Electric bailing tool and bailing method thereof

Abstract

The invention provides an electric sand bailing tool and a sand bailing method thereof, and belongs to the technical field of oil production engineering.The sand bailing tool comprises a shell, a conveying mechanism, a stirring mechanism and a sand storage mechanism; the shell is provided with a liquid inlet and a liquid outlet, the conveying mechanism is located on the upper portion of the shell, the stirring mechanism is located on the lower portion of the shell, the sand storage mechanism is located in the middle of the shell, the conveying mechanism comprises a first driving module and a sand pump, the stirring mechanism comprises a second driving module and rotating blades, and the sand storage mechanism comprises a sand baffle and a sand storage cylinder. A sand storage cavity used for storing sand is formed between the center pipe and the outer cylinder, and a circulation channel allowing sand mixing liquid to flow upwards is formed in the center pipe. By means of the sand bailing tool, sand bailing work of a deep well and a low-pressure well can be achieved, the sand bailing efficiency is high, the construction period is short, and the operation cost is low.

Description

Technical Field

[0001] The present invention relates to the technical field of oil production engineering, and in particular, to an electric sand fishing tool and a sand fishing method for an electric sand fishing tool. Background Art

[0002] Sand cleaning operation is a common operation process in downhole operations. Usually, the circulating sand washing method or the sand fishing method is used to clean the bottom sand in the wellbore and restore the normal production of oil and water wells.

[0003] Currently, there are two common methods for removing sand deposits in the wellbore. One sand cleaning method is circulating sand washing, which is also the most widely used sand cleaning method in domestic oilfields. That is, by means of a pump truck to circulate the liquid, the sand deposits in the well are carried to the ground. The main disadvantages of this method are as follows: First, it requires sand washing fluid and a pump truck, resulting in high construction costs; second, when sand washing in deep wells, large casing wells, and composite casing wells, it is difficult for the sand to return to the ground, and sand sticking accidents are likely to occur during construction, and the construction time is long; third, when sand washing in low-pressure wells and lost circulation wells, it is difficult for the sand washing fluid to return to the wellhead, and the sand washing fluid and formation sand will leak into the formation, damaging the oil layer, thereby increasing the difficulty of liquid drainage and production. Moreover, sand sticking is likely to occur during sand washing, and in order to achieve the purpose of sand washing, temporary plugging needs to be carried out before sand washing. The temporary plugging agent belongs to a polymer, and there are also problems such as oil layer pollution and increased construction costs.

[0004] Another sand cleaning method is the sand fishing method, that is, the sand fishing tool is sent into the well through the tubing or wire rope. The ground operator repeatedly lifts and lowers the sand fishing tool to strike the sand surface, and the deposited sand is sucked into the pump and stored in the sand storage cylinder to achieve sand fishing. Its main disadvantages are: First, the amount of sand fished each time is limited, and if there is too much deposited sand in the well, multiple sand fishing operations are required; second, for tubing sand fishing, the pipe string load is heavy, and the construction safety risk in deep wells is high, and it is only applicable to shallow wells; third, the requirements for the use environment and working conditions are harsh, and the wire rope is prone to structural damage, affecting its actual use performance and service life. Summary of the Invention

[0005] Aiming at the technical problems of low operation efficiency and difficult sand cleaning in low-pressure wells and deep wells existing in the conventional sand fishing process in the prior art, the present invention provides an electric sand fishing tool and a sand fishing method thereof. Using this sand fishing tool can improve the sand fishing efficiency, shorten the construction period, and reduce the operation cost.

[0006] To achieve the above object, on the one hand, the present invention provides an electric sand fishing tool, which includes: a conveying mechanism, a stirring mechanism and a sand storage mechanism; the housing is a hollow cylinder, and inside the housing there are a first cavity, a second cavity and a third cavity connected in sequence along the direction from the ground to the well bottom, and a liquid inlet is provided at the bottom of the third cavity, and a liquid outlet is provided at the top or side of the first cavity; the conveying mechanism is located in the first cavity, the stirring mechanism is located in the third cavity, and the sand storage mechanism is located in the second cavity; the conveying mechanism includes a first driving module and a sand pumping pump, the first driving module is connected to the sand pumping pump and is used to provide driving force for the sand pumping pump, and the sand pumping pump is used to convey the sand-mixed liquid from the liquid inlet of the third cavity to the liquid outlet of the first cavity; the sand storage mechanism includes a sand storage cylinder and a sand baffle, the sand storage cylinder includes: an outer cylinder and a central tube, the central tube is arranged inside the outer cylinder, and a sand storage cavity capable of storing sand is formed between the central tube and the outer cylinder, and a circulation channel for the sand-mixed liquid to flow upward is formed inside the central tube, and the sand baffle is arranged directly above the circulation channel and is used to change the flow rate and flow direction of the sand-mixed liquid; the stirring mechanism includes a second driving module and a rotating blade, the second driving module is connected to the rotating blade and is used to provide driving force for the rotating blade, and the rotating blade is used to stir the sand-mixed liquid in the well.

