Horizontal well intelligent segmented production process string and recovery method

Abstract

The application discloses a horizontal well intelligent segmented production process pipe column and a mining method.The process pipe column comprises an upper segment injection and production pipe column part, an intelligent production pipe column part and a lower segment oil pipe.The upper segment injection and production pipe column part comprises an upper segment oil pipe, a sucker rod and a sucker pump.The lower segment oil pipe is connected with a first packer at one end adjacent to the upper segment injection and production pipe column part.A plurality of downhole intelligent injection and production devices are arranged at intervals in the horizontal segment of the lower segment oil pipe.A second packer is arranged between two adjacent downhole intelligent injection and production devices to segment the horizontal well.The tail end of the lower segment oil pipe is connected with a screen pipe short section.The downhole intelligent injection and production device comprises an outer protection cylinder and an injection and production communication device.A center control component is arranged in the outer protection cylinder and the injection and production communication device.The center control component is used for layered injection and production monitoring and control.The application can realize different segment differentiated design of gas injection amount, and further realize balanced energy supplement, improves the maximum degree of reserve production of the whole segment of the horizontal well, and can realize remote gas injection amount optimization and adjustment in combination with parameter changes.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of enhanced oil recovery of low permeability reservoirs, and particularly relates to a horizontal well intelligent segmented huff and puff process pipe column and a mining method. BACKGROUND

[0002] At present, as the core technology for improving oil production rate and increasing the reserves to be produced, the horizontal well has become the main development well type and is applied in the ultra-low permeability-shale oil reservoirs. Influenced by the poor reservoir physical properties and the difficulty in establishing the displacement system, some ultra-low permeability reservoirs and shale oil reservoirs are developed by using natural energy, and no follow-up energy is supplemented after production. With the extension of the development time, the formation energy gradually decreases, the single well production declines greatly, which leads to the increase of the low-efficiency horizontal wells, and seriously restricts the ultimate recovery and economic benefits of the reservoir.

[0003] In recent years, with the continuous promotion of enhanced oil recovery technology, the enhanced oil recovery technology such as carbon dioxide flooding has developed rapidly, which provides a technical direction for the energy supplement of the tight reservoirs such as shale oil. Considering that the initial transformation scale of the tight reservoirs such as shale oil is large, the interwell channeling problem exists, and it is difficult to form an effective displacement process. At the same time, with the extension of the development time, the production contribution difference between the segments increases, and the energy difference between different segments is large.

[0004] Therefore, the present application is proposed by the present inventor on the basis of years of experience and practice in the relevant industry, so as to overcome the defects of the prior art. SUMMARY

[0005] The present application aims to provide a horizontal well intelligent segmented huff and puff process pipe column and a mining method, to realize the differentiated design of the gas injection volume of different segments, and then realize the balanced energy supplement, improve the maximum degree of reserves production of the horizontal well, and at the same time, combined with the parameter change, the remote gas injection volume optimization and adjustment can be realized.

[0006] The purpose of the present application is achieved by a horizontal well intelligent segmented huff and puff process pipe column, which comprises,

[0007] The upper segment injection and production pipe column part comprises an upper segment oil pipe, a sucker rod and an oil pump;

[0008] The intelligent huff and puff pipe column part comprises a lower segment oil pipe, one end of the lower segment oil pipe is connected with the upper segment injection and production pipe column part and is provided with a first packer; a plurality of downhole intelligent injection and production devices are arranged at intervals in the horizontal segment of the lower segment oil pipe, a second packer is arranged between two adjacent downhole intelligent injection and production devices to segment the horizontal well; a screen pipe nipple is connected to the tail end of the lower segment oil pipe; the downhole intelligent injection and production device comprises an outer sleeve and an injection and production communication device, a center control component is arranged in the outer sleeve and the injection and production communication device, and the center control component is used for monitoring and controlling the injection and production of different layers.

[0009] In a preferred embodiment of the present application, the central control component comprises a high-temperature battery, a control center unit, a pressure test component, an electrically controlled pressure balance gas nozzle, a small-diameter motor and a gas flow meter, the high-temperature battery is electrically connected with the control center unit, the pressure test component, the small-diameter motor and the gas flow meter are electrically connected with the control center unit in signal mode, the control center unit controls the small-diameter motor to adjust the opening degree of the electrically controlled pressure balance gas nozzle according to the pressure data collected by the pressure test component and the flow data collected by the gas flow meter, and the small-diameter motor adjusts the opening degree of the electrically controlled pressure balance gas nozzle to control the downhole flow in constant current mode.

[0010] In a preferred embodiment of the present application, the injection-production connecting device comprises a connecting device body cylinder in communication with the outer protective cylinder, the connecting device body cylinder is provided with a gas outlet hole and an oil production hole, and a check valve allowing formation fluid to flow from outside to inside is arranged at the oil production hole; during the gas injection process, the oil production hole is closed under the action of the check valve, and the gas flows through the electrically controlled pressure balance gas nozzle from the gas outlet hole; during the oil production process, the electrically controlled pressure balance gas nozzle is closed, the oil production hole is opened, and the formation fluid enters the lower section of the oil pipe through the connecting device body cylinder.

