the revised second set time, and the revised second set time is used as the second set time for the next oil pumping operation.

[0045] The beneficial effects of the present invention are:

[0046] The heavy oil horizontal well production string of the present invention adds a part extending to the bottom of the second limit piston and slidingly sealingly cooperating with the first limit piston on the first cylinder sleeve part of the inner cylinder sleeve, and creatively opens a second opening on the part, so that the part and the second opening together control the on-off state between the first opening and the third opening; at the same time, the heavy oil horizontal well production string of the present invention directly pushes the inner cylinder sleeve by an electric push rod, and the second opening switches between the on-off positions, so as to prevent the metal materials of the central pipe, the inner cylinder sleeve and the outer cylinder sleeve from interfering with the action of the electromagnetic material. Therefore, the heavy oil horizontal well production string of the present invention has the advantages of reliable and accurate control action.

[0047] Preferably, the heavy oil horizontal well separation pipe string of the present invention collects the top pressure between the electric push rod and the inner cylinder sleeve, indirectly obtains the sealing pressure of the sealing fluid in the annular cavity between the inner cylinder sleeve and the central tube, and controls the increasing speed of the sealing pressure by the filling time of the sealing fluid, so as to reduce the top pressure applied to the electric push rod when the second limit piston rises to the final stage, so as to avoid overload damage to the pressure sensor, thereby ensuring the accuracy of the detection result of the pressure sensor in subsequent detection. Therefore, the heavy oil horizontal well separation pipe string of the present invention has the advantages of protecting sensitive components and accurate detection results.

[0048] Preferably, the heavy oil horizontal well production string of the present invention combines a pressure sensor and a displacement sensor on the electric push rod to obtain the minimum opening telescopic amount of the push rod when the second opening is in the minimum connection state between the first opening and the third opening, and the maximum opening telescopic amount of the push rod when the second opening is in the maximum connection state between the first opening and the third opening, and thereby control the telescopic rod, and more accurately control the opening of the oil production port of the heavy oil horizontal well production string of the present invention in the oil layer. Therefore, the heavy oil horizontal well production string of the present invention has the advantage of accurate opening control.

[0049] Based on the following detailed description of specific embodiments of the present invention in conjunction with the accompanying drawings, those skilled in the art will become more aware of the above and other objects, advantages and features of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0050] Hereinafter, some specific embodiments of the present invention will be described in detail in an exemplary and non-limiting manner with reference to the accompanying drawings. The same reference numerals in the accompanying drawings indicate the same or similar components or parts. It should be understood by those skilled in the art that these drawings are not necessarily drawn to scale. In the accompanying drawings:

[0051] Figure 1 is a schematic structural diagram of a heavy oil horizontal well production string according to an embodiment of the present invention;

[0052] Figure 2 yes Figure 1Schematic diagram of the functional part of the oil production section of the medium-heavy oil horizontal well production string in the initial state;

[0053] Figure 3 yes Figure 2 A partial enlarged view of the middle part;

[0054] Figure 4 yes Figure 1 Schematic diagram of the functional part of the oil production section of the medium-heavy oil horizontal well production string after the completion of the setting seal;

[0055] Figure 5 yes Figure 4 A partial enlarged view of point B in the middle;

[0056] Figure 6 yes Figure 1 Schematic diagram of the functional part of the oil production section of the medium-heavy oil horizontal well production string under oil production status;

[0057] Figure 7 yes Figure 6 A partial enlarged view of point C in the middle;

[0058] Figure 8 is a flow chart of a control method for a heavy oil horizontal well production string according to an embodiment of the present invention;

[0059] Fig. 9 is based on Figure 8 A flow chart of a control method for controlling the packing fluid using a set time;

[0060] Fig.10 is based on Figure 8 A flow chart of another control method for controlling the packing fluid using a set time;

[0061] Fig.11 is based on Figure 8 The control method is a flow chart of the control method for the extension of the push rod;

[0062] Fig.12 is based on Fig.11 A flow chart of a control method for controlling an oil pumping operation using a second set time.