[0007] In an exemplary embodiment of the present invention, a filter screen is provided between the sand pumping pump and the sand baffle.

[0008] In an exemplary embodiment of the present invention, a filter screen may be provided at the bottom of the outer cylinder.

[0009] In an exemplary embodiment of the present invention, a plurality of centralizing blocks may be provided between the outer cylinder and the central tube.

[0010] In an exemplary embodiment of the present invention, the sand storage cylinder may be prepared from an alloy material.

[0011] In an exemplary embodiment of the present invention, the alloy material may be aluminum alloy.

[0012] In an exemplary embodiment of the present invention, the sand baffle may be an arc-shaped structure.

[0013] In an exemplary embodiment of the present invention, the sand baffle may be an inverted V-shaped structure.

[0014] In an exemplary embodiment of the present invention, the rotating blade may be a spiral structure.

[0015] In an exemplary embodiment of the present invention, a first speed reducer assembly may be provided between the first driving module and the sand pumping pump.

[0016] In an exemplary embodiment of the present invention, a second speed reducer assembly may be provided between the second drive module and the rotary blade.

[0017] In an exemplary embodiment of the present invention, the sand fishing tool may further include: a downhole control mechanism and a ground control terminal; the ground control terminal is configured to send a control instruction to the downhole control mechanism, and the downhole control mechanism is configured to control the first drive module and the second drive module in response to the control instruction.

[0018] In an exemplary embodiment of the present invention, the ground control terminal may be connected to the downhole control mechanism through a cable, and the downhole control mechanism may be connected to the housing through a cable.

[0019] In an exemplary embodiment of the present invention, a safety pin may be provided at the connection between the housing and the cable.

[0020] In an exemplary embodiment of the present invention, a fishing structure may be provided at the upper end of the housing.

[0021] On the other hand, the present invention provides a sand fishing method for an electric sand fishing tool, which is implemented by the above-mentioned electric sand fishing tool, and includes the following steps: lowering the sand fishing tool to the downhole; when the sand fishing tool contacts the sand surface, starting the sand pumping pump and the rotary blade, stirring the bottom sediment in the well bottom by the rotary blade to form a sand-mixed liquid, the sand-mixed liquid enters the housing from the liquid inlet and flows upward under the suction of the sand pumping pump, when the sand-mixed liquid reaches the baffle plate, the sand in the sand-mixed liquid is separated from the liquid flow, the sand settles downward into the sand storage cylinder for storage, and the liquid flow continues to flow upward to the sand pumping pump and is discharged from the liquid outlet to the wellbore; after the fishing is completed, lifting out the sand fishing tool and discharging the sand in the sand storage cylinder.

[0022] In another exemplary embodiment of the present invention, the sand fishing tool may be lowered to the downhole through a rope, and the rope is a cable or a steel wire rope.

[0023] In another exemplary embodiment of the present invention, the sand fishing tool may be lowered to the downhole through a coiled tubing.

[0024] In another exemplary embodiment of the present invention, the sand fishing method may further include: during the process of lowering the sand fishing tool, judging whether the sand fishing tool contacts the sand surface based on the change in the tension of the rope.

[0025] In another exemplary embodiment of the present invention, the sand fishing method may further include: before lowering the sand fishing tool, presetting the working time of the second drive module based on the well depth and the lowering speed of the sand fishing tool.

[0026] Through the technical solution provided by the present invention, the present invention has at least the following technical effects:

[0027] (1) By combining the flow characteristics of solids and liquids in the sand mixing fluid, the present invention realizes fishing out the bottom-hole sand deposits and storing them in the sand storage cylinder by using structures such as a sand pump, a rotating blade, a sand storage cylinder, and a sand baffle, etc., solving the problems of limited single-time sand fishing amount and low sand fishing efficiency of traditional sand fishing tools, and providing a new means for sand fishing and salvage in oil and gas wells;

[0028] (2) The electric sand fishing tool provided by the present invention lowers the tool and transmits signals through a cable, which can effectively solve the problem of difficult sand cleaning in low-pressure wells and deep wells;

[0029] (3) The electric sand fishing tool provided by the present invention has the advantages of fast tripping speed, high sand fishing efficiency, and low operation cost.