[0011] In a preferred embodiment of the present application, the control center unit is a high-temperature chip, the control center unit can store the pressure data collected by the pressure test component and the flow data collected by the gas flow meter, and can encode and decode to encode the pressure data and the flow data into executable electric control instructions, and the electric control instructions are transmitted to control the small-diameter motor to adjust the opening degree of the electrically controlled pressure balance gas nozzle.

[0012] In a preferred embodiment of the present application, the pressure test component adopts a piezoresistive sensor.

[0013] In a preferred embodiment of the present application, the small-diameter motor is connected with the electrically controlled pressure balance gas nozzle through a transmission assembly, the transmission assembly converts high-speed rotation into low-speed and large-torque rotation to drive the electrically controlled pressure balance gas nozzle to adjust the opening degree.

[0014] In a preferred embodiment of the present application, the gas flow meter comprises a multi-stage orifice plate.

[0015] In a preferred embodiment of the present application, the first sheath and the second sheath are arranged in the outer protective cylinder, the high-temperature battery and the control center unit are arranged in the first sheath, and the small-diameter motor is arranged in the second sheath; one end of the first sheath away from the injection-production connecting device is sealingly connected with a tail cap, and a centralizing sleeve is arranged on the outer wall of the tail cap.

[0016] In a preferred embodiment of the present application, the two ends of the outer casing are connected to the lower section of the oil pipe through a first connecting part and a second connecting part respectively.

[0017] In a preferred embodiment of the present application, the second packer comprises a body central pipe, a seat sealing rubber sleeve and a protection rubber sleeve are arranged on the outer wall of the body central pipe, a releasing structure is arranged at the end of the seat sealing rubber sleeve away from the protection rubber sleeve, and a seat sealing structure is arranged at the end of the protection rubber sleeve away from the seat sealing rubber sleeve.

[0018] In a preferred embodiment of the present application, a third connecting part is arranged at one end of the body central pipe, the third connecting part is connected to a safety joint and a centralizer, the safety joint can be sheared under the action of tension; a fourth connecting part is arranged at the other end of the body central pipe, and the fourth connecting part is connected to the lower section of the oil pipe.

[0019] In a preferred embodiment of the present application, the inner wall and the outer wall of the lower section of the oil pipe are provided with a corrosion-resistant coating.

[0020] The object of the present application can also be achieved by a horizontal well intelligent segmented production method, comprising the following steps:

[0021] Step a, horizontal well treatment, the horizontal well intelligent segmented production process string as claimed in any one of claims 1 to 12 is lowered into the well to a set position and is set, and a high-pressure injection and production wellhead is installed;

[0022] Step b, test injection: the downhole intelligent injection and production device automatically opens the electrically controlled pressure balanced gas nozzle according to the preset opening time, and the ground opens the gas injection flow test; after the pressure is stable, the constant flow gas injection mode is opened according to the full well injection allocation;

[0023] Step c, segmented automatic adjustment constant flow gas injection: the downhole intelligent injection and production device automatically adjusts the electrically controlled pressure balanced gas nozzle according to the preset segmented injection amount, realizes the automatic adjustment of the segmented gas amount, and real-time monitors the segmented pressure and flow data and stores them in the control center unit during the injection process;

[0024] Step d, during the injection process, if the segmented injection amount needs to be adjusted or the segmented pressure data needs to be grasped, the wellbore pressure and flow ordered codes are sent to the central measurement and control assembly through the ground control device, the downhole intelligent injection and production device detects the ordered codes, decodes and executes the related operations; when the instruction needs to be returned, the downhole intelligent injection and production device returns the segmented dynamic data to the ground control device by opening and closing the electrically controlled pressure balanced gas nozzle, the ground control device detects and completes the decoding, and displays the specific values;

[0025] Step e, soak: when the designed injection amount is reached, the ground control device sends an instruction to the central measurement and control assembly to close each electrically controlled pressure balanced gas nozzle; the well is soaked according to the set time.

[0026] Step f, oil production: after the soak well is completed, the ground begins to test production, and the ground oil nozzle opening is controlled during the test production process; the gas overflow is recovered in time in the initial stage of oil production;

[0027] Step g, carry out the next round of energy supplement: when the single well production is reduced to the production before the test, stop oil production; after stopping pumping, seal the wellhead, convert to injection process, and carry out the second round of energy supplement mining according to steps b to f.

[0028] In a preferred embodiment of the present application, in step b, the bottom hole fracture pressure of the fractured layer is calculated according to the fracturing construction parameters, the highest bottom hole injection pressure is obtained by converting 90% of the fracture pressure, and the wellhead injection pressure is determined.

[0029] In a preferred embodiment of the present application, in step c, the bottom hole underground void volume of the gas injection well is calculated according to the fracturing reconstruction and production data, and the gas injection amount required by the gas injection well is obtained when the throughput supplements the formation void; according to the segmented liquid production flow and segmented pressure of different layers, the segmented gas injection amount is subdivided and set in the control center unit of the downhole intelligent injection and production device, so as to automatically control the segmented flow in the later injection process.

