CN112443291A - Vortex generator - Google Patents

Abstract

The invention discloses a swirl generator which mainly comprises a central shaft, a one-way valve, an outer shell, a rotor, a stator and a flow guide body; wherein: the periphery of the central shaft is provided with an annular groove, the upper part of the central shaft is provided with a bypass hole, and the lower part of the central shaft is provided with a drainage hole; the outer shell is wrapped on the annular groove of the central shaft and forms rotary fit with the central shaft, an annular driving cavity is formed between the outer shell and the central shaft, and the upper part and the lower part of the annular driving cavity are respectively communicated with the bypass hole and the drainage hole; the one-way valve is arranged in the bypass hole; the rotor and the stator are arranged between the outer shell and the central shaft to form an annular driving cavity, the rotor is fixed on the inner wall of the outer shell, and the stator is fixed on the outer wall of the central shaft; the flow guide body is arranged on the outer surface of the outer shell. The swirl generator can completely meet the well cementation process requirements of domestic straight wells, directional wells and horizontal wells with complex structures, and is a novel tool which is simple in structure, convenient to operate, low in cost, safe and reliable.

Description

Vortex generator

Technical Field

The invention relates to an underground tool in the fields of petroleum and natural gas drilling, coal bed gas drilling, geological exploration, mine drilling and the like, in particular to a vortex generator.

Background

After the well drilling and completion operation is completed, in order to ensure the stability of the well and the safety and smoothness of subsequent construction operation, a casing is put into the well, cement is injected into an annular space between the casing and a well wall, and a stable shaft is formed after the cement is solidified. In the well cementation process, after the casing is put into a borehole, cement slurry is injected from a casing opening, and returns from the bottom of the casing to enter an annulus between the casing and a borehole wall, along with continuous injection of the cement slurry, the drilling fluid in the annulus is replaced by the cement slurry out of the borehole by a one-dimensional axial flow, and the conventional mode has the following defects: (1) the flow rate of the annular near-well wall area is low, the drilling fluid has high adhesion, high flow rate displacement is required for high adhesion, high energy consumption is required for high flow rate displacement, and high energy consumption is limited by the pump pressure and the stratum pressure bearing capacity; (2) the well bore is irregular, the well wall is jagged and uneven, and the conventional one-dimensional axial flow is easy to cause the backflow of the drilling fluid, so that the drilling fluid is retained; (3) the lower casing string often has insufficient displacement, making clean-up difficult.

Aiming at the problems, a great deal of research work is carried out at home and abroad, a plurality of displacement methods are provided, corresponding tools are developed, and the main purpose is to overcome the defect of one-dimensional axial flow in displacement. The spiral flow displacement method is characterized in that the effect of circumferential shear carrying is exerted on the basis of one-dimensional axial flow displacement, and the displacement of the drilling fluid in the borehole annulus is facilitated. Conventional methods of generating helical flow:

firstly, inject into rotatory casing string in the time of grout, but need higher rotatory moment of torsion, the site operation degree of difficulty is big, and the risk is high. For example: chinese patent publication No. CN2406060Y discloses a liquid vortex generator. The swirl generator consists of a body, swirl guide belts, guide grooves and fixing bolts, wherein 4 guide grooves are uniformly welded on the body along the circumference, each guide groove is embedded with the swirl guide belt, and the fixing bolts are respectively screwed in 3 screw holes at the upper end and the lower end of the body. When the device is used, the upper fixing bolt and the lower fixing bolt of the device body are loosened and then sleeved outside the sleeve body, then the bolts are screwed down, the bolts can be screwed down along with the sleeve pipe column to the lower end of the part with the larger hole diameter, the rotational flow sheet is contacted with the well wall, a rotational flow channel is formed, when liquid passes through, the liquid can form rotational flow to fully drive the liquid in the well hole, a rotational flow effect is formed, and the purpose of improving the displacement efficiency is achieved. In order to ensure that the swirl generator is in a central position in the borehole, the upper and lower parts of the swirl generator can be respectively provided with a centralizer. The swirl generator has two specifications of phi 177.8 and 139.7, and the length of swirl which can be formed during operation is generally 20-40 m. During well cementation, 1-6 cyclone generators with corresponding specifications can be selected according to the well diameter and the length of a large-well-diameter well section in a well.