[0063] in:

[0064] 110- sucker rod, 120- coupling, 130- oil pump, 140- anchor packer, 150- first oil production section, 160- second oil production section, 170- plugging device, 180- main control equipment;

[0065] 200-central tube, 210-first opening, 220-first limiting piston, 230-upper tube section, 240-lower tube section, 241-limiting step;

[0066] 300-sealing mechanism, 310-inner cylinder sleeve, 311-first cylinder sleeve part, 312-second limiting piston, 313-sealing stop, 314-second opening, 315-connecting blind hole, 316-lower teeth, 320-outer cylinder sleeve, 321-second cylinder sleeve part, 322-third opening, 330-electric telescopic mechanism, 331-electric push rod, 332-push rod, 333-sealing cap, 334-pressure sensor, 335-housing, 336-upper teeth, 340-third limiting piston. DETAILED DESCRIPTION

[0067] In the description of the embodiments of the present invention, it should be understood that the terms "first" and "second" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features, that is, include one or more of the features. In the description of the present invention, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined. When a feature "includes or contains" one or some of the features it covers, unless otherwise specifically described, this indicates that other features are not excluded and may further include other features.

[0068] Unless otherwise clearly defined and limited, the terms "set", "install", "connect", "connect", "fix", "couple" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral one; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. A person skilled in the art should be able to understand the specific meanings of the above terms in the present invention according to the specific circumstances.

[0069] In addition, in the description of this embodiment, the first feature being "above" or "below" the second feature may include the first and second features being in direct contact, or may include the first and second features not being in direct contact but being in contact through another feature between them. That is, in the description of this embodiment, the first feature being "above", "above", and "above" the second feature includes the first feature being directly above and obliquely above the second feature, or simply indicates that the first feature is higher in level than the second feature. The first feature being "below", "below", or "below" the second feature may mean that the first feature is directly below or obliquely below the second feature, or simply indicates that the first feature is lower in level than the second feature.

[0070] In the description of the present embodiment, the description with reference to the terms "one embodiment", "some embodiments", "illustrative embodiments", "examples", "specific examples", or "some examples" means that the specific features, structures, materials, or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described may be combined in any one or more embodiments or examples in a suitable manner.

[0071] like Figure 1 As shown, the heavy oil horizontal well segmented production string of the present invention includes a sucker rod 110, a coupling 120, a pump 130, an anchor packer 140, a first production section 150, a second production section 160 and a plug 170 connected in sequence from top to bottom, wherein the first production section 150 and the second production section 160 use the same structure of the isolation-production integrated mechanism, and the first production section 150 and the second production section 160 are both located in the horizontal section of the wellbore. At the same time, the heavy oil horizontal well segmented production string of the present invention also includes a main control device 180, which is placed on the well and connected to various controlled devices (such as sensors, electric push rods, etc.) downhole via cables. Of course, the main inventive concept of the heavy oil horizontal well segmented production string of the present invention is aimed at the isolation-production integrated mechanism as the first production section 150 and the second production section 160, and its specific structure is described in detail below.

[0072] like Figure 2 and Figure 3The isolation-production allocation integrated mechanism includes a central tube 200 extending up and down and a sealing mechanism 300 sleeved on the outside of the central tube 200. A first opening 210 and a first limiting piston 220 protruding below the central tube 200 are formed on the tube wall of the central tube 200. The sealing mechanism 300 includes an inner cylinder sleeve 310 and an outer cylinder sleeve 320, wherein the inner cylinder sleeve 310 has a first cylinder sleeve portion 311 sleeved on the outside of the first limiting piston 220 in a sliding and sealing manner, and a second limiting piston 312 blocked above the first limiting piston 220; wherein a second opening 314 located below the second limiting piston 312 is formed on the first cylinder sleeve portion 311, and a sealing stop 313 always connected to the first opening 210 is formed at the lower end of the second limiting piston 312; the outer cylinder sleeve 320 has a second cylinder sleeve portion 321 sleeved on the outside of the first cylinder sleeve portion 311 in a sliding and sealing manner, and a third opening 322 located below the second opening 314 is formed on the second cylinder sleeve portion 321. The integrated isolation and production allocation mechanism also includes an electric telescopic mechanism 330 relatively fixed outside the central pipe 200 and located above the second limiting piston 312. The electric telescopic mechanism 330 is configured to push the second limiting piston 312 downward when the sealing mechanism 300 is in the sealing state, so as to cause the first opening 210, the second opening 314 and the third opening 322 to communicate with each other. As some preferred embodiments of the heavy oil horizontal well segmented production pipe of the present invention, in order for the crude oil to smoothly enter the central pipe 200 during the pumping operation stage, the opening area of ​​the second opening 314 should generally be larger than the first opening 210 and the third opening 322, and the opening areas of the first opening 210 and the third opening 322 may be equal or unequal; and in the case where the opening areas of the first opening 210 and the third opening 322 are unequal, it is preferred that the opening area of ​​the first opening 210 is larger than the opening area of ​​the third opening 322, so that it is convenient for the crude oil to enter the central pipe 200, and it is also ensured that the pressure division efficiency of each production section is relatively high when the central pipe 200 is pressurized and sealed.