[0030] In a preferred embodiment of the present application, step a includes the following steps:

[0031] Step a1: sand washing and well flushing treatment are performed on the horizontal well to be implemented;

[0032] Step a2: horizontal well segment pressure measurement: according to the test results, the interlayer channeling condition and the segmented injection pressure are judged, and then the second packer seat sealing position for segmented huff and puff is guided;

[0033] Step a3, the intelligent huff and puff pipe string part is lowered into the horizontal well, the ground is pressed, and the first packer and the second packer are sealed;

[0034] Step a4, lower the upper segment injection and production pipe string part: after the intelligent huff and puff pipe string part is sealed, the first packer is released, the oil pump is lowered into the design depth of the production string together with the upper segment tubing, the plunger is lowered into the well together with the sucker rod, and the high-pressure injection and production wellhead is installed.

[0035] As described above, the horizontal well intelligent segmented huff and puff process pipe string and mining method provided by the present application has the following advantages

[0036] Beneficial effects:

[0037] The intelligent segmented throughput process string for horizontal wells provided by the present invention meets the needs of segmented injection, segmented production, constant flow control, real-time monitoring of pressure and flow, and remote regulation of segmented injection volume for different strings. The use of the present invention can achieve balanced and effective energy replenishment of tight reservoirs such as shale oil, improve the maximum reserve utilization of the entire well section of the horizontal well, and effectively improve the recovery rate; the present invention forms a same-well injection and production string, realizes the replacement of the string without pressure, and reduces the risk of high-pressure operations on site; the present invention adopts the downhole real-time monitoring function to realize the refined control of segmented energy replenishment and dynamic continuous monitoring, improves the process effect, achieves differentiated design of segmented gas injection volume, real-time monitoring and control of segmented gas injection volume and pressure, and achieves remote adjustment of segmented gas injection volume and segmented oil production without moving the string; the present invention can realize downhole segmented flow testing and adjustment, remote long-term monitoring, and the string meets the process requirements of carbon dioxide corrosion resistance and segmented throughput without moving the string. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] The following drawings are only intended to illustrate and explain the present invention, and are not intended to limit the scope of the present invention.

[0039] in:

[0040] Figure 1 : It is a schematic diagram of the horizontal well intelligent segmented throughput process string of the present invention.

[0041] Figure 2 : This is a schematic diagram of the appearance of the downhole intelligent injector of the present invention.

[0042] Figure 3 : is a cross-sectional view of the downhole intelligent injector of the present invention.

[0043] Figure 4 : is a schematic diagram of the second packer of the present invention.

[0044] In the picture:

[0045] 1. Upper section tubing; 2. Sucker rod; 3. Well pump; 4. Casing; 5. First packer; 6. Lower section tubing; 7. Downhole intelligent injector / recovery device; 8. Second packer; 9. Screen tube nipple; 10. Connecting tube body; 11. Check valve; 12. First casing; 13. Second casing; 14. Center pipe; 15. Tail cap; 16. Centralizing sleeve; 17. Central measurement and control assembly; 18. First connection; 19. Outer casing; 20. Injection / recovery Connector; 21. Air outlet; 22. Oil production hole; 23. Second connection part; 24. High-temperature battery; 25. Control center unit; 26. Pressure test assembly; 27. Small-diameter motor; 28. Transmission assembly; 29. ​​Electronically controlled pressure balancing air nozzle; 30. Air flow meter; 31. Air inlet channel; 32. Third connection part; 33. Unsealing structure; 34. Sealing rubber cylinder; 35. Protective rubber cylinder; 36. Sealing structure; 37. Fourth connection part. DETAILED DESCRIPTION

[0046] In order to make the technical features, objectives and effects of the present application more clearly understood, the specific embodiments of the present application will be described with reference to the accompanying drawings.

[0047] The specific embodiments of the present application described herein are for the purpose of explanation and are not to be construed as limiting the present application in any manner. Those skilled in the art will conceive any possible variations based on the present application under the teachings of the present application, which should be considered as falling within the scope of the present application. It should be noted that when an element is referred to as being "provided on" another element, it can be directly on the other element or there can be a mediating element. When an element is referred to as being "connected" to another element, it can be directly connected to the other element or there can be a mediating element. The terms "mounting", "connection", and "connection" should be broadly interpreted, for example, they can be mechanical connection or electrical connection, or internal communication between two elements, or direct connection or indirect connection through a medium. Those skilled in the art can understand the specific meanings of the above terms according to the specific circumstances. The terms "vertical", "horizontal", "up", "down", "left", "right", and similar expressions used herein are for the purpose of illustration only and do not indicate the only embodiment.

[0048] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which the present application belongs. The terms used in the specification of the present application are only for the purpose of describing the specific embodiments and are not intended to limit the present application. The term "and / or" used herein includes any and all combinations of one or more related listed items.

[0049] As shown in Figures 1 to 4 The present application provides a horizontal well intelligent segmented throughput process string, which is directly lowered into the well or the casing 4 when in use, and the wellhead of the horizontal well is implemented with a high-pressure gas injection wellhead to realize injection and production process at the wellhead.

[0050] As shown in Figure 1 The horizontal well intelligent segmented throughput process string of the present application comprises,

[0051] The upper section injection and production string part comprises an upper section tubing 1, a sucker rod 2, and a sucker rod pump 3 (tubular pump). In a specific embodiment of the present application, the upper section tubing 1, the sucker rod 2, and the sucker rod pump 3 are designed with a gas-tight buckle, and the sucker rod pump 3 (tubular pump) is designed with a gas-proof device to ensure the reliability of the string.