[0030] Other features and advantages of the present invention will be described in detail in the subsequent specific implementation section. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] The drawings are used to provide a further understanding of the embodiments of the present invention, and constitute a part of the specification. Together with the following specific implementation, they are used to explain the embodiments of the present invention, but do not constitute a limitation to the embodiments of the present invention. In the drawings:

[0032] Figure 1 is a schematic diagram of the components of the electric sand fishing tool provided by the embodiment of the present invention;

[0033] Figure 2 is a schematic diagram of the connection sequence of the downhole tool string provided by the embodiment of the present invention;

[0034] Figure 3 is a schematic diagram of the structure of the electric sand fishing tool provided by the embodiment of the present invention;

[0035] Figure 4 is a schematic diagram of the structure of the sand storage cylinder provided by the embodiment of the present invention;

[0036] Figure 5 is a schematic diagram of the structure of the centralizer provided by the embodiment of the present invention;

[0037] Figure 6 is a schematic diagram of the structure of the sand filter screen provided by the embodiment of the present invention;

[0038] Figure 7 is a schematic diagram of the structure of the stirring mechanism provided by the embodiment of the present invention;

[0039] Figure 8 is a schematic diagram of the operation process of the electric sand fishing tool provided by the embodiment of the present invention.

[0040] DESCRIPTION OF THE REFERENCE NUMERALS

[0041] 1 - housing, 2 - first motor, 3 - sand pumping pump, 4 - sand baffle, 5 - sand storage cylinder, 51 - outer cylinder, 52 - centralizer, 53 - central pipe, 6 - second motor, 7 - spiral blade, 8 - output shaft, 9 - motor base, 10 - centralizer, 11 - sand filter screen. Detailed implementation manners

[0042] The following will describe in detail the specific implementation manners of the embodiments of the present invention with reference to the accompanying drawings. It should be understood that the specific implementation manners described herein are only used to illustrate and explain the embodiments of the present invention, and are not used to limit the embodiments of the present invention.

[0043] It should be noted that, without conflict, the embodiments in the present invention and the features in the embodiments can be combined with each other.

[0044] In the present invention, unless otherwise stated, the orientation words such as "upper, lower, top, bottom" are usually in the direction shown in the accompanying drawings or in the vertical, perpendicular or gravitational direction for describing the relative positional relationship of each component. "First", "second", etc. are only for convenience of description and easy distinction, and cannot be understood as indicating or implying relative importance.

[0045] In the description of the present invention, it should also be noted that, unless otherwise clearly specified and limited, the terms "installation", "connection", etc. should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a direct connection, or an indirect connection; it can be a wired connection, or a wireless connection. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific situations.

[0046] Aiming at the technical problems existing in the conventional sand fishing process, such as long operation time and low sand fishing efficiency, the present invention proposes an electric sand fishing tool and its sand fishing method. The sand fishing tool can stir up the bottom sediment through a sand pumping pump and a rotating blade and transport it into the circulation channel inside the tool. When the sand - mixed liquid reaches the upper sand baffle, the circulation channel becomes larger and the flow velocity of the sand - mixed liquid becomes smaller. At this time, the sand in the sand - mixed liquid falls into the sand storage cylinder for storage because the sedimentation speed is greater than the upward return speed, while the liquid flow in the sand - mixed liquid continues to flow upward into the impeller of the sand pumping pump under the suction of the sand pumping pump and finally is discharged from the liquid discharge port above the tool into the wellbore to complete the circulating flow process of the liquid flow. The sand fishing tool is ingeniously designed, small in volume, flexible and convenient to operate. The sand fishing tool can be lowered to the bottom of a deep well through a cable, and the sand fishing tool can be controlled by a ground control terminal to complete the sand fishing work. In this way, it can not only effectively solve the problem of difficult sand cleaning in low - pressure wells and deep wells, but also improve the construction efficiency and reduce the labor intensity of the operation.

[0047] The technical solution of the present invention will be described in detail below with reference to the accompanying drawings and in conjunction with embodiments. The following several specific embodiments can be combined with each other, and the same or similar concepts or processes may not be repeated in some embodiments.

[0048] In one aspect, an embodiment of the present invention provides an electric sand fishing tool, which may include: a housing, a conveying mechanism, a stirring mechanism, and a sand storage mechanism.

[0049] The housing is a hollow cylinder, and inside the housing, there are a first cavity, a second cavity, and a third cavity connected in sequence along the direction from the ground to the wellbore. A liquid inlet is provided at the bottom of the third cavity, and a liquid outlet is provided at the top or side of the first cavity. A connection port is provided at the top of the housing for connecting with a cable, a wire rope, or a coiled tubing to realize the lowering and retrieving of the sand fishing tool. Additionally, the housing can be cylindrical, or it can be cuboid-shaped, prism-shaped, etc., as long as the shape and size of the housing can meet the sand fishing requirements for lowering into the wellbore.

[0050] The first cavity is used to arrange the conveying mechanism, the second cavity is used to arrange the sand storage mechanism, and the third cavity is used to arrange the stirring mechanism. The bottom of the well is filled with sediment and circulating liquid. When the sand fishing tool is lowered into the well, the stirring mechanism is used to stir the sediment at the bottom of the well and the circulating liquid into a sand-mixed liquid, the conveying mechanism is used to pump the sand-mixed liquid at the bottom of the well from the liquid inlet of the third cavity and discharge it from the sand-mixed liquid outlet of the first cavity, and the sand storage mechanism is used to automatically separate the liquid flow and sand in the sand-mixed liquid during the upward transportation of the sand-mixed liquid and store the sand to complete sand fishing.

