A layered water injection device for an oilfield injection well

Abstract

The application provides a layered water injection device for an oilfield injection well, wherein a measuring and adjusting instrument is mounted on a water injection traction device. The traction device comprises a machine body pulled by a cable, a walking mechanism at the bottom, a driving mechanism in the interior and an anchoring mechanism at the top. The walking mechanism comprises a crawling member and a roller member. The driving mechanism drives a first hydraulic cylinder through hydraulic driving, and converts linear motion into rotation through a conversion assembly to drive the crawling member. The device is also provided with a positioning module for downhole positioning in cooperation with the cable. The above technical scheme effectively solves the problem that the measuring and adjusting instrument cannot independently travel to the position in the high-inclination / horizontal well in the prior art. After reaching the position, the anchoring improves the stability when adjusting the eccentric water distribution device. The positioning accuracy of the measuring and adjusting instrument is effectively improved. The anchoring mechanism can reduce the probability of being unable to move forward due to buoyancy. The hydraulic driving mode can effectively reduce the sealing cost and improve the pressure resistance and high-temperature resistance compared with directly driving the motor.

Description

Technical Field

[0001] This invention relates to the field of water injection equipment for oilfield water injection wells, and more specifically to a layered water injection device for oilfield water injection wells. Background Technology

[0002] Layered water injection is a key technology for improving the recovery rate of heterogeneous oil reservoirs. Its core lies in separating multiple oil layers vertically using packers and implementing differentiated and precise water injection control for each layer using a water distributor to balance formation pressure. Currently, the widely used layered water injection process is based on an eccentric water distributor. In this process, the water nozzle plugs of the water distributor are located inside the eccentric working cylinder on one side of the tubing, and the water injection volume of each layer is adjusted by changing water nozzles of different orifice diameters. However, adjusting the water nozzles requires specialized operations, namely using steel wire or cables to lower a retrieval tool into the well, retrieve the old plug, and insert a new one. This process is not only costly and time-consuming, but also cannot achieve real-time monitoring and dynamic adjustment of water injection parameters, making it difficult to meet the needs of modern oilfield precision management.

[0003] To improve regulation efficiency, Chinese patent document CN115110930A discloses a downhole monitoring and control instrument and an oilfield stratified water injection device. This technology involves lowering a monitoring and control instrument integrated with an electric push rod and an adjusting rod via a cable, allowing it to connect to an eccentric water distributor downhole, and directly pushing and pulling the water nozzles to change the flow area. This reduces the number of times water can be retrieved and adjusted, thus improving regulation efficiency.

[0004] However, the above technical solutions rely entirely on cables for suspension and positioning. In complex, steep, or even horizontal wells, it is impossible to move forward to the adjustment point. Even if the well is not steep enough to prevent movement by gravity, once the adjustment point is reached, there is a gap between the measuring instrument and the pipe wall, resulting in instability and the need for readjustment or even adjustment failure. Furthermore, judging the position of the measuring instrument solely by the length of the cable below the pipe can lead to inaccurate judgments due to buoyancy and other factors, making it impossible to determine whether the measuring instrument has reached the adjustment point. Summary of the Invention

[0005] The purpose of this invention is to address the shortcomings of the aforementioned technologies by proposing a layered water injection device for oilfield water injection wells. This device aims to solve the problems of being unable to reach the adjustment point in highly inclined and horizontal wells, being unable to accurately determine the position of the measuring instrument, and the instability of the measuring instrument during adjustment.

[0006] This invention provides a layered water injection device for oilfield water injection wells, including a measuring and adjusting instrument for adjusting the position of the water nozzle in the eccentric water distributor to achieve layered water injection, the measuring and adjusting instrument being mounted on a water injection traction device; The water injection traction device includes: The machine body is connected to the measuring and adjusting instrument, and the machine body is pulled by an external cable; The traveling mechanism, connected to the bottom of the machine body, is used to drive the machine body to move within a steeply inclined or horizontal well pipe. The drive mechanism, located inside the machine body, is used to provide power to the walking mechanism; Anchoring mechanism, connected to the top of the aircraft, is used to stabilize the aircraft's attitude during movement and anchor the aircraft after reaching the target position; The positioning module, located inside the machine body, is used in conjunction with external cables to achieve downhole positioning of the machine body.