[0052] The intelligent through tubing string part comprises a lower section of tubing 6, the first packer 5 is arranged at one end of the lower section of tubing 6 adjacent to the upper section of injection and production tubing string part; a plurality of downhole intelligent injection and production devices 7 are arranged at intervals in the horizontal section of the lower section of tubing 6, and the second packer 8 is arranged between two adjacent downhole intelligent injection and production devices 7 to segmentally seal the horizontal well; the tail end of the lower section of tubing 6 is connected with the screen pipe nipple 9, and the screen pipe nipple 9 is a screen pipe bottom valve integrated nipple; the arrangement of the plurality of downhole intelligent injection and production devices 7 and the second packer 8 meets the requirements of segmented and layered gas injection and oil production.

[0053] In a specific embodiment of the present application, the intelligent through tubing string part is arranged above 50 meters and below the build-up point; the first packer 5 is a Y445 drillable packer, the second packer 8 is a Y341 drillable packer, the lower section of tubing 6, the second packer 8 (Y341 drillable packer), the downhole intelligent injection and production device and the screen pipe bottom valve integrated nipple are all designed with gas-tight sub, and the lower section of tubing 6 is designed with N80 tubing and anticorrosive coating inside and outside.

[0054] The downhole intelligent injection and production device 7 comprises an outer sleeve 19 and an injection and production communication device 20, and a center control component 17 is arranged in the outer sleeve 19 and the injection and production communication device 20, and the center control component 17 is used for layered injection and production monitoring and control.

[0055] The horizontal well intelligent segmented through tubing string provided by the present application meets the requirements of segmented injection, segmented production, constant flow control, real-time pressure and flow monitoring, remote control of segmented injection amount, and can realize balanced and effective energy supplement of shale oil and other dense reservoirs, improve the maximum degree of reservoir production of the whole section of the horizontal well, and effectively improve the recovery rate; the present application forms a same-well injection and production tubing string, realizes non-pressure replacement of the tubing string, and reduces the risk of high-pressure operation on site; the present application adopts downhole real-time monitoring function, realizes fine control and dynamic continuous monitoring of segmented energy supplement, improves the process effect, realizes differentiated design of segmented gas injection amount, real-time monitoring and control of segmented gas injection amount and pressure, and realizes remote adjustment of segmented gas injection amount and segmented oil production without moving the tubing string; the present application can realize downhole segmented flow testing and adjustment, remote long-term monitoring, and the tubing string meets the process requirements of corrosion-resistant carbon dioxide and non-tubing string segmented through.

[0056] Further, the center control component 17 is designed with mechatronics, and realizes layered monitoring and control function;

[0057] As Figure 2 , Figure 3As shown, the center control component 17 includes a high-temperature battery 24, a control center unit 25, a pressure test component 26, an electrically controlled pressure balance gas nozzle 29, a small-diameter motor 27 and a gas flow meter 30. The high-temperature battery 24 is electrically connected with the control center unit 25. The pressure test component 26, the small-diameter motor 27 and the gas flow meter 30 are electrically connected with the control center unit 25. The control center unit 25 controls the small-diameter motor 27 to adjust the opening degree of the electrically controlled pressure balance gas nozzle 29 according to the pressure data collected by the pressure test component 26 and the flow data collected by the gas flow meter 30. The small-diameter motor 27 adjusts the opening degree of the electrically controlled pressure balance gas nozzle 29 to control the downhole flow rate in a constant current manner.

[0058] Further, as shown in Figure 2 、 Figure 3 the injection-production communication device 20 includes a communication device body cylinder 10 in communication with the outer casing 19. The communication device body cylinder 10 is provided with a gas outlet hole 21 and an oil production hole 22. The oil production hole 22 is provided with a check valve 11 allowing the formation fluid to flow from outside to inside. During the gas injection process, the oil production hole 22 is closed under the action of the check valve 11. The gas entering the gas inlet channel 31 flows through the electrically controlled pressure balance gas nozzle 29 from the gas outlet hole 21. During the oil production process, the electrically controlled pressure balance gas nozzle 29 is closed, and the oil production hole 22 is opened. The formation fluid enters the lower section of the oil pipe 6 through the communication device body cylinder 10.

[0059] Further, the high-temperature battery 24 is a high-temperature lithium battery, which meets the 120℃ downhole application. The control center unit 25 is a high-temperature chip. The control center unit 25 can store the pressure data collected by the pressure test component 26 and the flow data collected by the gas flow meter 30, and can encode and decode to encode the pressure data and the flow data into executable electric control instructions. The electric control instructions are transmitted to the control small-diameter motor 27 to adjust the opening degree of the electrically controlled pressure balance gas nozzle 29.

[0060] The control center unit 25 is designed with a gated clock technology. The sleep state is between the collection points. N same modules work at the same time. The clock frequency can be reduced to 1 / N of the original frequency. The total output in the circuit maintains the original speed, shortens the processing time and reduces the power consumption.

