A layered production string

Abstract

This invention relates to a stratified oil production process tubing string, belonging to the technical field of oilfield production tools. The solution includes a drop string, comprising packers and a switch connecting the two packers to the drop string. The switch includes a lower tube body with an axially formed oil pumping channel. A through-hole connecting the oil pumping channel and the oil layer is formed on the side wall of the lower tube body. An inner tube body is rotatably fitted onto the inner circumference of the oil pumping channel. The inner tube body has a radially formed inner tube channel for connecting the oil pumping channel. The inner tube body also has a channel connecting the through-hole and the oil pumping channel. The inner tube body has a first position in the circumferential direction where the channel connects to the through-hole and a second position where the channel is offset from and closes the through-hole. A slot is provided on the inner side of the inner tube body for rotating the inner tube body circumferentially via a protruding structure. This solution addresses the problem in existing technologies where, in cases of severe casing leakage where pressurization is impossible or the battery is depleted, the switch body's switching action cannot be controlled, thus affecting normal field production.

Description

Technical Field

[0001] This invention relates to a stratified oil production process tubing, belonging to the technical field of oilfield production tools. Background Technology

[0002] In the later stages of oil well production, due to the decrease in oil content, water injection is required for oil displacement. This increases the water content of the oil layer. To improve production and achieve water control and oil stabilization, water-finding and plugging devices are used to locate and plug water in each oil layer. Mechanical water-finding and plugging technology is a commonly used water-plugging technique in oilfield development and production. It typically involves lowering a multi-stage stationary tubing string into the well, placing slip packers and water-finding and plugging switches inside the string. The water content of each layer is determined based on the fluid produced during normal production to identify high-water-cut layers. Hydraulic injection in the annulus closes the corresponding water-finding and plugging switches, achieving the goal of water-finding and plugging without moving the tubing string.

[0003] Chinese utility model patent publication number CN202866752U discloses a push-type downhole water-plugging switch. In use, this utility model, together with a packer, plug, and release mechanism, forms a water-plugging string. After the packer is set, the release mechanism is activated. The downhole water-plugging switch operates by detecting and plugging water via surface pressure pulse signals. The switch is controlled by the number of pressurization cycles within a certain time period, with pressure values ​​ranging from 5MPa to 10MPa. A microcontroller receives the pressure pulse signals; if the microcontroller counter receives 5 pulse signals within 10 minutes, it drives the push-type water-plugging switch to open; if it receives 8 signals within 10 minutes, it drives the switch to close.

[0004] Although the aforementioned downhole switch can achieve intelligent control of stratified oil production, it requires, on the one hand, that there be no casing leakage above the top packer and that the pressure be stabilized during pressurization; on the other hand, it requires power from a downhole battery to ensure that the signal can be accurately transmitted to the control circuit to control the switching action of the water-finding switch. In field use, when wells with severe casing leakage cannot be pressurized or the battery is depleted, the switching action of the water-finding switch cannot be controlled, affecting normal field production. Summary of the Invention

[0005] The purpose of this invention is to provide a stratified oil production process tubing to solve the problem in the prior art where the switching action of the water-finding and plugging switch cannot be controlled when the well is severely leaking and cannot be pressurized or the battery is depleted, thus affecting normal on-site production.

[0006] To achieve the above objectives, the present invention includes:

[0007] A stratified oil recovery process tubing string includes a dropout tubing string. The dropout tubing string includes packers for sealing positions above and below corresponding oil layers within the casing, and a switch connecting the two packers through a central hole in one of the packers to the dropout tubing string. The switch includes a lower tube body with an axially formed oil pumping channel. A through hole connecting the oil pumping channel and the oil layer is formed on the side wall of the lower tube body. An inner tube body is rotatably fitted on the inner circumferential surface of the oil pumping channel. The inner tube body has an inner tube channel for connecting the oil pumping channel radially. The inner tube body also has a channel for connecting the through hole and the oil pumping channel. The inner tube body has a first position in the circumferential direction of the oil pumping channel where the channel is aligned with the through hole, and a second position where the channel is offset to close the through hole. The inner side wall of the inner tube channel has a slot for rotating the inner tube body circumferentially along the oil pumping channel via a protruding structure.