[0007] Preferably, the walking mechanism includes a crawling component located at the front end of the machine body and a roller component located at the rear end of the machine body in the direction of travel, and the crawling component is connected to the drive mechanism.

[0008] Preferably, the drive mechanism includes a hydraulic drive assembly, which drives the first hydraulic cylinder to move linearly. The movable end of the first hydraulic cylinder is connected to a conversion assembly, which converts the linear reciprocating motion of the first hydraulic cylinder into rotational motion. The rotating side of the conversion assembly is connected to the crawler and drives the crawler to move forward.

[0009] The hydraulic drive assembly includes a sealed cavity, in which a hydraulic pump is installed. The hydraulic pump is connected to a control valve group, which is connected to a first hydraulic cylinder. The hydraulic pump is driven by a motor, which is powered by an external cable.

[0010] The conversion assembly includes a kinematic pair with a switching groove engraved on its surface. The end of the first hydraulic cylinder is clamped in the switching groove. The other end of the kinematic pair is connected to a rotating rod, which is connected to a bevel gear. The rotating rod is connected to the driving wheel of the bevel gear, and the driven wheel of the bevel gear is connected to the rotation drive end of the crawler.

[0011] Preferably, the anchoring mechanism includes an anchor rod, one end of which is hinged to the machine body, the other end of which is located on the side away from the crawler and movably abuts against the pipe wall, the middle section of which is connected to one end of a second hydraulic cylinder, and the other end of the second hydraulic cylinder is connected to a control valve group and to the machine body. An anchor rod is elastically connected to a movable rod at the end furthest from the machine body. The movable rod is connected to a rotating wheel, which contacts the horizontal section of the pipe.

[0012] Preferably, the positioning module includes an attitude sensing unit located inside the machine body for measuring the machine body's attitude angle, a length measuring unit connected to the cable retraction end, and a travel measuring unit installed inside the machine body. The attitude sensing unit, length measuring unit, and travel measuring unit are all communicatively connected to the control unit.

[0013] Preferably, the positioning method for the water injection traction device includes the following steps: S1, Mode Switching: Based on the cable lowering length recorded by the length measuring unit, the well trajectory data pre-stored in the control unit, and the real-time attitude angle of the machine recorded by the attitude sensing unit, it is determined whether the machine has entered a high-angle or horizontal section. When it is determined to have entered, the current cable lowering length is recorded as the crawling starting point, and the machine is controlled to switch from the cable lowering mode to the autonomous crawling mode. S2. Travel and Positioning: In autonomous crawling mode, the current cumulative length of the machine body is calculated in real time based on the crawling starting point, the travel distance of the machine body, and the well trajectory data. S3. Point Judgment: The current cumulative length of the machine body is compared with the target cumulative length of the target working point in the pre-stored well trajectory data to determine whether it has reached the target working point, and the anchoring mechanism is anchored.

[0014] Preferably, in step S1, to determine whether the machine body has entered a high-angle or horizontal section, the cable lowering length and the real-time attitude angle of the machine body that need to be monitored correspond to the well trajectory data.

[0015] Compared with existing technologies, it has the following beneficial effects: This invention provides a stratified water injection device for oilfield water injection wells, with its control instrument mounted on a water injection traction device. The traction device includes a body pulled by a cable, a bottom traveling mechanism, an internal drive mechanism, and a top anchoring mechanism. The traveling mechanism comprises crawling components and roller components. The drive mechanism hydraulically drives a first hydraulic cylinder, and a conversion component converts linear motion into rotation to drive the crawling components. The device also includes a positioning module for working in conjunction with the cable to achieve downhole positioning. Using the above technical solution, 1. Effectively solves the problem in existing technologies where the measuring instrument cannot autonomously travel to its position in high-angle / horizontal wells; 2. Once in place, anchoring improves the stability when adjusting the eccentric water distributor; 3. Effectively improves the positioning accuracy of the measuring instrument; 4. The anchoring mechanism can support the water injection traction device when traveling in a steeply inclined / horizontal well section, reducing the probability of it being unable to move forward due to buoyancy; 5. The use of hydraulic drive can effectively reduce sealing costs and improve pressure resistance and high temperature resistance compared to direct motor drive. Attached Figure Description

[0016] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only preferred embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort. Figure 1This is a schematic diagram of a layered water injection device for oilfield water injection wells according to the present invention; Figure 2 This is a schematic diagram of the eccentric water distributor of the present invention; Figure 3 This is a side view of a layered water injection device for oilfield water injection wells according to the present invention; Figure 4 This is a schematic diagram of the hydraulic drive assembly of the present invention; Figure 5 This is a schematic diagram of the conversion component of the present invention; Figure 6 This is a top view of the conversion component of the present invention; Figure 7 This is a schematic diagram of the positioning module of the present invention; Figure 8 This is a schematic diagram of the positioning method of the present invention.