[0061] Further, the pressure test component 26 adopts a piezoresistive sensor. Three pressure points are designed to monitor the pressure after the nozzle, the pressure before the flow meter and the pressure after the flow meter. The pressure value before the flow meter is used to receive the flow and pressure wave code instructions sent from the ground, and the pressure signal is converted into an electric signal and sent to the control center unit.

[0062] The tested pressure before the flow meter and the pressure after the flow meter can obtain the segmented gas injection amount and send it to the control center unit. The control center unit compares with the target flow rate to automatically adjust the opening degree of the electrically controlled pressure balance gas nozzle 29, realizing the constant current control of the downhole flow rate.

[0063] Further, as shown in Figure 3 The small-diameter motor 27 is connected to the electrically-controlled pressure balance gas nozzle 29 through a transmission assembly 28, which converts high-speed rotation into low-speed and large-torque rotation to drive the electrically-controlled pressure balance gas nozzle 29 to adjust the opening degree. The electrically-controlled pressure balance gas nozzle 29 is designed with balanced pressure and can be adjusted with small torque under high pressure difference.

[0064] In an embodiment, the diameter of the small-diameter motor 27 is 23 mm, which is convenient for downhole integration design, and the maximum torque reaches 28 N.m.

[0065] Further, the gas flow meter 30 includes multiple-stage orifice plates, and the orifice plate diameter is increased. In an embodiment, five-stage orifice plates are used to establish a large pressure drop, thereby improving the flow test accuracy.

[0066] The downhole intelligent injection-production device 7 is designed with downhole automatic measurement and adjustment process, that is, before being lowered into the well, the control center unit of the downhole intelligent injection-production device 7 has set the injection allocation of a single section as input; after being lowered into the well, the opening time is controlled by setting time, and after being opened, the target flow is automatically adjusted; at the same time, the electrically-controlled pressure balance gas nozzle 29 can be remotely controlled to be opened, and the communication mode with the ground adopts fluid wave code form, the ground establishes flow fluctuation by changing the flow in the wellbore, the downhole intelligent injection-production device 7 detects the flow change, simultaneously analyzes the instruction meaning, and performs corresponding actions, and in the process of detecting the flow fluctuation, the pressure test assembly 26 synchronously tests the pressure change in the wellbore, analyzes the pressure fluctuation instruction, checks the flow instruction code, and improves the test accuracy.

[0067] Further, as shown in Figure 3 The first sheath 12 and the second sheath 13 are arranged in the outer protector 19, the high-temperature battery 24 and the control center unit 25 are arranged in the first sheath 12, and the small-diameter motor 27 is arranged in the second sheath 13; the tail cap 15 is sealingly connected to the end of the first sheath 12 away from the injection-production communication device 20, and the outer wall of the tail cap 15 is sleeved with the centralizing sleeve 16.

[0068] Further, as shown in Figure 2 The two ends of the outer protector 19 are connected to the lower section of the tubing 6 through the first connecting part 18 and the second connecting part 23, respectively.

[0069] The outer protector 19 and the communication device body 10 are designed with 13Cr material, the tail cap 15 is designed with 13Cr material and is used to seal the high-temperature battery 24 and the electrically-controlled assembly. The centralizing sleeve 16 is made of high-elasticity alloy steel and plays a centralizing role. The first connecting part 18 and the outer protector 19, the outer protector 19 and the communication device body 10, the communication device body 10 and the second connecting part 23, and the tail cap 15 and the first sheath 12 are connected through threads, and the two structures connected are sealed by sealing rings, the sealing rings are designed with modified fluororubber and meet the requirements of 60 MPa and 120°C long-term use downhole.

[0070] Further, as shown in Figure 4 the second packer 8 includes a body central tube 14, a seat sealing rubber tube 34 and a protection rubber tube 35 are arranged on the outer wall of the body central tube 14, the seat sealing rubber tube 34 is arranged with an unsealing structure 33 away from the end of the protection rubber tube 35, and the protection rubber tube 35 is arranged with a seat sealing structure 36 away from the end of the seat sealing rubber tube 34.

[0071] Further, as shown in Figure 4 one end of the body central tube 14 is provided with a third connecting part 32, the third connecting part 32 connects a safety joint and a centralizer, the safety joint can be sheared under the action of tension, and the safety joint connects the lower section of the oil pipe 6; the other end of the body central tube 14 is provided with a fourth connecting part 37, and the fourth connecting part 37 connects the lower section of the oil pipe 6.

[0072] The safety joint adopts a tension shearing design, when the packer below the pipe string cannot be normally pulled out, the pipe string will be sheared at the safety joint under the action of tension. The unsealing structure adopts a non-metallic drillable material design, which can realize that after the unsealing structure is ground and drilled, the rubber tube loses support, is recovered inward, and the packer is unsealed. The second packer 8 (Y341 drillable packer) adopts a protection rubber tube design, when the packer is sealed, the pressure at the lower end of the packer is usually higher than the pressure at the upper part, in order to avoid that the packer is unsealed in advance, the protection rubber tube will be continuously compressed upward under the action of pressure difference, the rubber tube of the packer is kept in a compressed state, and the effective period of the pipe string is prolonged.

[0073] Further, the inner wall and the outer wall of the lower section of the oil pipe 6 are provided with a corrosion-resistant coating.