[0073] Based on the embodiment of the heavy oil horizontal well segmented production pipe of the present invention, as shown in FIG. Figure 8 As shown, when controlling the heavy oil horizontal well segmented production pipe string of the present invention to perform oil production operation, the following steps are included:

[0074] S100, after the well is completed, a heavy oil horizontal well production string is lowered into the wellbore;

[0075] S200, injecting packer fluid into the heavy oil horizontal well production string;

[0076] S300, after continuously injecting the packer fluid for a first set time, starting the electric push rod of the heavy oil horizontal well production string to push the inner cylinder sleeve 310 of the heavy oil horizontal well production string downward, thereby making the first opening 210, the second opening 314 and the third opening 322 of the heavy oil horizontal well production string communicate with each other;

[0077] S400, when the extension amount of the electric telescopic mechanism reaches a set threshold, the heavy oil horizontal well production string is controlled to start the oil pumping operation.

[0078] In the above step S300, the first set time is to ensure the pressure time of the hydraulic setting of the sealing mechanism, that is, the basic idea of ​​controlling the hydraulic setting state by the first set time is to use a timer or an automatic control system to adjust the pressure and flow of the hydraulic system. This is common knowledge in the art. For example, in some embodiments, the method of using the first set time to control the setting can use the following steps:

[0079] S311, Sensors and Detection: Install pressure, position and other sensors to monitor the hydraulic setting status in real time.

[0080] S312, control system: configure a PLC (programmable logic controller) or other control device to receive and process sensor data.

[0081] S313, timing setting: setting time parameters in the control system to determine the time interval between closing and opening of the seat.

[0082] S314, actuator: connects the hydraulic pump and valve, and adjusts the hydraulic pressure through the control system to make the sealing in different states within the set time.

[0083] S315, safety mechanism: add timeout alarm and fault diagnosis functions to ensure safe and reliable system operation.

[0084] S316, Test and Adjust: Test the system and adjust parameters according to actual conditions to achieve the expected results.

[0085] This method can achieve precise hydraulic setting control and improve operational efficiency and safety. The following are some timing reference values ​​in common applications: usually between 10 and 20 minutes, depending on the equipment requirements. For example, in some efficient use scenarios, it may be 12-15 minutes.

[0086] Based on this, in the heavy oil horizontal well production string of the present invention, a portion extending to the bottom of the second limit piston 312 and slidingly sealingly cooperating with the first limit piston 220 is added to the first cylinder sleeve portion 311 of the inner cylinder sleeve 310, and a second opening 314 is creatively opened on the portion, so that the on-off state between the first opening 210 and the third opening 322 is controlled by the portion and the second opening 314 together; at the same time, the heavy oil horizontal well production string of the present invention directly pushes the inner cylinder sleeve 310 by an electric push rod, and the second opening 314 switches between the on-off positions, so as to prevent the metal material of the central pipe 200, the inner cylinder sleeve 310 and the outer cylinder sleeve 320 from interfering with the action of the electromagnetic material. Therefore, the heavy oil horizontal well production string of the present invention has the advantages of reliable and accurate control action.

[0087] In some preferred embodiments of the invention of heavy oil horizontal well production string, as Figure 3 As shown, the electric telescopic mechanism 330 includes an electric push rod 331 relatively fixed outside the central tube 200, and a pressure sensor 334 fixed on the output end of the electric push rod 331. The electric push rod 331 includes a push rod 332 for pushing the first limit piston 220 downward. The pressure sensor 334 is configured to detect the push rod 332 and the first limit piston 220 in the up and down directions. As a further optimization of some preferred embodiments, in order to avoid contamination of the pressure sensor 334 by the leakage of the packing fluid and crude oil, the electric push rod 331 may also include a sealing cap 333 slidably and sealedly sleeved on the output end of the push rod 332, and the pressure sensor 334 is placed between the cap portion of the sealing cap 333 and the rod end of the push rod 332, so that when the sealing cap 333 slides upward relative to the push rod 332, the cap portion of the sealing cap 333 will squeeze the pressure sensor 334 located on the rod end of the push rod 332 to measure the corresponding push pressure.