[0017] In the diagram, the components are: eccentric water distributor - 11; measuring instrument - 12; pipe - 13; body - 2; cable - 21; walking mechanism - 3; crawling component - 31; roller component - 32; drive mechanism - 4; hydraulic drive assembly - 41; sealing cavity - 411; hydraulic pump - 412; control valve group - 413; first hydraulic cylinder - 414; motor - 415; conversion assembly - 42; kinematic pair - 421; switching slot - 422; rotating rod - 423; bevel gear - 424; anchoring mechanism - 5; anchoring rod - 51; second hydraulic cylinder - 52; moving rod - 53; rotating wheel - 54; positioning module - 6; attitude sensing unit - 61; length measuring unit - 62; travel measuring unit - 63; control unit - 64. Detailed Implementation

[0018] To better understand the structure, functional features, and advantages of the present invention, preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings: Example: like Figures 1 to 7 As shown, this invention provides a measuring and adjusting instrument 12 for adjusting the position of the water nozzles in the eccentric water distributor 11 to achieve stratified water injection. The measuring and adjusting instrument 12 is mounted on a water injection traction device. Oilfield water injection is a key secondary oil recovery technology for maintaining formation pressure and improving crude oil recovery. This process divides the target oil layer into several independent water injection sections by deploying multiple packers from top to bottom within the water injection wellbore. At the corresponding position of each water injection section, an eccentric water distributor 11 is installed. The water distributor has an eccentric channel inside, in which replaceable water nozzles are installed. By adjusting the position of the water nozzles, the orifice diameter of the water outlet is adjusted to regulate the water flow rate and water pressure. This achieves the purpose of limiting water injection in high-pressure layers and strengthening water injection in low-pressure layers, thereby balancing inter-layer contradictions and improving water drive efficiency.

[0019] Most existing layered water injection devices are used in vertical wells. However, when encountering thin oil layers that are difficult to extract, or when vertical drilling is restricted by surface structures, lakes, etc., water injection wells can only be designed with a portion of high-angle or even horizontal sections. In this case, the existing adjusting instrument 12 used to adjust the nozzle cannot reach the water injection point located in the high-angle or horizontal section. Therefore, this application proposes a water injection traction device, which includes: The measuring instrument 12 is connected to the machine body 2, and the machine body 2 is pulled by the external cable 21; The traveling mechanism 3 is connected to the bottom of the body 2 and is used to drive the body 2 to move within the inclined or horizontal well pipe 13; The drive mechanism 4 is located inside the body 2 and is used to provide power to the walking mechanism 3; Anchoring mechanism 5, connected to the top of body 2, is used to stabilize the attitude of body 2 during movement and anchor body 2 after reaching the target position; The positioning module 6 is located inside the body 2 and is used in conjunction with the external cable 21 to achieve downhole positioning of the body 2.

[0020] As another embodiment, such as Figures 1 to 6 As shown, the body 2 of this application has a cylindrical structure. In the horizontal section of the water injection well, the side of the pipe through which the walking mechanism 3 drives the body 2 forward via friction is its bottom or end, and the side opposite the bottom is its top. The walking mechanism 3 includes a crawler 31 located at the front end of the body 2 and a roller 32 located at the rear end of the body 2 in the direction of travel. The crawler 31 is connected to the drive mechanism 4. The crawler 31 is a prior art form, i.e., a walking structure such as a mechanical leg. This application uses a multi-link mechanical leg, where a drive center drives the connecting rods to rotate around it, thereby driving other connecting rods to move. Besides the structure shown in the figure, other possible walking structures can also be used depending on the actual situation. The roller 32 is a prior art form. The part of the roller 32 used for rolling consists of two correspondingly arranged rollers and a shaft connecting the rollers. The shaft is rotatably connected to the bottom of the body 2. The reason for designing the crawler component 31 at the front and the roller component 32 at the rear is that: the inner wall of the pipe is not a smooth surface, and there may be deposits, wax, or slight deformation inside the well shaft. The crawler component 31, through its "gripping" gait, can generate greater static friction and normal pressure. The roller component 32 at the rear can reduce frictional resistance during the later stages of movement. Moreover, compared to a design with crawler components 31 at both the front and rear, the machine body 2 is more stable and can reduce pitch and yaw during movement.