[0008] The present invention includes a packer and a switch located between two packers. Both the packer and the switch have an oil extraction channel (inner tube channel) that is vertically connected. The switch includes a lower tube body and an inner tube body that is slidably connected to the lower tube body. The side wall of the lower tube body has a through hole that connects the oil extraction channel and the oil layer. The inner tube body has a channel that connects the through hole and the oil extraction channel. The inner tube body has a first position in the circumferential direction of the oil extraction channel that aligns the channel with the through hole, and a second position that offsets the channel from and closes the through hole. The inner side wall of the oil extraction channel of the inner tube body has a slot for rotating the inner tube body circumferentially along the oil extraction channel by means of a protruding structure. The separate design of the lower and inner casings of the switch in this solution facilitates disassembly and installation. When the well conditions are normal, the downhole switch can be controlled by pressurizing and remotely adjusting the layers to achieve intelligent stratified oil production. When the casing experiences severe leakage and pressurization is impossible or the battery is depleted, the switch cannot be pressure-controlled. In such cases, the raised structure can be mechanically rotated circumferentially to align or stagger the through holes of the lower casing and the inner casing to open or close the switch, ensuring its operation and guaranteeing on-site production.

[0009] Furthermore, the inner tube body has an inwardly protruding circumferential platform on its inner circumferential surface, and the inner tube body sits on the upper surface of the platform.

[0010] The inner tube sits on the upper surface of the ring platform of the lower tube, making installation simple and convenient.

[0011] Furthermore, the upper surface of the annular platform of the lower tube and the lower surface of the inner tube that slides in contact with the upper surface of the annular platform are slidably engaged by matching arc grooves and protrusions; the first position and the second position are respectively located at the ends of the slidingly engaged arc grooves and protrusions in two directions of movement.

[0012] The switch is opened or closed by sliding the arc groove and protrusion on the upper surface of the lower tube and the lower surface of the inner tube that slides in contact with the upper surface of the lower tube. The opening or closing of the switch is controlled by mechanically inserting the protrusion into the arc groove and rotating the protrusion to the two stop points of the arc groove. This mechanical method is simple and easy to operate.

[0013] Furthermore, a connecting hole is opened at the corresponding position of the ring platform. When the inner tube is in the first position, the channel connects the through hole and the connecting hole; when the inner tube is in the second position, the connecting hole and the through hole are closed and not connected.

[0014] A connecting hole is made on the ring platform. When the switch is open, the channel connects the through hole and the connecting hole; when the switch is closed, the connecting hole and the through hole are closed and not connected. During the oil production process, when the test instrument is raised or lowered or the oil pumping equipment stops pumping, various sediments will be generated and fall into the lower oil pipe through the central oil pumping channel. This design structure, which opens the connecting hole when in use and closes it when not in use, will not cause the connecting hole to become blocked.

[0015] Furthermore, an upper necking section and a lower necking section are provided at both ends of the slot, which are smoothly transitioned by chamfering; the protruding structure is formed by key teeth with a guide structure at the front end of the key mechanism; the key teeth are set in the countersunk hole of the key mechanism by a compression elastic structure; when the key mechanism passes through the upper necking section or the lower necking section, the upper necking section or the lower necking section presses the key teeth into the countersunk hole against the elastic force through the guide structure, so as to generate resistance for judging whether the key teeth enter or leave the corresponding inner tube slot; when the key mechanism rotates, the inner tube rotates between the first position and the second position through the mutual cooperation between the key teeth and the slot.

[0016] Upper and lower necking sections are set at both ends of the slot. The protruding structure is formed by key teeth with a guide structure on the key mechanism. The key teeth are set in the countersunk holes on the key mechanism through a compression elastic structure. When the guide structure on the key teeth passes through the upper and lower necking sections, it will perform an extension and retraction action. Each time the key teeth retract and extend, the load on the pipe column received by the ground changes once. This is used to determine whether the key mechanism is descending into or out of the inner pipe body. This determination method is simple and easy to operate.