[0074] The application also provides a horizontal well intelligent segmented throughput mining method, which comprises the following steps:

[0075] Step a, horizontal well treatment, the horizontal well intelligent segmented throughput process string is lowered into the well to a set position and is set, and a high-pressure injection and production wellhead is installed;

[0076] Specifically, the following steps are included:

[0077] Step a1: the sand washing and well flushing treatment of the horizontal well to be implemented are completed; and the engineering logging structure within nearly one year is provided, so that the wellbore has the requirement of carbon dioxide injection;

[0078] Step a2: horizontal well segmented pressure measurement: a double-sealing single-clamping pipe string (prior art) is used to lower into the horizontal section of the horizontal well, and pressure test is carried out in sections, the interlayer channeling condition and segmented injection pressure are judged according to the test results, and then the seat sealing position of the second packer 8 for segmented throughput is guided;

[0079] Step a3, the intelligent throughput pipe string part is lowered into the horizontal well, the ground is pressed, and the first packer and the second packer are sealed;

[0080] Specifically, the segmented intelligent throughput pipe string part is lowered according to the segmented design. Taking four segments as an example, the Y445 drillable packer, the tubing, the downhole intelligent injection and production device one, the Y341 drillable packer one, the downhole intelligent injection and production device two, the Y341 drillable packer two, the downhole intelligent injection and production device three, the Y341 drillable packer three, the downhole intelligent injection and production device four, the Y341 drillable packer four, and the screen pipe bottom valve integrated nipple are sequentially lowered according to the design, and after being lowered to a position, the ground is pressurized, and each packer in the well is set.

[0081] Step a4, lowering the upper segment injection and production pipe string part: after the intelligent throughput pipe string part is set, the first packer 5 is unclamped, the sucker rod 2 is lowered into the well together with the plunger together with the oil pump 3, and the upper segment tubing 1 is lowered into the oil production pipe string design depth, and the high-pressure injection and production wellhead is installed.

[0082] Step b, test injection: the downhole intelligent injection and production device automatically opens the electrically controlled pressure balanced gas nozzle 29 according to the preset opening time, the ground opens the gas injection flow test injection, and after the pressure is basically stable, the constant flow gas injection mode is opened according to the full well injection allocation.

[0083] Specifically, according to the fracturing construction parameters, the well bottom fracture pressure of the fracturing layer is calculated, the highest well bottom injection pressure is obtained by converting 90% of the fracture pressure to prevent the formation fracture from opening, and then the wellhead injection pressure is determined.

[0084] The calculation formula is as follows:

[0085] P 注气井口max =P 破裂 *0.9-P CO2液柱 +P 摩阻

[0086] Wherein, P 注气井口max is the maximum wellhead injection pressure, P 破裂 is the well bottom fracture pressure, P CO2液柱 is the carbon dioxide miscible pressure, and P 摩阻 is the flow resistance between the CO2 flow and the pipe string sidewall.

[0087] The carbon dioxide miscible pressure P CO2液柱 of the reservoir needs to be tested first. First, the porosity and pore volume are tested and determined; the water permeability is tested; the oil drives the water to form the bound water; then the test back pressure is set, the CO2 is displaced to the residual oil state at a constant flow rate, the cumulative oil production at different times and the pressure difference between the two ends of the capillary core are recorded, and the gas drive recovery rate is calculated; when the oil is driven to more than 1.2 PV, the back pressure is changed, and the above process is repeated; according to the test results, the minimum pressure corresponding to the gas drive recovery rate of 90% to 95% is the minimum miscible pressure.

[0088] Step c, subsection automatic adjusting constant flow injection: the downhole intelligent injection and production device automatically adjusts the electric control pressure balance gas nozzle 29 according to the preset subsection injection amount, realizes automatic adjustment of the subsection gas amount, the adjustment period can be set by itself according to the need, and the subsection pressure and flow data are monitored in real time during the whole injection process and stored in the control center unit 25.

[0089] Specifically, according to the fracturing reconstruction and production data, the bottom hole underground depletion volume of the gas injection well is calculated, when the throughput supplements the formation depletion, the gas injection amount of the gas injection well is obtained; according to the subsection liquid production flow and the subsection pressure of different layers, the subsection injection amount is further subdivided, and the subsection injection amount is set in the control center unit of the downhole intelligent injection and production device, so as to automatically control the subsection flow in the later injection process.

[0090] Underground depletion volume = cumulative injected underground volume of water / gas - (cumulative produced underground volume of oil + cumulative produced underground volume of water + cumulative produced underground volume of gas).

[0091] Step d, during the injection process, if the subsection injection amount needs to be adjusted or the subsection pressure data needs to be grasped, the ground control device sends a control instruction to the center measurement and control assembly, the ground opening degree adjustment establishes the ordered code of the wellbore pressure and flow, the downhole intelligent injection and production device detects the ordered code, decodes and executes the related operation; when the instruction needs to be returned, the downhole intelligent injection and production device returns the subsection dynamic data to the ground control device by using the switch electric control pressure balance gas nozzle, the ground control device detects and completes the decoding, and displays the specific value;

[0092] Step e, soak: when the whole well and the subsection reach the designed injection amount, the ground control device sends an instruction to the center measurement and control assembly to close each electric control pressure balance gas nozzle (the ground coding closes all the electric control pressure balance gas nozzles of the downhole intelligent injection and production device); after closing, the soak is carried out according to the set time; the wellbore pressure change needs to be monitored in real time during the soak process, and the soak time is optimized in time according to the pressure change.