And secondly, the rotational flow centralizer is used, so that the rotational flow centralizer is convenient to use and low in risk, but rotational flow energy is low, the length of a borehole capable of generating a rotational flow effect is short, and the capacity of replacing drilling fluid is limited. For example: the mud cake scraping type spiral-flow type righting tool of the cement paste spiral-flow generator disclosed in Chinese patent publication No. CN109138861A comprises a rubber spiral wing seat and a rigid spiral wing which are fixed on the outer wall of an outer sleeve, wherein the rubber spiral wing is fixed on the rubber spiral wing seat. The number of the rubber spiral wing seats and the number of the rigid spiral wings are 4, and the rubber spiral wing seats and the rigid spiral wings are fixed on the outer sleeve at intervals. The rubber spiral wing seat comprises a left base and a right base, the sections of the left base and the right base are L-shaped, and the left base and the right base are symmetrically welded on the outer sleeve to form a slideway; the cross section of the rubber spiral wing is T-shaped, and the bottom edge of the rubber spiral wing is arranged in the slideway and fixed by a screw.

Therefore, it is urgently needed to develop a swirl generator which not only meets the requirements of the conventional well cementation process, but also can generate a helical flow with larger energy so as to fully exert the technical advantages of the helical flow for replacing the drilling fluid, and meanwhile, the swirl generator also has the characteristics of safety, reliability, simple structure and convenience in maintenance.

Disclosure of Invention

The invention aims to give full play to the technical advantages of spiral flow replacing drilling fluid and provide a spiral flow generator which further improves the well cementation quality, generates larger energy spiral flow and gives full play to the function of spiral flow replacing drilling fluid under the condition of not changing the existing well cementation process and equipment.

The technical scheme adopted by the invention for solving the technical problems is as follows:

a swirl generator mainly comprises a central shaft, a one-way valve, an outer shell, a rotor, a stator and a flow guide body; wherein: the periphery of the central shaft is provided with an annular groove, the upper part of the central shaft is provided with a bypass hole, and the lower part of the central shaft is provided with a drainage hole; the outer shell is wrapped on the annular groove of the central shaft and forms rotary fit with the central shaft, an annular driving cavity is formed between the outer shell and the central shaft, and the upper part and the lower part of the annular driving cavity are respectively communicated with the bypass hole and the drainage hole; the one-way valve is arranged in the bypass hole; the rotor and the stator are arranged between the outer shell and the central shaft to form an annular driving cavity, the rotor is fixed on the inner wall of the outer shell, and the stator is fixed on the outer wall of the central shaft; the flow guide body is arranged on the outer surface of the outer shell.

The above scheme further comprises:

and a bearing A is arranged at the joint of the upper part of the outer shell and the central shaft, and a bearing B is arranged at the joint of the lower part of the outer shell and the central shaft.

The bearing A is arranged at the radial joint of the outer shell and the central shaft, and the bearing B is arranged at the axial joint of the outer shell and the central shaft.

The bearing A is a rolling bearing, and the bearing B is a thrust bearing.

The upper section of the central shaft annular groove is a conical inclined plane, and the bypass hole is formed in the conical inclined plane section.

The bottom of the central shaft annular groove is a plane, and the discharge hole is axially arranged along the annular driving cavity between the outer shell and the central shaft.

The bypass holes are multiple and evenly distributed.

The drainage holes are multiple and are uniformly distributed; or the vent hole is of an integral annular structure.

The flow guide body is of a spiral wing structure.