[0017] Furthermore, the inner circumferential surface of the upper end of the inner tube is provided with internal teeth, which mesh with the external teeth of the connecting rod, and the connecting rod is driven by a motor.

[0018] The mechanical connection structure of the toothed connection is simple, easy to disassemble and flexibly assembled.

[0019] Furthermore, the switch also includes an upper connector with a circumferentially oriented inner hole, a necked step formed on the inner circumferential surface of the upper connector, and the motor is disposed at a corresponding position on the upper end face of the necked step.

[0020] The switch is also equipped with an upper connector, on which the motor is installed. Since the necking step is located on one side of the central oil extraction channel, it does not occupy the position of the oil extraction channel, thus saving installation space.

[0021] Furthermore, the necked step is equipped with pressure sensors for detecting pressure on the inner and outer sides of the tubing, and the pressure sensors are connected to the controller.

[0022] Furthermore, a one-way valve is provided inside the connecting hole.

[0023] One-way valves prevent impurities and sediments in the oil extraction channel from flowing back into the oil layer and contaminating it.

[0024] Furthermore, the motor, controller, and battery for powering the motor and controller are all sealed and mounted on the upper end face of the necked step.

[0025] Sealing the motor, controller, and battery on the upper surface of the constricted step prevents them from being damaged by oil contamination. Attached Figure Description

[0026] Figure 1 This is a tubing diagram of the stratified oil recovery process of the present invention;

[0027] Figure 2 This is a structural diagram of the key mechanism of the present invention;

[0028] Figure 3 This is a structural diagram of the intelligent switch of the present invention;

[0029] Figure 4 This is a structural diagram of the lower tube body of the present invention;

[0030] Figure 5 This is a cross-sectional view of the vertical groove structure of the present invention;

[0031] Figure 6 This is a diagram showing the relative positions of the lower tube and the inner tube when the intelligent switch of the present invention is turned off;

[0032] Figure 7 This is a diagram showing the relative positions of the lower tube and the inner tube when the intelligent switch of the present invention is turned on;

[0033] Figure 8 This is a process flow diagram of the present invention;

[0034] In the diagram: 1. Oil pipe; 2. Pump; 3. Screen pipe; 4. Key mechanism; 41. Main body; 42. Countersunk hole; 43. Key tooth; 44. Spring; 5. Packer; 6. Intelligent switch; 61. Upper connector; 62. Drive structure; 6201. Battery; 6202. Controller; 6203. Pressure sensor; 6204. Mounting hole; 6205. Motor; 6206. Pressure sensor; 6207. Mounting hole; 62 08. Mounting hole; 6209. Coupling; 6210. Connector; 63. Lower tube body; 6301. Through hole; 6302. Arc groove; 6303. Threaded hole; 64. Connecting rod; 65. Inner tube body; 6501. Upper necking section; 6502. Vertical groove; 6503. Lower necking section; 6504. Channel; 6505. Arc boss; 67. Check valve; 7. Packer; 8. Intelligent switch; 9. Plug. Detailed Implementation

[0035] To make the objectives, technical solutions, and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments.

[0036] An example of a tubing string for a stratified oil recovery process:

[0037] like Figure 1 The diagram shows a stratified oil recovery process tubing, including a production tubing and a drop tubing.

[0038] Specifically, such as Figure 1 The production tubing shown includes, from top to bottom, an oil pipe 1, a pump 2, a screen pipe 3, and a key mechanism 4, all connected by threads. (Example) Figure 2 As shown, the key mechanism 4 includes a cylindrical body 41. The upper end of the body 41 is threaded to the screen tube 3, and the lower end of the body 41 is spherical. A countersunk hole 42 is provided circumferentially on the lower part of the cylinder of the body 41. One end of the spring 44 is fixed in the countersunk hole 42 along the radial direction, and the other end of the spring 44 is fixedly connected to the key tooth 43. The key tooth 43 is a cuboid, and its outer end extending out of the countersunk hole 42 is spherical, while its inner end is fixedly connected to the spring 44.