[0093] Specifically, the soak time adopts the experience method of similar reservoirs, and is fully combined with the soak infiltration speed of similar reservoirs in the early stage, and the wellbore pressure change is monitored at the same time, when the pressure drop amplitude is below 0.01 MPa / day (different blocks need to be optimized appropriately), the subsection oil production needs to be started.

[0094] Step f, oil production: after the soak is completed, the ground starts to produce, and the opening degree of the ground oil nozzle (existing technology) is controlled during the production process to avoid pressure out of control; there will be carbon dioxide overflow in the early stage of oil production, and the overflow gas needs to be recovered in time;

[0095] During the blowout process, the blowout speed needs to be strictly controlled, and carbon dioxide will overflow in the early stage of blowout, and the recovery needs to be done well.

[0096] Step g, carry out the next round of energy supplement: when the single well production is reduced to the production before the test, stop oil production; after stopping pumping, seal the well head, convert to injection process, and carry out the second round of energy supplement mining according to steps b to f.

[0097] The horizontal well intelligent segmented production method of the present application realizes effective energy supplement of shale oil and other dense reservoirs, and achieves differentiated design of segmented gas injection volume, real-time monitoring and control of segmented gas injection volume and pressure, and remote adjustment of segmented gas injection volume and segmented oil production without moving the pipe column; the present application can realize downhole segmented flow testing and adjustment, remote long-term monitoring, and the pipe column meets the process requirements of carbon dioxide corrosion resistance and segmented production without moving the pipe column.

[0098] As described above, the horizontal well intelligent segmented production method of the present application has the following advantages

[0099] Beneficial effects:

[0100] The horizontal well intelligent segmented production method of the present application realizes effective energy supplement of shale oil and other dense reservoirs, and achieves differentiated design of segmented gas injection volume, real-time monitoring and control of segmented gas injection volume and pressure, and remote adjustment of segmented gas injection volume and segmented oil production without moving the pipe column; the present application can realize downhole segmented flow testing and adjustment, remote long-term monitoring, and the pipe column meets the process requirements of carbon dioxide corrosion resistance and segmented production without moving the pipe column.

[0101] The above description is only a specific embodiment of the present application, and is not intended to limit the scope of the present application. Any equivalent changes and modifications made by those skilled in the art without departing from the concept and principles of the present application shall fall within the scope of the present application.

Claims

1. A horizontal well intelligent segmented throughput process string, characterized by: include, The upper injection and production string includes the upper oil pipe, sucker rod and oil pump; The intelligent throughput string comprises a lower section of tubing, wherein a first packer is connected to one end of the lower section of tubing adjacent to the upper section of the injection and production string; a plurality of downhole intelligent injectors are spaced apart in the horizontal section of the lower section of tubing, and a second packer is provided between two adjacent downhole intelligent injectors to isolate and segment the horizontal well; the tail end of the lower section of tubing is connected to a screen tube nipple; the downhole intelligent injector comprises an outer casing and an injection and production connector, wherein a central measurement and control component is provided in the outer casing and the injection and production connector, and the central measurement and control component is used for monitoring and controlling stratified injection and production; The central measurement and control assembly includes a high-temperature battery, a control center unit, a pressure testing assembly, an electrically controlled pressure balancing gas nozzle, a small-diameter motor, and a gas flow meter. The high-temperature battery is electrically connected to the control center unit. The pressure testing assembly, the small-diameter motor, and the gas flow meter are all electrically connected to the control center unit. The control center unit controls the small-diameter motor to adjust the opening of the electrically controlled pressure balancing gas nozzle based on the pressure data collected by the pressure testing assembly and the flow data collected by the gas flow meter. The small-diameter motor adjusts the opening of the electrically controlled pressure balancing gas nozzle to control the downhole flow at a constant flow rate. The injection-production interconnector comprises a connecting tube body connected to the outer casing, the connecting tube body is provided with an air outlet and an oil production hole, and the oil production hole is provided with a check valve allowing formation fluid to flow from outside to inside; During the gas injection process, the oil production hole is closed by the check valve, and the gas flows from the gas outlet through the electronically controlled pressure balancing nozzle; During the oil production process, the electrically controlled pressure balancing valve is closed, the oil production hole is opened, and the formation fluid enters the lower section of the oil pipe through the communicating vessel body.

2. The horizontal well intelligent segmented throughput process string according to claim 1, characterized in that: The control center unit is a high-temperature chip. The control center unit can store the pressure data collected by the pressure testing component and the flow data collected by the gas flow meter, and can encode and decode to convert the pressure data and flow data into executable electronic control instructions. The electronic control instructions are transmitted to control the small-diameter motor to adjust the opening of the electronically controlled pressure balancing gas nozzle.

3. The horizontal well intelligent segmented throughput process string according to claim 1, characterized in that: The pressure testing assembly adopts a piezoresistive sensor.