[0021] The drive mechanism 4 includes a hydraulic drive assembly 41, which drives a first hydraulic cylinder 414 in linear motion. The movable end of the first hydraulic cylinder 414 is connected to a conversion assembly 42, which converts the linear reciprocating motion of the first hydraulic cylinder 414 into rotational motion. The rotating side of the conversion assembly 42 is connected to a crawler 31 and drives the crawler 31 to move. Due to the confined, high-pressure, and sediment-rich environment of the mine, directly using a motor for drive faces the following difficulties: the motor rotor shaft requires a dynamic seal, which is easily worn and failed under the continuous impact of high-pressure, abrasive sediment-rich fluids, leading to conductive liquid intrusion and short circuits; the motor itself is the main heat source, and the heat generated is limited, easily causing coil overheating and permanent degradation of insulation performance. The underground environment is humid and may contain corrosive media (such as hydrogen sulfide), which will directly corrode the insulation material. Therefore, this application uses a hydraulic drive converted into rotational motion as the driving power.

[0022] The hydraulic drive assembly 41 includes a sealed cavity 411, within which a hydraulic pump 412 is housed. The hydraulic pump 412 is connected to a control valve assembly 413, which is connected to a first hydraulic cylinder 414. The hydraulic pump 412 is driven by a motor 415, which is powered by an external cable 21. The control valve assembly 413 regulates the flow direction, flow rate, and pressure of the hydraulic oil, thereby controlling the extension and retraction speed, direction, and output force of the first hydraulic cylinder 414. The sealed cavity 411 is filled with oil, which itself serves as an excellent cooling medium, facilitating heat dissipation for the motor 415 and hydraulic pump 412 during operation. Heat exchange with external well fluid occurs through the metal wall of the cavity 411, effectively solving the heat dissipation problem. Furthermore, the output end of the motor 415 does not directly contact the external corrosive environment, effectively reducing sealing costs and improving sealing performance. The external cable 21 is connected to the sealed cavity 411 via a high-pressure through-connector, such as a SUBCONN BH8M watertight connector. This connector ensures power transmission while achieving a static seal on the cavity, providing power to motor 415 and enabling possible signal transmission.

[0023] The conversion assembly 42 includes a kinematic pair 421 with a switching groove 422 engraved on its surface. The end of a first hydraulic cylinder 414 is clamped within the switching groove 422. The other end of the kinematic pair 421 is connected to a rotating rod 423, which is connected to a bevel gear 424. The rotating rod 423 is connected to the driving wheel of the bevel gear 424, and the driven wheel of the bevel gear 424 is connected to the rotation drive end of the crawler 31. The switching groove 422 is a continuous wave shape. A clamping part is welded to the end of the hydraulic cylinder 414, and two ends of the clamping part are welded or screwed to a slider, which slides within the switching groove 422. The center of the driving wheel of the bevel gear 424 is aligned with the center of the rotating rod 423 and is connected by welding or nailing. The driven wheel of the bevel gear 424 is a symmetrical gear located on both sides of the driving wheel. The shaft of the driven wheel is welded to the machine body. When the driving wheel rotates, the two driven wheels rotate in opposite directions, causing the crawler 31 connected to the center of the driven wheel to move alternately, thus enabling it to move forward.

[0024] The anchoring mechanism 5 includes an anchoring rod 51. One end of the anchoring rod 51 is hinged to the machine body 2, and the other end of the anchoring rod 51 is located on the side away from the crawler 31 and movably abuts against the pipe wall of the pipe 13. The middle section of the anchoring rod 51 is connected to one end of the second hydraulic cylinder 52, and the other end of the second hydraulic cylinder 52 is connected to the control valve group 413 and the machine body 2. The second hydraulic cylinder 52 is connected to the corresponding control oil port on the control valve group 413 through an oil pipe. When anchoring is required, the control unit 64 controls the second hydraulic cylinder 52 to rise, and the side of the anchoring rod 51 away from the crawler 31 abuts against the pipe wall, so that the anchoring rod 51 and the crawler 31 abut against the pipe wall at symmetrical positions, thereby achieving anchoring and effectively improving the stability of the measuring instrument 12 when adjusting or replacing the water nozzle position.