[0039] In this embodiment, the lower end of the main body 41 is a spherical surface, or it can be a tapered surface, trapezoidal surface, or other downward-contracting inclined surface with a guiding function. The outer end of the key tooth 43 is a spherical surface, or it can be a narrow-at-the-bottom, wide-at-the-top inclined surface with a guiding function.

[0040] Specifically, such as Figure 1 The drop-out tubing shown includes packer 5, smart switch 6, packer 7, smart switch 8, and plug 9, which are connected in sequence by threads.

[0041] like Figure 3As shown, the intelligent switch 6 includes an upper connector 61, a lower tube 63 threadedly connected to the lower end of the upper connector 61, and a drive structure 62 installed in the upper connector 61.

[0042] The upper connector 61 has a central channel (inner hole) extending vertically through it, and a necked step in its middle. The necked step has a mounting hole 6208 extending vertically through it. The coupling 6209 is placed in the mounting hole 6208. The inner side of the necked step has a mounting hole 6204, and the pressure sensor 6203 is placed in the mounting hole 6204. The outer side of the necked step has a mounting hole 6207, and the pressure sensor 6206 is placed in the mounting hole 6207. The drive structure 62 is mounted on the upper end face of the step. The upper connector 61 also has an upper connecting end and a lower connecting end.

[0043] The drive structure 62 includes a motor 6205 mounted on the upper end face of the necked step in the middle of the upper connector 61. The drive structure 62 also includes a battery 6201, a controller 6202, and a connector 6210. The controller 6202 is connected to the battery 6201, pressure sensor 6203, pressure sensor 6206, motor 6205, and connector 6210 via control lines.

[0044] The motor 6205 has a connecting shaft at its lower part, through which the motor 6205 is connected to the coupling 6209.

[0045] The lower tube body 63 has a central oil extraction channel extending vertically through it. The lower tube body 63 is equipped with an upper connecting end and a lower connecting end, the upper connecting end of which connects to the lower connecting end of the upper connector 61. The lower tube body 63 also has a necking section (annular platform) inside. Figure 4 The upper end face of the constricted section of the lower tube body 63 shown is provided with a threaded hole 6303 (connecting hole), and a one-way valve 67 is placed in the threaded hole 6303. An arc groove 6302 is provided on the inner side of the upper end face of the constricted section. A through hole 6301 connecting the inner and outer sides of the lower tube body 63 is opened near the constricted section. The inner tube body 65 sits on the upper end face inside the lower tube body 63.

[0046] The inner tube body 65 has a central channel (inner tube channel) extending vertically through it. The inner side of the lower end face of the inner tube body 65 has an arc-shaped boss 6505 (protrusion), which is placed in an arc-shaped groove 6302. The lower end of the inner tube body 65 has a bent channel 6504 for connecting the through hole 6301 and the oil extraction channel. The channel 6504 penetrates the lower end face of the inner tube body 65. The inner side of the central channel at the lower part of the inner tube body 65 has an arc-shaped upper necking section 6501 and a lower necking section 6503. A vertical groove 6502 (groove opening) is provided between the upper necking section 6501 and the lower necking section 6503. The two ends of the vertical groove 6502 smoothly transition to the upper and lower necking sections through chamfers. The inner side of the upper part of the inner tube body 65 has internal teeth, which are engaged with the teeth of the connecting rod 64 with external teeth at the lower part.

[0047] The upper end of the connecting rod 64 is connected to the coupling 6209 via a connecting shaft located at the lower part of the motor 6205.