[0051] Specifically, the conveying mechanism includes a first driving module and a sand pump. The first driving module is connected to the sand pump and is used to provide driving force to the sand pump. The sand pump is used to convey the sand-mixed liquid from the liquid inlet of the third cavity to the liquid outlet of the first cavity.

[0052] The sand storage mechanism includes a sand storage cylinder and a sand baffle. The sand storage cylinder consists of an outer cylinder and a central pipe. Among them, the outer cylinder is a hollow cylinder with an open upper end and a closed lower end, and the central pipe is a hollow cylinder with open upper and lower ends and is arranged inside the outer cylinder. At this time, an annular space can be formed between the outer wall of the central pipe and the inner wall of the outer cylinder, and this annular space can be used as a sand storage cavity for storing reservoir sand, while the internal channel of the central pipe can be used as a circulation channel for the sand mixing liquid to flow upward. The sand baffle can be arranged directly above the central pipe and is used to change the flow rate and flow direction of the sand mixing liquid after it flows upward out of the circulation channel. That is to say, when the sand mixing liquid flows out of the circulation channel in the central pipe and reaches the sand baffle, the setting of the sand baffle blocks the upward flow direction of the sand mixing liquid, causing the sand mixing liquid to start flowing along the perimeter of the sand baffle. At this time, the flow channel of the sand mixing liquid becomes larger, the flow rate of the sand mixing liquid slows down, and the sand in the sand mixing liquid will fall into the sand storage cavity because the sedimentation speed is greater than the upward flow speed of the liquid flow, while the liquid flow in the sand mixing liquid continues to flow upward along the perimeter of the sand baffle and into the impeller of the sand extraction pump under the action of the upward flow speed of the liquid flow and the suction pump. In this way, the solid-liquid separation in the sand mixing liquid can be achieved.

[0053] The stirring mechanism includes a second drive module and rotating blades. The second drive module is connected to the rotating blades and is used to provide driving force to the rotating blades, and the rotating blades are used to stir the sand mixing liquid in the wellbore. Since the bottom sediment in the wellbore is prone to phenomena such as sediment caking when it is in a static state for a long time, it is very difficult to effectively use the circulating liquid to carry the sand into the sand fishing tool only through the suction action of the suction pump. Therefore, rotating blades need to be set at the liquid inlet to stir the bottom sediment in the wellbore. The stirred sand mixing liquid is easier to transport, which is beneficial for the suction pump to transport the sand mixing liquid upward to the liquid discharge port to complete the circulating transportation of the sand mixing liquid.

[0054] Furthermore, in a possible implementation manner, a filter screen can be arranged between the sand extraction pump and the sand baffle. In order to ensure the normal operation of the sand extraction pump and extend its service life, a filter screen should be arranged around the impeller of the sand extraction pump to prevent some residual sand in the sand mixing liquid flowing upward to the sand extraction pump from entering the impeller of the sand extraction pump, resulting in damage or failure of the impeller.

[0055] Furthermore, in a possible implementation manner, a filter screen can also be arranged at the bottom of the outer cylinder of the sand storage cylinder. Since it is inevitable that some liquid is carried when the sand falls downward into the sand storage cavity, the filter screen can be set to filter the liquid in the sand storage cavity in time to avoid part of the storage space of the sand storage cavity being occupied.

[0056] Further, in a possible implementation, a plurality of centralizing blocks may be arranged in the annular space between the outer wall of the central tube and the inner wall of the outer cylinder. The plurality of centralizing blocks are arranged in a certain interval sequence to support and correct the positions of the central tube and the outer cylinder, ensuring that the relative position, angle, and clearance between the central tube and the outer cylinder meet the design requirements. Additionally, in some cases, the centralizing blocks can also be used as buffer materials to reduce vibration and impact, protecting the central tube, the outer cylinder, and other accessory parts from damage.

[0057] Further, in a possible implementation, the sand storage cylinder can be made of alloy material. Since the sand storage cylinder needs to be lowered into the well for a long time, in order to improve the service life of the sand storage cylinder and reduce the labor intensity at the same time, the material for preparing the sand storage cylinder needs to have the characteristics of light weight, high temperature resistance, and corrosion resistance. For example, the alloy material can be aluminum alloy.

[0058] Further, in a possible implementation, the sand baffle can be arranged in an arc structure. Since the surface morphology of the sand baffle has a certain influence on the flow direction of the sand-mixed liquid, by designing the plane of the sand baffle into a certain concave-convex surface, it is beneficial to change the flow direction of the sand-mixed liquid, causing the sand-mixed liquid to deviate from the original flow path under the influence of inertial force, and finally guiding the sand to smoothly fall into the sand storage cavity.

[0059] In addition, some irregular protrusions can be arranged on the surface of the sand baffle to increase the turbulence degree of the sand-mixed liquid and help separate the sand in the sand-mixed liquid from the liquid flow. For example, the surface of the sand baffle can be set to be serrated, wavy, etc.