[0025] Anchor rod 51 is elastically connected to a movable rod 53 at the end furthest from body 2. Movable rod 53 is connected to a rotating wheel 54, which contacts the horizontal section of pipe 13. Movable rod 53 and anchor rod 51 are connected by a torsion spring, or by an arc-shaped elastic telescopic rod. The figure shows the arc-shaped elastic telescopic rod connection.

[0026] The movable rod 53 is designed so that when the machine body 2 travels on a steep incline or horizontal section, the second hydraulic cylinder 52 raises the anchor rod 51 to a certain height, causing the rotating wheel on the movable rod 53 to contact the top of the inner wall of the pipe, thus reducing the probability that the crawler 31 will fail to contact the pipe due to buoyancy. When the pipe is vertical, the second hydraulic cylinder 52 retracts, allowing the machine body 2 to fall along the pipe under its own weight. When the measuring instrument 12 reaches the measuring point, the second hydraulic cylinder 52 rises to its highest position, causing the end of the anchor rod 51 to anchor against the top of the inner wall of the pipe.

[0027] As another embodiment, such as Figure 7As shown, the positioning module 6 of this application includes an attitude sensing unit 61 located inside the body 2 for measuring the attitude angle of the body 2, a length measuring unit 62 connected to the retraction end of the cable 21, and a travel measuring unit 63 installed inside the body 2. The attitude sensing unit 61, the length measuring unit 62 and the travel measuring unit 63 are all communicatively connected to the control unit 64.

[0028] An attitude sensing unit 61 is installed inside the body 2 and is a sensor combination used to measure and determine the angle and orientation of the body 2 in the downhole space. It typically includes a three-axis gyroscope and a three-axis accelerometer. The three-axis gyroscope can calculate the angle change through integration, and the three-axis accelerometer measures the linear acceleration of the body in three directions. In a stationary state, it can measure the direction of the gravity vector, thereby calculating the tilt angle relative to the horizontal plane.

[0029] The length measuring unit 62 is a sensor installed on the ground winch or cable injection device. The principle is that the encoder converts the rotation pulse signal of the measuring wheel into an electrical signal and transmits it to the control unit 64, thereby recording the cable lowering depth in real time.

[0030] The travel measurement unit 63 is installed inside the machine body 2 and is a device that autonomously measures the actual crawling distance of the machine body within the pipeline. This application uses a wheel encoder. It is linked to the driven wheel of the bevel gear 424. Each rotation of the driven wheel of the bevel gear 424 generates a certain number of pulses from the encoder. By counting the number of pulses and multiplying it by the circumference of the wheel, the relative travel distance of the machine body relative to the well shaft can be calculated.

[0031] The attitude sensing unit 61, length measuring unit 62, and travel measuring unit 63 all communicate with the ground control unit 64 through the communication core in the cable, such as RS-485 or Ethernet.

[0032] As another embodiment, such as Figure 8 As shown, the positioning method of the water injection traction device in this application includes the following steps: S1, Mode Switching: Based on the cable 21 lowering length recorded by the length measuring unit 62, the well trajectory data pre-stored in the control unit 64, and the real-time attitude angle of the machine body 2 recorded by the attitude sensing unit 61, it is determined whether the machine body 2 has entered a high-angle or horizontal section. When it is determined to have entered, the current cable 21 lowering length is recorded as the crawling starting point, and the machine body 2 is controlled to switch from the cable 21 lowering mode to the autonomous crawling mode. In step S1, to determine whether the machine body 2 has entered a high-angle or horizontal section, the cable 21 lowering length and the real-time attitude angle of the machine body 2 that need to be monitored are both corresponding to the well trajectory data.