[0088] Based on the electric push rod 331 in some preferred embodiments, in addition to continuing to perform the oil pumping operation according to the above steps S310-340, as some preferred embodiments of the control method of the heavy oil horizontal well production string of the present invention, as shown in FIG. Fig. 9 As shown, the control method of the heavy oil horizontal well production string may further include the following steps in step S300 during the first set time of continuously injecting the packing fluid:

[0089] S321, obtaining a set time within the first set time and a wellhead pressure of the packer fluid in the heavy oil horizontal well production string at the wellhead;

[0090] S322, at or before the set time, gradually increasing the injection flow rate of the packer fluid from the first set flow rate according to the first set speed, so as to accelerate the increase of the wellhead pressure;

[0091] S323, after the set time, gradually reducing the injection flow rate of the packer fluid according to the second set speed to cause the wellhead pressure to increase at a reduced speed;

[0092] S324, when the first set time is reached and the top pressure measured by the pressure sensor 334 in the heavy oil horizontal well production string is less than the minimum value of the preset first pressure threshold, the sealing fluid is continuously injected into the heavy oil horizontal well production string at a second set flow rate that is smaller than the first set flow rate until the low pressure is within the range of the first pressure threshold; and a first correction time is obtained that is within the first set time and is located after the set time by a set interval, and then the first correction time is used as the setting time of another heavy oil horizontal well production string used later.

[0093] In the above steps S321-S324, the initial value of the set time at the factory is generally configured as the middle value of the first set time. For example, when the first set time is 12 minutes, the set time is configured as the 6th minute at the factory. In the application of hydraulic setting, the injection flow rate of the sealing fluid may range from 0.1 to 1.0L / min (liters / min), but the specific flow rate should be determined through experiments based on your equipment and process. For example, 0.5L / min is the first set flow rate and 0.1L / min is the first set speed, so that the injection flow rate reaches 1.0L / min at the 6th minute, and then the flow rate is reduced according to the second set speed; for another example, when the second set speed is also 0.1L / min, the injection flow rate is reduced to 0.5L / min at the 12th minute; for another example, when the second set speed is 0.2L / min, the injection flow rate is reduced to 0.2L / min at the 12th minute. Therefore, in order to further reduce the squeezing damage of the packing fluid to the pressure sensor 334, as a further preferred embodiment of the control method of the heavy oil horizontal well production string of the present invention, the second set speed should be greater than the first set speed.

[0094] Furthermore, the first pressure threshold should be less than the upper threshold value (which can be a specific value, such as 350 bar, or a value range, such as 200-700 bar) for the normal operation of the pressure sensor 334 to ensure the normal operation of the pressure sensor 334. For example, the pressure sensor 334 can be selected from some pressure sensor 334 series of Wika, which may provide a 700 bar model at any time.

[0095] Furthermore, to avoid overcorrection and squeeze damage to the pressure sensor 334, the interval time is generally set to any value between 0.5 and 1 minute. For example, when the interval time is set to 0.5 minutes and the set time is the 6th minute, the first correction time should be the 6.5th minute.

[0096] like Fig.10 As shown in the figure, as other preferred embodiments of the control method of the heavy oil horizontal well production string of the present invention, in order to avoid the situation that the pressure sensor 334 is pressed too early due to the first set flow rate being too large in S321, the control method of the heavy oil horizontal well production string can also include the following steps after step S321:

[0097] S325, when the top pressure reaches the first pressure threshold within the first set time, stop injecting the packing fluid; and obtain a second correction time within the first set time and before the set time by the set interval time, and then use the second correction time as the setting time of another heavy oil horizontal well production string used later. For example, when the set interval time is 0.5min and the set time is the 6th minute, the second correction time should be the 5.5th minute.

[0098] Based on this, the heavy oil horizontal well production string of the present invention collects the top pressure between the electric push rod 331 and the inner cylinder sleeve 310, indirectly obtains the sealing pressure of the sealing fluid in the annular cavity between the inner cylinder sleeve 310 and the central tube 200, and controls the increasing speed of the sealing pressure by the filling time of the sealing fluid. On the one hand, the injection of the sealing fluid is accelerated in the early stage of the sealing, and on the other hand, when the sealing is about to be completed, the top pressure applied to the electric push rod 331 by the second limit piston 312 in the final stage of rising can be reduced to avoid overload damage to the pressure sensor 334, thereby ensuring that the pressure sensor 334 has accurate detection results in subsequent detections. Therefore, the heavy oil horizontal well production string of the present invention has the advantages of protecting sensitive components and accurate detection results. Based on this advantage, when using the top pressure to indirectly detect the oil pressure of the crude oil entering the central tube 200 through the first opening 210, the second opening 314 and the third opening 322 in sequence, the pressure sensor 334 will not have a large error due to the accumulated damage in the sealing stage, thereby improving the accuracy of the pumping operation stage.