[0060] Further, in a possible implementation, the sand baffle can also be arranged in an inverted V-shaped structure. The V-shaped plate can guide the sand-mixed liquid to both sides of the central tube, so that the sand is deposited in the sand storage cavity outside the circulation flow path.

[0061] Further, in a possible implementation, the rotating blade can be arranged in a spiral structure. The spiral rotating blade can form a vortex flow field during rotation, generating a large shear force and turbulence, effectively improving the stirring effect. Moreover, the spiral blade can generate a greater stirring shear force under a given power consumption, so the energy consumption can be reduced while maintaining the same stirring effect. Compared with rotating blades of other shapes, the design of the spiral blade can improve the stirring efficiency and reduce the production cost.

[0062] Further, in a possible implementation, a first speed reducer assembly can be arranged between the first driving module and the sand pump to adjust the working intensity of the suction pump; a second speed reducer assembly can be arranged between the second driving module and the rotating blade to adjust the rotation speed of the rotating blade.

[0063] Further, in a possible implementation manner, the sand fishing tool may further include a downhole control mechanism and a ground control terminal. The ground control terminal is arranged on the ground and is used for sending control instructions to the downhole control mechanism; the downhole control mechanism is arranged downhole and is used for controlling the first driving module and the second driving module in response to the control instructions.

[0064] Further, in a possible implementation manner, the ground control terminal can be connected to the downhole control mechanism through a cable, and the downhole control mechanism can be connected to the housing through a cable, so as to complete the communication transmission of the control instructions.

[0065] Of course, the present invention is not limited thereto. The ground control terminal can also be connected to the downhole control mechanism in other ways to realize the control of the first driving module and the second driving module. For example, the communication and remote control between the ground control terminal and the downhole control mechanism can be realized through wireless connection methods such as Bluetooth, Wi-Fi communication, radio frequency signals, and infrared rays.

[0066] Further, in a possible implementation manner, a safety pin can be arranged at the connection port of the housing. For example, when the connection port of the housing is connected to the cable to realize the lowering and pulling out of the sand fishing tool, if the tool is stuck during the sand fishing process and the upward pulling force of the cable reaches a certain value, the safety pin arranged at the connection of the cable and the connection port of the housing will automatically disengage. At this time, the cable can be pulled out, and the sand fishing tool can be temporarily left in the well. Here, the shear force of the safety pin is greater than twice the normal working pulling force of the cable and less than the breaking force of the cable.

[0067] Further, in a possible implementation manner, a fishing structure is arranged at the upper end of the housing. After the sand fishing tool is temporarily left in the well due to being stuck, the sand fishing tool can be fished to the ground through contacting the fishing structure subsequently. For example, the fishing structure can be set in the shape of a fishhook, and the fishhook shape can have an upward bend or hook claw design, which is beneficial to grasping or hooking the object to be fished.

[0068] On the other hand, the present invention also provides a sand fishing method for the above-mentioned electric sand fishing tool, and the method includes the following steps:

[0069] Step S101: Lower the electric sand fishing tool into the well.

[0070] Step S102: When the electric sand fishing tool contacts the sand surface, start the sand pump and the rotating blade, stir the bottom sediment in the well with the rotating blade to form a sand-mixed liquid. The sand-mixed liquid enters the housing from the liquid inlet and flows upward under the suction of the sand pump. When the sand-mixed liquid reaches the baffle plate, the sand in the sand-mixed liquid is separated from the liquid flow, the sand settles downward into the sand storage cylinder for storage, and the liquid flow continues to flow upward to the sand pump and is discharged from the liquid outlet to the wellbore.

[0071] Step S103: After the sand fishing is completed, lift out the electric sand fishing tool and discharge the sand in the sand storage cylinder.

[0072] Further, in a possible implementation manner, in step S101, the sand fishing tool can be lowered into the well through a rope, or the sand fishing tool can be lowered into the well through a coiled tubing. For example, when conducting sand fishing work for a shallow well, a coiled tubing can be selected to repeatedly lift and lower the sand fishing tool; when conducting sand fishing work for a deep well, a cable or wire rope can be selected to repeatedly lift and lower the sand fishing tool. Further, in a possible implementation manner, when using a rope to lower the sand fishing tool into the well, during the process of lowering the sand fishing tool, it is possible to judge whether the sand fishing tool touches the sand surface based on the change in the tension of the rope.

[0073] Further, in a possible implementation manner, before lowering the sand fishing tool, the working time of the second drive module can be preset based on the well depth and the lowering speed of the sand fishing tool.

[0074] To better understand the above exemplary embodiments of the present invention, the following further illustrates them in combination with specific examples and drawings.