[0048] The process of using the stratified oil production tubing of this invention is as follows: Figure 8 As shown, the specific workflow is as follows:

[0049] When the stratified oil production tubing of this invention is operating under normal pressure and with normal battery power, if it is necessary to open or close the water-blocking device, the drive structure 62 receives the signal and starts to operate, driving the inner tube 65 to rotate accordingly via the connecting rod 64. The central channel provides a passage for various testing instruments to pass through the water-blocking device. The one-way valve 67 is located at the lower part of the lower tube 63. Various sediments generated when the testing instruments are raised or lowered or when the oil pumping equipment stops pumping fall into the lower oil pipe through the central channel without causing channel blockage. The drive structure 62 is located in a sealed control compartment, which can prevent the drive structure 62 from being contaminated by oil and damaged. At the same time, it can be connected to the drive structure 62 via a cable delivery tool. Without moving the tubing, the connector 6210 can read the data in the controller 6202 and determine the remaining battery power.

[0050] Specifically, the controller 6202 can receive instructions from two aspects: First, before the device enters the well for operation, a periodic opening and closing instruction is pre-set in the controller 6202, and the controller 6202 will perform opening and closing actions at specified time nodes according to this instruction; Second, when the surface injects liquid to pressurize the well, the pressure sensor 6203 receives the pressure change in the central tube during the process. When the pressure exceeds the set pressure threshold, the controller 6202 judges the length of the overpressure period and performs opening or closing actions.

[0051] When encountering severe bushing leakage or battery depletion, making pressure control impossible, the production tubing is lowered, causing the key mechanism 4 to move downwards. Passing through the central tube within the packer 5 and the central tube within the intelligent switch 6, it reaches and passes through the upper constriction section 6501. During this process, the key teeth 43 slide against the upper constriction section 6501 via their guiding spherical end, causing the key teeth 43 to retract and then extend once. The ground receives the tubing load, resulting in a pressure change from pressurization to depressurization. Figure 5 As shown, the key mechanism 4 enters the inner tube 65. At this time, the oil pipe is rotated clockwise to make the key teeth 43 enter the vertical groove 6502. Continue to rotate, as... Figure 6As shown, the arc-shaped boss 6505 rotates to the right dead point (second position) of the arc-shaped groove 6302. In this embodiment, the dead point is the end of the arc-shaped groove. At this time, the hole 6504 on the inner tube 65 is offset from the through hole 6301 and threaded hole 6303 on the lower tube 63. After the inner tube 65 rotates, it closes the through hole 6301 and threaded hole 6303, thereby closing the connection between the oil extraction channel and the oil layer of the intelligent switch 6. The ground rotation torque increases, indicating that the intelligent switch 6 is closed. Figure 7 As shown, the arc-shaped boss 6505 rotates to the left dead point (first position) of the arc-shaped groove 6302. At this time, the hole 6504 on the inner tube 65 connects the through hole 6301 and the threaded hole 6303 on the lower tube 63, thereby connecting the oil pumping channel of the intelligent switch 6 with the oil layer's connecting channel. The ground rotation torque increases, and it is determined that the intelligent switch will be turned on.

[0052] In the above process, by controlling the rotation direction of the inner tube 65, the channel 6504 on the inner tube 65 connects the through hole 6301 and the threaded hole 6303 on the lower tube 63, or the control method of the channel 6504 on the inner tube 65 being staggered from the through hole 6301 and the threaded hole 6303 on the lower tube 63 forms a valve core structure. That is, the opening and closing of the intelligent switch is realized by controlling the rotation direction of the valve core structure.

[0053] like Figure 5 As shown, as the oil pipe continues to move downward, during the process of the key structure 4 reaching and passing through the lower necking section 6503, the key tooth 43 slides through the guide contact of the upper necking section 6503 via the spherical end with the guide function, causing the key tooth 43 to retract and then extend once. The ground receives the load of the tubing and undergoes a change from pressurization to depressurization. It is determined that the key mechanism 4 descends and exits the inner tube body 65. Using the same method, the switching action debugging of the next level intelligent switch 8 can be carried out.

[0054] After the target intelligent switch is debugged, the production tubing is lifted. The position of the production tubing can be determined by counting the number of times the necking section is passed during the upward movement of the key mechanism 4. At the same time, when the length of the wellhead tubing is equal to the length of the tubing being lowered and raised, the operation is considered complete and production can be resumed.