[0099] In some preferred embodiments of the heavy oil horizontal well production string of the present invention, the electric telescopic mechanism 330 further includes a position sensor (not shown) arranged on the electric push rod 331, and the position sensor is configured to detect the extension amount of the push rod 332. As is known to all, the technical means for detecting the position of the push rod 332 on the electric push rod 331 generally include the following:

[0100] 1) Encoder: An encoder is installed on the push rod 332 of the electromagnetic push rod 332, and the position of the push rod 332 is determined by detecting the signal of the encoder. The encoder can be an absolute encoder that can directly read the exact position of the push rod 332, or an incremental encoder that measures the relative displacement of the push rod 332.

[0101] 2) Displacement sensor: A displacement sensor such as a magnetoresistor, a Hall sensor, or a photoelectric sensor is used, which is installed on the electromagnetic push rod 332 or connected to the push rod 332, and the position of the push rod 332 is determined by monitoring the change of the output signal of the sensor.

[0102] 3) Pressure sensor 334: The pressure sensor 334 installed on the electromagnetic push rod 332 can detect the magnitude of the thrust, thereby indirectly determining the position of the push rod 332. According to the change of the output value of the pressure sensor 334, the position information of the push rod 332 can be inferred.

[0103] 4) Limit switch: limit switches are set at both ends of the travel of the electromagnetic push rod 332. When the push rod 332 touches the limit switch, the switch will be triggered, indicating that the push rod 332 has reached the corresponding position. The position of the push rod 332 is determined by monitoring the state of the limit switch.

[0104] 5) Laser rangefinder: In some high-precision applications, a laser rangefinder may be used to monitor the position of the push rod 332. The laser rangefinder can provide high-precision distance measurement and can monitor the position of the push rod 332 in real time.

[0105] These methods can be used alone or in combination to ensure accurate determination of the position of the electromagnetic push rod 332. The selection of the appropriate detection method depends on the requirements, accuracy and reliability of the specific application.

[0106] Further, as some further preferred embodiments of the heavy oil horizontal well production string of the present invention, the displacement sensor in the heavy oil horizontal well production string of the present invention can be in the form of an encoder (that is, the displacement sensor not only has the function of detecting the displacement of the push rod 332, but also can control the power of the electromagnetic push rod 332.), or can also be an existing displacement sensor, or even a pressure sensor 334, a limit switch, a laser rangefinder, etc. Based on this, the position sensor in the heavy oil horizontal well production string of the present invention is a functional limitation, which indicates that as long as the function of position detection can be realized on the electromagnetic push rod 332, it should belong to the protection scope covered by the electromagnetic push rod 332 of the heavy oil horizontal well production string of the present invention.

[0107] Based on the displacement sensor in some preferred embodiments, in addition to continuing to perform the oil pumping operation according to the above steps S310-340, as some preferred embodiments of the control method of the heavy oil horizontal well production string of the present invention, as shown in FIG. Fig.11 As shown, the control method of the heavy oil horizontal well production string may further include the following steps after starting the electric push rod 331 of the heavy oil horizontal well production string in S200:

[0108] S210, controlling the push rod 332 of the electric push rod 331 to reciprocate and extend at a uniform speed until the push rod 332 returns to the initial state and the abutting pressure measured by the pressure sensor 334 is less than a second pressure threshold;

[0109] S220, obtaining the top pressure of the push rod 332 measured by the pressure sensor 334 at each extension amount of the extension stroke;

[0110] S230, determining the elongation when the increasing speed of the push rod 332 suddenly decreases from the initial state, and recording it as the minimum opening elongation;

[0111] S240, determining the elongation of the push rod 332 when the increasing speed of the push pressure is the smallest from the initial state, and recording it as the maximum opening elongation;

[0112] S250, when performing an oil pumping operation, the extension amount of the push rod 332 is adjusted between the maximum opening extension amount and the minimum opening extension amount according to the target flow rate required for the oil pumping operation.