[0075] As Figure 1 shown, the electric sand fishing tool provided in this example for sand fishing operations mainly consists of seven major parts: a ground control terminal, a signal transmission cable (hereinafter referred to as a cable), a downhole control mechanism, a motor and reducer assembly A (hereinafter referred to as the first motor), a motor and reducer assembly B (hereinafter referred to as the second motor), a sand pumping pump, and a spiral rotating blade (hereinafter referred to as a spiral blade).

[0076] As Figure 2 shown, the downhole tool string provided in this example is connected in sequence from top to bottom (i.e., from the ground to the downhole) as follows: a ground control terminal, a signal transmission cable, a downhole control mechanism, a first motor, a sand pumping barrel, a second motor, and a spiral blade.

[0077] That is to say, the ground control terminal is set on the ground and is the core component of the entire device, used to send control instructions to the downhole control mechanism to realize the working functions of the sand pumping pump, the spiral blade, etc. The downhole control mechanism is connected to the ground control terminal through a signal transmission cable and is used to control the driving of the first motor and the second motor according to the control instructions sent by the ground control terminal to respectively realize the working of the sand pumping pump and the spiral blade. In addition, the ground control terminal has functions such as displaying voltage values, current values, stroke positions, etc., and has an overload protection function.

[0078] As Figure 3As shown in the figure, the housing 1 is a hollow pipe string with a hollow interior. The first motor 2 and the sand pumping pump 3 are arranged at the upper part of the housing 1, the second motor 6 and the spiral blade 7 are arranged at the lower part of the housing 1, and the sand baffle 4 and the sand storage cylinder 5 are arranged in the middle of the housing 1. The liquid inlet is arranged at the bottom of the housing 1, and the liquid outlet is arranged on the side of the housing 1.

[0079] The first motor 2 and the sand pumping pump 3 together form a conveying mechanism. The first motor 2 is located above the sand pumping pump 3. After being powered on, the first motor 2 can provide driving force for the sand pumping pump 3 to enable the operation of the sand pumping pump. A filter screen 11 is arranged at the lower part of the sand pumping pump 3 to prevent mud and sand from entering the impeller of the sand pumping pump 3, which may cause loss or failure of the impeller.

[0080] The sand baffle 4 and the sand storage cylinder 5 together form a sand storage mechanism. The sand baffle 4 is arc-shaped and is arranged directly above the sand storage cylinder 5. When the sand-mixed liquid reaches the sand baffle, the sand in the sand-mixed liquid will fall into the sand storage cylinder 5 for storage, while the liquid in the sand-mixed liquid will continue to flow upward to the sand pumping pump.

[0081] The sand storage cylinder accounts for the largest weight proportion in the entire tool string. During the sand fishing process, it provides gravity for the tool string by its own weight, so that the tool string always tightly presses on the sand surface and bears the reaction forces of the rotation of the motor and the rotation of the spiral blade. As Figure 4 shown, the sand storage cylinder 5 is composed of an outer cylinder 51, a centralizer 52 and a central pipe 53. Among them, both the outer cylinder 51 and the central pipe 53 are non-coupling pipe strings made of special materials. The upper and lower ends of the outer cylinder 51 have internal threads, and the central pipe 53 is fixed inside the outer cylinder 51 through the upper centralizer 52.

[0082] In addition, the outer cylinder can also be formed by connecting multiple non-coupling pipe strings through threads. The central pipe can be arranged in the outer cylinder in an inserted connection manner. When multiple non-coupling pipe strings are connected through threads to form the outer cylinder, the central pipes inside the outer cylinder are naturally connected together.

[0083] As Figure 5 shown, multiple centralizers can be arranged. The multiple centralizers are arranged in the circumferential space between the central pipe 53 and the outer cylinder 51 at certain intervals to fix the position of the central pipe.

[0084] A filter screen 11 can be arranged at the bottom of the outer cylinder 51 to filter out the excess liquid in the sand and leave the deposited sand in the sand storage cylinder. The structure of the filter screen is as Figure 6 shown.

[0085] The second motor 6 and the spiral blade 7 together form a stirring mechanism. The second motor 6 is located above the spiral blade 7. After being powered on, the second motor 6 can provide driving force for the spiral blade 7 to enable the operation of the spiral blade. As Figure 7As shown, the stirring mechanism is powered by the second motor output, the second motor 6 is arranged on the motor seat 9, and a stabilizer 10 is arranged between the motor seat 9 and the housing 1 to stabilize the position of the motor seat. In addition to the second motor, the motor seat also has a high-temperature lithium battery and a reducer assembly. The lower end of the second motor 6 is connected to a reducer, and the output shaft 8 of the reducer is connected to the spiral blade 7 by bolts. The motor power drives the spiral blade to rotate after being decelerated by the reducer, and the rotation speed can be adjusted.

[0086] In addition, the second motor is powered by a high-temperature lithium battery. The motor pre-working time can be set in advance before going down the well. After the designated attempt, the battery starts working within the predetermined time to provide power to the motor to realize the operation of the spiral blades.