[0055] The telescopic function of the key tooth 43 in the key structure 4 can be achieved in a variety of ways, and this embodiment only illustrates one of them.

[0056] The number of downhole strata can be continuously increased by adding packers and smart switches, enabling the subdivided mining of multiple oil layers.

Claims

1. A stratified oil recovery process tubing string, comprising a dropout tubing string, wherein the dropout tubing string includes packers respectively used for sealing positions above and below corresponding oil layers within the casing, and a switch connecting the two packers and the dropout tubing string through a central hole in one of the packers, characterized in that, The switch includes a lower tube body with an axially formed oil extraction channel. A through hole connecting the oil extraction channel and the oil layer is formed on the side wall of the lower tube body. An inner tube body is rotatably fitted onto the inner circumferential surface of the oil extraction channel. The inner tube body has an inner tube channel radially formed for connecting the oil extraction channel. The inner tube body also has a hole connecting the through hole and the oil extraction channel. The inner tube body has a first position aligning the hole with the through hole in the circumferential direction of the oil extraction channel, and a second position offsetting the hole to close the through hole. The inner circumferential surface at the upper end of the inner tube body is provided with internal teeth that mesh with the external teeth of a connecting rod, which is driven by a motor. The inner wall of the inner tube channel is provided with a slot for rotating the inner tube body circumferentially along the oil extraction channel through a protruding structure; the protruding structure is formed by key teeth on the key mechanism; when the key mechanism rotates, the inner tube body is driven to rotate between the first position and the second position through the mutual cooperation between the key teeth and the slot.

2. The stratified oil recovery process tubing according to claim 1, characterized in that, The inner tube body bulges inward on its inner circumferential surface to form a circumferential platform, and the inner tube body sits on the upper surface of the platform.

3. The stratified oil recovery process tubing according to claim 2, characterized in that, The upper surface of the ring of the lower tube and the lower surface of the inner tube that slides in contact with the upper surface of the ring are slidably fitted by matching arc grooves and protrusions; the first position and the second position are respectively located at the ends of the slidingly fitted arc grooves and protrusions in two directions of movement.

4. The stratified oil recovery process tubing according to claim 2 or 3, characterized in that, A connecting hole is opened at the corresponding position of the ring platform. When the inner tube is in the first position, the channel connects the through hole and the connecting hole; when the inner tube is in the second position, the connecting hole and the through hole are closed and not connected.

5. The stratified oil recovery process tubing according to claim 1, characterized in that, At both ends of the slot, there are upper and lower necking sections that are smoothly transitioned by chamfering; the key teeth are set in the countersunk hole on the key mechanism by a compression elastic structure; when the key mechanism passes through the upper or lower necking section, the upper or lower necking section presses the key teeth into the countersunk hole by the guide structure to overcome the elastic force, so as to generate resistance for judging whether the key teeth enter or leave the corresponding inner tube slot.

6. The stratified oil recovery process tubing according to claim 5, characterized in that, The key mechanism includes a cylindrical body, the upper end of which is threaded to a screen tube, the lower end of which is spherical, and the lower part of the cylindrical body is provided with the countersunk hole in the circumferential direction.

7. The stratified oil recovery process tubing according to claim 6, characterized in that, The switch also includes an upper connector with a circumferentially oriented inner hole, a necked step formed on the inner circumferential surface of the upper connector, and the motor is disposed at a corresponding position on the upper end face of the necked step.

8. The stratified oil recovery process tubing according to claim 7, characterized in that, The necked step is equipped with pressure sensors for detecting pressure on the inner and outer sides of the tubing, and the pressure sensors are connected to a controller that controls the motor.

9. The stratified oil recovery process tubing according to claim 4, characterized in that, A one-way valve is installed inside the connecting hole.

10. The stratified oil recovery process tubing according to claim 8, characterized in that, The motor, controller, and battery for powering the motor and controller are all sealed and mounted on the upper end face of the necked step.

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