[0113] In the above step S230, when the push rod 332 begins to extend, the first opening 210 and the third opening 322 are separated by the first cylinder sleeve portion 311 of the inner cylinder sleeve 310, so that the sealing fluid in the annulus between the inner cylinder sleeve 310 and the center pipe 200 is squeezed, the pressure increases, and the corresponding push pressure acting on the pressure sensor 334 will also increase accordingly. As the push rod 332 continues to extend, the sealing pressure of the sealing fluid in the annulus will also continue to increase synchronously; as the inner cylinder sleeve 310 descends to a position where the second opening 314 gradually connects to the first opening 210 and the second opening 314, the sealing fluid in the annulus can be discharged from the first opening 210 to the outside, which causes the increase rate of the push pressure to decrease suddenly; until the second opening 314 completely connects the first opening 210 and the third opening 322, the speed at which the sealing fluid leaks out of the first opening 210 reaches the maximum, and the corresponding increase rate of the push pressure reaches the minimum (even to the point of decompression, which can be understood as a negative increase rate).

[0114] Based on this, the heavy oil horizontal well production string of the present invention combines the pressure sensor 334 and the displacement sensor on the electric push rod 331 to obtain the minimum opening telescopic amount of the push rod 332 when the second opening 314 is in the minimum connection state between the first opening 210 and the third opening 322, and the maximum opening telescopic amount of the push rod 332 when the second opening 314 is in the maximum connection state between the first opening 210 and the third opening 322, and thereby control the telescopic rod, and more accurately control the opening of the oil production port of the heavy oil horizontal well production string of the present invention in the oil layer. Therefore, the heavy oil horizontal well production string of the present invention has the advantage of accurate opening control.

[0115] As a further preferred embodiment of the heavy oil horizontal well production string of the present invention, in order to realize multiple oil pumping operations with stratified production, when the maximum opening extension and the minimum length extension are obtained, in each oil pumping operation, it is necessary to first open the first opening 210 according to the needs of the oil pumping operation; then close the first opening 210 after completing one oil pumping operation; then maintain pressure / slowly release for a period of time, and then open the first opening 210 again for the next oil pumping operation. To this end, if Fig.12 As shown, after the above step S300, the heavy oil horizontal well production string of the present invention may further include the following steps:

[0116] S410, maintaining the extension of the push rod 332 between the maximum opening extension and the minimum opening extension within a second set time;

[0117] S420, after the second set time, within a third set time, the push rod 332 is at the maximum opening extension, and it is determined whether the abutting pressure is reduced within the third set time,

[0118] S421, if it is not reduced, then increasing the set time on the basis of the second set time to obtain a revised second set time, and using the revised second set time as the second set time for the next oil pumping operation;

[0119] S422, if it decreases, the control push rod 332 is retracted to the initial state to cause the first opening 210 and the third opening 322 to be isolated.

[0120] In the above steps S410-420, the second set time is the set time for the heavy oil horizontal well production string of the present invention to complete a stratified production pumping operation. For example, the second set time can be set to 5 days or longer (for example, 30 days). In the above step S420, the third set time is a preset set time for detecting whether the crude oil injection amount of the pumping operation is still large under the maximum opening of the first opening 210. Its setting generally needs to be combined with the cycle of the second set time. For example, when the second set time is 5 days, the third set time can be set to 1 hour. In step S421, the setting time can be in days, that is, it can be 1 day, 2 days... For example, when the original second set time is 5 days, the top pressure does not decrease within the third set time, so the second set time can be corrected to 6 days. In this way, when the oil layer is pumped for the next time, a pumping operation will be performed according to the corrected second set time.

[0121] Based on this, the heavy oil horizontal well production string of the present invention realizes the technical effect of autonomous learning and self-correction of the production allocation and oil pumping operations of different oil layers in the stratified production allocation, so that the heavy oil horizontal well production string of the present invention can realize a more adaptable and personalized stratified production allocation plan according to the conditions of different oil layers.