[0087] The working principle of the above-mentioned sand bailing tool is as follows: the second motor rotates forward, and drives the spiral blades to work through the reducer. The spiral blades stir the sand at the bottom of the well under high-speed rotation to form a sand-mixing liquid, and transport the sand-mixing liquid to the circulation channel at the lower part of the shell; at the same time, the first motor rotates forward, and drives the sand pump to work through the reducer. Under high-speed rotation, a negative pressure is formed between the inner and outer circulation channels to achieve suction, and the sand-mixing liquid transported into the shell by the spiral blades is sucked upward, and then discharged from the shell through the upper discharge port after suction; the sand-mixing liquid flows upward through the suction action of the upper sand pump. When the sand-mixing liquid reaches the sand baffle, its channel becomes larger, the flow rate of the sand-mixing liquid slows down, and the sand settling speed is greater than the liquid flow return speed, thereby storing the sand in the sand storage cylinder.

[0088] like Figure 8 As shown, the operation process of the electric sand bailing tool specifically includes the following steps:

[0089] (1) Preset the working time of the second motor according to the well depth and the cable lowering speed, and test whether it can operate normally;

[0090] (2) Connect the cable to the downhole tool string reliably on the ground and test whether the cable signal transmission is normal;

[0091] (3) The tool string is lowered into the expected sand by the cable car, and the depth is calibrated by cable;

[0092] (4) Check the sand surface position. The cable car operator lifts the cable. If the sand surface depth is consistent with the sand surface provided by the design, the tool string is lifted to a position about 1m above the sand surface. If the sand surface depth is inconsistent with the design, the tool string is lifted to a certain height according to the surface rise data;

[0093] (5) Checking the preset working time of the second motor. When the preset time is reached, the second motor starts to work, driving the spiral blade to rotate;

[0094] (6) Ground operators send instructions via computer, and the control system drives the first motor to rotate forward, driving the sand pump to work at high speed. Due to the small inner flow passage, during the cyclic sand fishing process, the flow velocity of the fluid in the inner passage is relatively high, enabling better carrying of sand to flow upward;

[0095] (7) Slowly lower the cable, the tool string contacts the sand surface, and the entire tool string is pressed on the sand surface. The spiral blade rotates, stirring the bottom sediment and transporting it to the circulation passage inside the housing;

[0096] (8) The sand pump rotates at high speed, sucking up the sand - mixed liquid transported into the circulation passage by the spiral blade. When the sand - mixed liquid reaches the upper baffle plate, the passage becomes larger, the flow velocity becomes smaller, the sedimentation speed of the sand is greater than the upward flow velocity of the fluid, and the sand falls into the sand storage cylinder. The liquid enters the impeller of the sand pump through the sand - filtering net and is discharged to the wellbore from the discharge port;

[0097] (9) The cable operator observes the tension of the cable to judge whether the tool string is tightly pressed on the sand surface. If the tension increases, intermittently lower the cable to keep the tool string always pressed on the sand surface until sand fishing reaches the expected depth. If the tension decreases during the lowering process, stop lowering, observe the change of the tension, judge the down - hole situation, and choose to continue sand fishing or stop sand fishing;

[0098] (10) If there is a large amount of sediment in the well, calculate the number of sand storage pipes according to the sediment volume, but the maximum weight of the entire tool string (including formation sand) does not exceed the lifting force of the cable during normal operation; repeat steps (3) - (5) to continue sand fishing downward until sand fishing reaches the designed depth.

[0099] Before the tool string is lowered into the well, it is debugged on the ground. If there are electronic or mechanical problems, they are solved in a timely manner. Affected by well water, oil, sediment, high - temperature environment, etc., various problems will occur during actual use.

[0100] When the entire system malfunctions, the tool can be lifted out and inspected or replaced with a new set of equipment on the ground.

[0101] During sand fishing, if the tool gets stuck, a safety pin is designed at the connection between the cable and the tool. When the upward pulling force of the cable reaches a certain value, the safety pin disengages, and the cable can be lifted out while the tool remains in the well. The shear force of the safety pin is greater than twice the normal working pulling force of the cable and less than the cable breaking force. A fishing structure is left at the top of the tool to provide a solution for subsequent accident handling.

[0102] The preferred embodiments of the present invention have been described in detail above with reference to the accompanying drawings. However, the present invention is not limited to the specific details in the above - mentioned embodiments. Within the scope of the technical concept of the present invention, various simple modifications can be made to the technical solutions of the present invention, and these simple modifications all fall within the protection scope of the present invention.

[0103] In addition, it should be noted that, among the various specific technical features described in the above specific embodiments, without contradiction, they can be combined in any appropriate manner. To avoid unnecessary repetition, the present invention will not separately describe various possible combination methods.

[0104] In addition, any combinations can also be made among various different embodiments of the present invention, as long as they do not violate the idea of the present invention, and they should also be regarded as the content disclosed by the present invention.