[0033] The wellbore trajectory data is a dataset obtained in advance through well logging, describing the spatial morphology of the entire wellbore. Its core is recording the inclination angle and azimuth angle corresponding to each measurement depth. The control unit 64 continuously compares the theoretical inclination angle in the pre-stored wellbore trajectory data corresponding to the cable 21's lowering length with the real-time inclination angle measured by the attitude sensing unit 61. When all three are consistent and the values ​​indicate that the inclination angle is consistently greater than a certain set threshold, such as consistently greater than 60 degrees, it indicates entry into a high-inclination section. This set threshold is a segment of the wellbore trajectory data. It can then be determined that the machine 2 has entered a well section where it cannot be reliably lowered solely by gravity. Upon determination, the lowering length of the cable at this moment is immediately locked and recorded as the depth value of the "crawling starting point." This point is the reference origin for switching from cable 21 suspension positioning to autonomous crawling positioning.

[0034] S2. Travel and Positioning: In autonomous crawling mode, based on the crawling starting point, the travel distance of body 2, and the well trajectory data, the current cumulative length of body 2 is calculated in real time.

[0035] The travel distance is measured by the travel metering unit 63, which records the crawling length of the machine body 2 since the crawling start point. The current cumulative length refers to the theoretical well depth of the current position of the machine body 2, that is, the crawling length plus the length lowered by its own weight. The control unit 64 combines real-time attitude angle and well trajectory data to perform curve integration correction on the crawling path. Because the machine body is crawling in a curved wellbore, simple straight-line accumulation will produce errors. Through the real-time attitude angle, the local well inclination of the current segment can be known, thus more accurately converting it into vertical depth increment or increment along the well inclination trajectory.

[0036] S3. Point Judgment: The current cumulative length of the machine body 2 is compared with the target cumulative length of the target working point in the pre-stored well trajectory data to determine whether it has reached the target working point, and the anchoring mechanism 5 anchors.

[0037] The control unit 64 continuously calculates the current cumulative length and compares it in real time with the target cumulative length of the pre-marked target working point in the well trajectory data. When the difference between the current cumulative length and the target cumulative length falls within a preset allowable error range (e.g., ±0.1 meters), the system determines that the machine body 2 has reached the target working point. The control unit 64 controls the anchoring mechanism 5 to move, fixing the machine body 2 to the well wall, forming a stable working platform. Subsequently, the measuring and adjusting instrument 12 is started to adjust the water injection volume.

[0038] This application discloses the working principle of a stratified water injection device for oilfield water injection wells: The adjusting instrument 12, used to adjust the nozzle of the eccentric water distributor 11, is integrated into a traction device with autonomous movement capability. The core of this device is the body 2, which contains a drive mechanism 4. By enclosing the motor 415 and hydraulic pump 412 within a sealed cavity 411, the sealing and heat dissipation of the motor 415 downhole are improved. The generated power drives the crawling component 31 at the front end, achieving reliable traction downhole at high angles / horizontal depths. Simultaneously, an anchoring mechanism 5 is provided at the top of the device to stabilize the operating posture, and a positioning module 6 is equipped to integrate multi-source information for precise positioning.

[0039] The positioning process consists of three steps. Mode switching: By comparing cable depth, real-time machine posture, and pre-stored well trajectory data, the system automatically identifies the starting point of a steep well section and switches to autonomous crawling mode. Travel positioning: Using the switching point as a reference, and combining the machine's own odometer data, the system calculates and updates its precise position within the wellbore in real time. Point judgment and anchoring: The calculated position is compared with the target point depth. Upon arrival, the anchoring mechanism is immediately activated to lock the machine, providing a stable operating platform for the measuring and adjusting instrument, thereby completing the fine adjustment of stratified water injection.

[0040] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention in any way. Any person skilled in the art can make many possible variations and modifications to the technical solutions of the present invention, or modify them into equivalent embodiments, without departing from the scope of the present invention. Therefore, any modifications, equivalent changes, and alterations made to the above embodiments based on the technology of the present invention without departing from the scope of the present invention are within the protection scope of the present invention.

Claims

1. A stratified water injection device for oilfield water injection wells, comprising a measuring and adjusting instrument (12) for adjusting the position of the water nozzle in the eccentric water distributor (11) to achieve stratified water injection, characterized in that, The measuring instrument (12) is mounted on the water injection traction device; The water injection traction device includes: The machine body (2) is connected to the measuring instrument (12), and the machine body (2) is pulled by an external cable (21); The walking mechanism (3) is connected to the bottom of the body (2) and is used to drive the body (2) to move in a steeply inclined or horizontal well pipe (13); A drive mechanism (4) is disposed inside the body (2) and is used to provide power to the walking mechanism (3); An anchoring mechanism (5) is connected to the top of the body (2) and is used to stabilize the attitude of the body (2) during travel and anchor the body (2) after reaching the target position. The positioning module (6) is located inside the body (2) and is used to work with the external cable (21) to achieve the downhole positioning of the body (2).