[0122] As a further preferred embodiment of the heavy oil horizontal well production string of the present invention, Figure 3 , 5 As shown in , 7, the sealing mechanism 300 also includes a third limiting piston 340 fixedly sleeved on the outside of the central tube 200, the third limiting piston 340 and the first cylinder sleeve 311 are slidingly sealed and matched, and are stopped above the second limiting piston 312; and, the electric push rod 331 also includes a housing 335 fixed to the lower end of the third limiting piston 340, the upper end of the push rod 332 is reciprocatingly arranged in the housing 335, and an upper tooth 336 inclined upward is formed at its lower end; and, a connecting blind hole 315 is formed at the upper end of the second limiting piston 312, which is open upward and is used to cooperate with the lower end sleeve of the push rod 332, and a lower tooth 316 inclined downward and used to bite with the upper tooth 336 is formed on the hole wall of the connecting blind hole 315. By utilizing the mutual engagement between the upper teeth 336 and the lower teeth 316, the push rod 332 and the second limiting piston 312 can be more firmly combined together under the setting pressure, thereby ensuring the reliability and accuracy of the push and pull action of the push rod 332; at the same time, when the second limiting piston 312 is in the initial state, there is a distance between it and the electric push rod 331, and the upward movement of the second limiting piston 312 will not be restricted by the electric push rod 331 at the beginning, thus avoiding the problem of the second limiting piston 312 being unable to move due to a failure of the electric push rod 331, thereby ensuring the reliability of the hydraulic setting.

[0123] As a further preferred embodiment of the heavy oil horizontal well production string of the present invention, Figure 3 , 5As shown in FIG. 7 , the center tube 200 includes an upper tube section 230 and a lower tube section 240 fixedly sleeved at its lower end, a first limiting piston 220 sleeved outside the upper tube section 230 is formed at the upper end of the lower tube section 240, and a limiting step 241 is formed which is spaced apart from the first cylinder sleeve 311 and sleeved outside the upper tube section 230; and the first opening 210 and the second opening 314 are both adjacent to the first limiting piston 220 in the upper and lower parts, and when the setting mechanism 300 completes the setting, the third opening 322 is arranged opposite to the first opening 210 in the inner and outer parts. By using the relative distribution form of the first opening 210, the second opening 314 and the third opening 322, the distance of the first opening 210 and the second opening 314 moving up to the position for connecting to the third opening 322 can be minimized, which can be adapted to the setting mechanism 300 with a smaller movement range on the one hand, and on the other hand, it can ensure that the first opening 210 and the second opening 314 can be reliably connected to the third opening 322.

[0124] At this point, those skilled in the art should recognize that, although multiple exemplary embodiments of the present invention have been shown and described in detail herein, many other variations or modifications that conform to the principles of the present invention can still be directly determined or derived based on the content disclosed in the present invention without departing from the spirit and scope of the present invention. Therefore, the scope of the present invention should be understood and recognized as covering all these other variations or modifications.

Claims

1. A heavy oil horizontal well production string, characterized in that: include: A central tube extending up and down, with a first opening formed on the tube wall of the central tube and a first limiting piston protruding below the central tube; A sealing mechanism sleeved outside the central tube, the sealing mechanism comprising: An inner cylinder sleeve, the inner cylinder sleeve comprising a first cylinder sleeve portion which is slidably and sealingly sleeved on the outside of the first limiting piston, and a second limiting piston which is stopped above the first limiting piston; wherein a second opening which is located below the second limiting piston is formed on the first cylinder sleeve portion, and a sealing stop which is always connected to the first opening is formed at the lower end of the second limiting piston; An outer cylinder sleeve, wherein the outer cylinder sleeve has a second cylinder sleeve portion which is sleeved outside the first cylinder sleeve portion in a sliding and sealing manner, and a third opening is formed on the second cylinder sleeve portion and is located below the second opening; The electric telescopic mechanism is fixed relative to the outside of the central tube and located above the second limiting piston. The electric telescopic mechanism is configured to push the second limiting piston downward when the sealing mechanism is in the sealing state, so as to cause the first opening, the second opening and the third opening to communicate with each other.

2. The heavy oil horizontal well production string according to claim 1, characterized in that: The electric telescopic mechanism comprises: An electric push rod fixed relative to the outside of the central tube, the electric push rod includes a push rod for pushing the first limit piston downward; A pressure sensor is fixed on the output end of the electric push rod, and the pressure sensor is configured to detect the abutment pressure between the push rod and the first limit piston in the up and down directions.

3. The heavy oil horizontal well production string according to claim 2, characterized in that: The electric telescopic mechanism also includes: A position sensor is provided on the electric push rod, and the position sensor is configured to detect an extension amount of the push rod.

4. The heavy oil horizontal well production string according to claim 2, characterized in that: The sealing mechanism further comprises: A third limit piston is fixedly sleeved on the outside of the central tube, the third limit piston and the first cylinder sleeve are slidingly sealed and matched, and the third limit piston is stopped above the second limit piston; and, The electric push rod also includes a casing fixed to the lower end of the third limiting piston, the upper end of the push rod is reciprocatingly arranged up and down in the casing, and the lower end thereof forms an upper tooth inclined upward; and, a connecting blind hole opening upward and used to cooperate with the lower end sleeve of the push rod is formed at the upper end of the second limiting piston, and lower teeth inclined downward and used to mesh with the upper teeth are formed on the hole wall of the connecting blind hole.