Claims

1. An electric sand fishing tool, characterized in that, The sand fishing tool includes: a housing, a conveying mechanism, a stirring mechanism, and a sand storage mechanism; The housing is a hollow cylinder. Inside the housing, there are a first cavity, a second cavity, and a third cavity connected in sequence from the ground to the wellbore direction. A liquid inlet is provided at the bottom of the third cavity, and a liquid outlet is provided at the top or side of the first cavity; The conveying mechanism is located in the first cavity, the sand storage mechanism is located in the second cavity, and the stirring mechanism is located in the third cavity; The conveying mechanism includes a first driving module and a sand pump. The first driving module is connected to the sand pump and is used to provide driving force to the sand pump. The sand pump is used to convey the sand - mixed liquid from the liquid inlet of the third cavity to the liquid outlet of the first cavity; The sand storage mechanism includes a sand storage cylinder and a baffle plate. The sand storage cylinder includes: an outer cylinder and a central tube. The central tube is arranged inside the outer cylinder. A sand storage cavity capable of storing sand is formed between the central tube and the outer cylinder. A circulation channel for the upward flow of the sand - mixed liquid is formed inside the central tube. The baffle plate is arranged directly above the circulation channel and is used to change the flow rate and flow direction of the sand - mixed liquid; The stirring mechanism includes a second driving module and a rotating blade. The second driving module is connected to the rotating blade and is used to provide driving force to the rotating blade. The rotating blade is used to stir the sand - mixed liquid in the wellbore; 2. The electric sand fishing tool according to claim 1, wherein, A filter screen is arranged between the sand pump and the baffle plate; 3. The electric sand fishing tool according to claim 1, characterized in that A filter screen is arranged at the bottom of the outer cylinder; 4. The electric sand fishing tool according to claim 1, characterized in that, A plurality of centralizing blocks are arranged between the outer cylinder and the central tube; 5. The electric sand fishing tool according to claim 1, characterized in that The sand storage cylinder is made of an alloy material; 6. The electric sand fishing tool according to claim 5, characterized in that, The alloy material is aluminum alloy; 7. The electric sand fishing tool according to claim 1, characterized in that, The baffle plate is of an arc - shaped structure; 8. The electric sand fishing tool according to claim 1, characterized in that, The baffle plate is of an inverted V - shaped structure; 9. The electric sand fishing tool according to claim 1, wherein The rotating blade is of a spiral structure; 10. The electric sand fishing tool according to claim 1, wherein, A first speed reducer assembly is arranged between the first driving module and the sand pump; 11. The electric sand fishing tool according to claim 1, characterized in that, A second speed reducer assembly is arranged between the second driving module and the rotating blade; 12. The electric sand fishing tool according to claim 1, characterized in that, The sand fishing tool further includes: a downhole control mechanism and a ground control terminal; The ground control terminal is used to send control instructions to the downhole control mechanism, and the downhole control mechanism is used to control the first driving module and the second driving module in response to the control instructions; 13. The electric sand fishing tool according to claim 12, characterized in that, The ground control terminal is connected to the downhole control mechanism through a cable, and the downhole control mechanism is connected to the housing through a cable; 14. The electric sand fishing tool according to claim 13, characterized in that, A safety pin is arranged at the connection between the housing and the cable; 15. The electric sand fishing tool according to claim 1, characterized in that, A fishing structure is arranged at the upper end of the housing; 16. A sand fishing method for an electric sand fishing tool, characterized in that, The sand fishing method is realized by the electric sand fishing tool according to any one of claims 1 - 15 and includes: Lowering the sand fishing tool into the well; When the sand fishing tool touches the sand surface, start the sand pump and the rotating blade. Use the rotating blade to stir the bottom - deposited sand to form a sand - mixed liquid. The sand - mixed liquid enters the housing from the liquid inlet and flows upward under the suction of the sand pump. When the sand - mixed liquid reaches the baffle plate, the sand in the sand - mixed liquid is separated from the liquid flow. The sand sinks downward and is stored in the sand storage cylinder, and the liquid flow continues to flow upward to the sand pump and is discharged from the liquid outlet to the wellbore; After the fishing is completed, lift out the sand fishing tool and discharge the sand in the sand storage cylinder; 17. The sand fishing method of the electric sand fishing tool according to claim 16, characterized in that, Lower the sand fishing tool into the well through a rope, and the rope is a cable or a steel wire rope; 18. The sand fishing method of the electric sand fishing tool according to claim 17, characterized in that, Lower the sand fishing tool into the well through a coiled tubing; 19. The sand fishing method of the electric sand fishing tool according to claim 17, characterized in that, The sand fishing method further includes: During the process of lowering the sand fishing tool, it is judged whether the sand fishing tool touches the sand surface based on the change of the rope tension.

20. The sand fishing method of the electric sand fishing tool according to claim 16, characterized in that, The sand fishing method further includes: before lowering the sand fishing tool, presetting the working time of the second driving module based on the well depth and the lowering speed of the sand fishing tool.

Images