2. The layered water injection device for oilfield water injection wells according to claim 1, characterized in that, The walking mechanism (3) includes a crawling component (31) located at the front end of the body (2) and a roller component (32) located at the rear end of the body (2) in the direction of travel. The crawling component (31) is connected to the driving mechanism (4).

3. The layered water injection device for oilfield water injection wells according to claim 2, characterized in that, The drive mechanism (4) includes a hydraulic drive assembly (41), which drives the first hydraulic cylinder (414) to move linearly. The movable end of the first hydraulic cylinder (414) is connected to a conversion assembly (42), which converts the linear reciprocating motion of the first hydraulic cylinder (414) into rotational motion. The rotating side of the conversion assembly (42) is connected to the crawler (31) and drives the crawler (31) to move.

4. The layered water injection device for oilfield water injection wells according to claim 3, characterized in that, The hydraulic drive assembly (41) includes a sealed cavity (411) in which a hydraulic pump (412) is installed. The hydraulic pump (412) is connected to a control valve group (413), which is connected to a first hydraulic cylinder (414). The hydraulic pump (412) is driven by a motor (415), which is powered by the external cable (21).

5. The layered water injection device for oilfield water injection wells according to claim 4, characterized in that, The conversion assembly (42) includes a kinematic pair (421) with a switching groove (422) engraved on its surface. The end of the first hydraulic cylinder (414) is clamped in the switching groove (422). The other end of the kinematic pair (421) is connected to a rotating rod (423). The rotating rod (423) is connected to a bevel gear (424). The rotating rod (423) is connected to the driving wheel of the bevel gear (424). The driven wheel of the bevel gear (424) is connected to the rotation drive end of the crawler (31).

6. The layered water injection device for oilfield water injection wells according to claim 5, characterized in that, The anchoring mechanism (5) includes an anchor rod (51), one end of which is hinged to the body (2), and the other end of which is located away from the crawler (31) and movably abuts against the wall of the pipe (13). The middle section of the anchor rod (51) is connected to one end of the second hydraulic cylinder (52), and the other end of the second hydraulic cylinder (52) is connected to the control valve group (413) and to the body (2). An anchor rod (51) is elastically connected to a movable rod (53) at one end away from the body (2). The movable rod (53) is connected to a rotating wheel (54), and the rotating wheel (54) contacts the horizontal section of the pipe (13).

7. The layered water injection device for oilfield water injection wells according to claim 1, characterized in that, The positioning module (6) includes an attitude sensing unit (61) located inside the body (2) for measuring the attitude angle of the body (2), a length measuring unit (62) connected to the retraction end of the cable (21), and a travel measuring unit (63) provided inside the body (2). The attitude sensing unit (61), the length measuring unit (62) and the travel measuring unit (63) are all communicatively connected to the control unit (64).

8. A positioning method for a water injection traction device, characterized in that, The positioning method using the water injection traction device according to any one of claims 1-7 includes the following steps: S1, Mode Switching: Based on the length of the cable (21) lowered by the length measuring unit (62), the well trajectory data pre-stored in the control unit (64), and the real-time attitude angle of the machine body (2) recorded by the attitude sensing unit (61), it is determined whether the machine body (2) has entered a large slope or horizontal section. When it is determined to have entered, the current length of the cable (21) lowered is recorded as the crawling starting point, and the machine body (2) is controlled to switch from the cable (21) lowering mode to the autonomous crawling mode. S2, Travel and Positioning: In autonomous crawling mode, based on the crawling starting point, the travel distance of the machine body (2) and the well trajectory data, the current cumulative length of the machine body (2) is calculated in real time; S3. Point determination: The current cumulative length of the machine body (2) is compared with the target cumulative length of the target working point in the well trajectory data to determine whether it has reached the target working point, and the anchoring mechanism (5) is anchored.

9. The positioning method for the water injection traction device according to claim 8, characterized in that, In step S1, it is necessary to determine whether the machine body (2) has entered a large inclination or horizontal section. The length of the cable (21) that needs to be lowered and the real-time attitude angle of the machine body (2) are both corresponding to the well trajectory data.

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