5. The heavy oil horizontal well production string according to claim 1, characterized in that: The central tube includes an upper tube section and a lower tube section fixedly sleeved at its lower end, the first limiting piston sleeved outside the upper tube section and a limiting step spaced from the inside and outside of the first cylinder sleeve and sleeved outside the upper tube section are formed at the upper end of the lower tube section; and The first opening and the second opening are both adjacent to the first limiting piston in upper and lower directions, and when the setting mechanism completes the setting, the third opening is arranged opposite to the first opening in the inner and outer sides.

6. A control method for a heavy oil horizontal well production string, characterized in that: include: After the well is completed, a heavy oil horizontal well production string as described in any one of claims 1 to 5 is lowered into the wellbore; Injecting a packer fluid into the heavy oil horizontal well production string; After the packer fluid is continuously injected for a first set time, the electric push rod of the heavy oil horizontal well production string is started to push the inner cylinder sleeve of the heavy oil horizontal well production string downward, thereby making the first opening, the second opening and the third opening of the heavy oil horizontal well production string communicate with each other; When the extension amount of the electric telescopic mechanism reaches a set threshold, the heavy oil horizontal well production string is controlled to start the oil pumping operation.

7. The control method according to claim 6, characterized in that: When the heavy oil horizontal well production string as claimed in claim 2 is lowered into the wellbore, during the first set time of continuously injecting the packer fluid, the method further comprises: Acquire a set time within the first set time, and a wellhead pressure of the packer fluid at the wellhead in the heavy oil horizontal well production string; At or before the set time, gradually increasing the injection flow rate of the packer fluid from a first set flow rate according to a first set speed, so as to accelerate the increase of the wellhead pressure; After the set time, the injection flow rate of the packer fluid is gradually reduced according to a second set speed to cause the wellhead pressure to increase at a reduced speed; When the first set time is reached and the top pressure measured by the pressure sensor in the heavy oil horizontal well production string is less than a preset first pressure threshold, the sealing fluid is continuously injected into the heavy oil horizontal well production string at a second set flow rate that is smaller than the first set flow rate until the top pressure reaches the first pressure threshold; and a first correction time is obtained within the first set time and is located after the set time by a set interval, and then the first correction time is used as the set time of another heavy oil horizontal well production string used later.

8. The control method according to claim 7, characterized in that: After obtaining the set time and the wellhead pressure, the method further includes: In the case where the top pressure reaches the first pressure threshold within the first set time, the injection of the sealing fluid is stopped; and a second corrected time is obtained within the first set time and before the set time by the set interval length, and the second corrected time is then used as the set time of another heavy oil horizontal well production string used later.

9. The control method according to claim 6, characterized in that: When the heavy oil horizontal well production string as claimed in claim 3 is lowered into the wellbore, after the electric push rod of the heavy oil horizontal well production string is started, the method further comprises: Controlling the push rod of the electric push rod of the heavy oil horizontal well production string to reciprocate and extend at a uniform speed until the push rod returns to an initial state and the top pressure measured by the pressure sensor of the heavy oil horizontal well production string is less than a second pressure threshold; Obtaining the push rod's top pressure measured by the pressure sensor at each extension amount of the extension stroke; Determine the elongation when the increasing speed of the push rod pressure suddenly decreases from the initial state of the push rod, and record it as the minimum opening elongation; Determine the elongation from the initial state of the push rod when the increasing speed of the push pressure is the smallest, and record it as the maximum opening elongation; When the oil pumping operation is performed, the extension amount of the push rod is adjusted between the maximum opening extension amount and the minimum opening extension amount according to a target flow rate required for the oil pumping operation.

10. The control method according to claim 9, characterized in that: After controlling the heavy oil horizontal well production string to start the oil pumping operation, the method further includes: During a second set time, the extension of the push rod is maintained between the maximum opening extension and the minimum opening extension; within a third set time after the second set time, the push rod is in the maximum opening extension, and it is determined whether the push pressure is reduced within the third set time, If not, the set time is increased on the basis of the second set time to obtain a revised second set time, and the revised second set time is used as the second set time for the next oil pumping operation.

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