4. The horizontal well intelligent segmented throughput process string according to claim 1, characterized in that: The small-diameter motor is connected to the electronically controlled pressure-balancing air nozzle via a transmission assembly, and the transmission assembly converts high-speed rotation into low-speed, high-torque rotation to drive the electronically controlled pressure-balancing air nozzle to adjust its opening.

5. The horizontal well intelligent segmented throughput process string according to claim 1, characterized in that: The gas flow meter includes a multi-stage orifice plate.

6. The horizontal well intelligent segmented throughput process string according to claim 1, characterized in that: A first sheath and a second sheath are inserted into the outer casing, the high-temperature battery and the control center unit are arranged in the first sheath, and the small-diameter motor is arranged in the second sheath; the first sheath is sealed and connected to a tail cap at one end away from the injection-production connector, and a straightening sleeve is sleeved on the outer wall of the tail cap.

7. The horizontal well intelligent segmented throughput process string according to claim 1, characterized in that: Both ends of the outer casing are connected to the lower section oil pipe via a first connecting portion and a second connecting portion respectively.

8. The horizontal well intelligent segmented throughput process string according to claim 1, characterized in that: The second packer includes a main body center tube, on the outer wall of which a sealing rubber tube and a protective rubber tube are provided. An unsealing structure is provided at one end of the sealing rubber tube away from the protective rubber tube, and a sealing structure is provided at one end of the protective rubber tube away from the sealing rubber tube.

9. The horizontal well intelligent segmented throughput process string according to claim 8, characterized in that: A third connection portion is provided at one end of the central tube of the main body, the third connection portion is connected to the safety joint and the centralizer, and the safety joint can be sheared under the action of tension; a fourth connection portion is provided at the other end of the central tube of the main body, the fourth connection portion is connected to the lower section of the oil pipe.

10. The horizontal well intelligent segmented throughput process string according to claim 1, characterized in that: The inner wall and outer wall of the lower section oil pipe are both provided with anti-corrosion coatings.

11. A horizontal well intelligent segmented throughput mining method, characterized in that: The following steps are involved: Step a, horizontal well treatment, running the horizontal well intelligent segmented throughput process string according to any one of claims 1 to 10 into the well to set a position and set it, and installing a high-pressure injection and production wellhead; Step b, test injection: the downhole intelligent injector automatically opens the electronically controlled pressure balancing gas nozzle according to the preset opening time, and the surface gas injection process is started for test injection; after the pressure stabilizes, the constant flow gas injection mode is started according to the full well injection volume; Step c, automatic adjustment of constant flow gas injection in sections: the downhole intelligent injector automatically adjusts the electronically controlled pressure balancing gas nozzle according to the preset section gas injection volume to achieve automatic adjustment of the section gas volume. During the injection process, the section pressure and flow data are monitored in real time and stored in the control center unit; Step d: During the injection process, if it is necessary to adjust the segmented gas injection volume or to obtain segmented pressure data, the ground control device sends the wellbore pressure and flow sequence codes to the central measurement and control component. The downhole intelligent injector detects the sequence codes, decodes them, and executes relevant operations. When it is necessary to send back instructions, the downhole intelligent injector uses the switch electronically controlled pressure balancing nozzle to send segmented dynamic data back to the ground control device. The ground control device detects and completes the decoding and displays the specific values. Step e, soaking the well: When the designed injection volume is reached, the ground control device sends a command to the central measurement and control component to close each electronically controlled pressure balancing valve; soak the well according to the set time; Step f, oil production: After the well is soaked, test production begins on the ground. During the test production, the opening of the surface oil nozzle is controlled; the gas overflowed is recovered in time at the initial stage of oil production; Step g, carry out the next round of energy replenishment: when the single well production drops to the production before the test, stop oil production; after stopping pumping, seal the wellhead and switch to the injection process, and carry out the second round of energy replenishment production according to steps b to f.

12. The horizontal well intelligent segmented throughput mining method according to claim 11, characterized in that: In step b, the bottom hole burst pressure of the fractured layer is calculated according to the fracturing operation parameters, and the maximum bottom hole injection pressure is converted according to 90% of the burst pressure to determine the wellhead injection pressure.

13. The horizontal well intelligent segmented throughput mining method according to claim 11, characterized in that: In step c, the underground deficit volume at the bottom of the gas injection well is calculated based on the fracturing transformation and production data. When the throughput supplements the formation deficit, the required gas injection volume of the gas injection well is obtained; based on the segmented liquid production flow rate and segmented pressure of different layers, the segmented gas injection volume is subdivided and set in the control center unit of the downhole intelligent injector to automatically control the segmented flow rate during the later injection process.

14. The horizontal well intelligent segmented throughput mining method according to claim 11, characterized in that: Step a includes the following steps: Step a1: Complete sand flushing and well cleaning for the entire horizontal well; Step a2: Horizontal well segmented pressure testing: Determine the inter-segment channeling and segmented injection pressure based on the test results, and then guide the seating position of the second packer used for segmented throughput; Step a3: running the intelligent throughput string into the horizontal well, applying pressure on the surface, and seating the first and second packers; Step a4, lowering the upper injection and production string: After the intelligent throughput string is seated, the first packer is released, and the wellbore pump together with the upper section of the oil pipe is lowered to the designed depth of the production string. The plunger together with the sucker rod is lowered into the well, and the high-pressure injection and production wellhead is installed.

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