The number of the spiral wings is 2-6, and the spiral wings are evenly distributed on the outer shell.

The working principle of the vortex generator of the invention is as follows:

the vortex generator is arranged at the lowest end of the casing string and is arranged in a well along with the casing string, in the well cementing process, well cementing liquid enters a driving cavity between the outer shell and the central shaft after passing through a bypass hole and a one-way valve of the central shaft, the rotor is arranged on the inner wall of the outer shell, the stator is arranged on the outer wall of the central shaft, the rotor starts to rotate under the action of high-pressure well cementing liquid and drives the outer shell to rotate at a high speed, the well cementing liquid enters an annular space after passing through the drainage hole and returns upwards, and the flow guide body is processed on the outer wall due to the high-speed rotation of the outer shell.

The rotational flow generator has high rotational speed, namely the initial speed of the generated helical flow is high, and the energy is high, so that compared with the conventional helical flow method, the method can extend upwards for a longer distance, therefore, the efficiency of displacing the original drilling fluid in the annulus is higher, and the well cementation quality is better. The swirl generator converts the hydraulic energy of the cementing liquid injected into the casing string into mechanical energy of high-speed rotation of the outer shell, and then drives the annular cementing liquid to generate high-speed upward spiral flow, namely, the mechanical energy is converted into hydraulic kinetic energy.

The on-site test shows that the swirl generator can completely meet the technical requirements of the well cementation construction, and the application data analysis shows that the excellent rate of the well cementation quality is improved by 95.6-166% on average compared with the conventional well cementation method, and particularly, the swirl generator greatly improves the well cementation quality in the well cementation process of deep wells, ultra-deep wells, slim holes and wells with complex structures and meets the design requirements.

Compared with the prior art, the invention has the beneficial effects that: the rotational speed of the rotational flow generator is high, namely the initial speed for generating the spiral flow is high, the energy is high, the upward extension distance of the spiral flow is longer, and the annular displacement efficiency is higher; the hydraulic energy of the cementing fluid injected into the casing string is converted into mechanical energy of high-speed rotation of the outer shell, and then the annular cementing fluid is driven to generate high-speed upward spiral flow, so that the energy loss is reduced to the maximum extent, and the mechanical efficiency of the spiral generator is improved; the device also has the characteristics of simple structural design, reliable performance, convenient operation and low cost, and is convenient for large-scale popularization and use.

Drawings

Fig. 1 is a schematic view of a half-section structure of a swirl generator of the present invention.

Fig. 2 is a cross-sectional view of fig. 1 taken along section a-a.

In the figure, 1-central shaft, 2-bearing A, 3-bypass hole, 4-one-way valve, 5-outer shell, 6-rotor, 7-stator, 8-flow guide body, 9-bearing B and 10-drain hole.

Detailed Description

The present invention is described in detail below with reference to the attached drawings.

Example 1

A swirl generator comprises a central shaft 1, a one-way valve 4, an outer shell 5, a rotor 6, a stator 7 and a flow guide body 8; wherein: the periphery of the central shaft 1 is provided with an annular groove, the upper part of the central shaft is provided with a bypass hole 3, and the lower part of the central shaft 1 is provided with a drainage hole 10. The outer shell 5 wraps the annular groove of the central shaft 1 and is in rotating fit with the central shaft 1, an annular driving cavity is formed between the outer shell 5 and the central shaft 1, and the annular driving cavity is communicated with the bypass hole 3 and the drainage hole 10 from top to bottom respectively. Here, referring to fig. 1, the part of the central shaft 1 with the annular groove is of a closed structure, which ensures that the fluid can only flow along the bypass hole 3, the annular driving cavity to the drain hole 10. The check valve 4 is arranged in the bypass hole to prevent the fluid from flowing reversely. The rotor 6 and the stator 7 are arranged between the outer shell 5 and the central shaft 1 to form an annular driving cavity, the rotor 6 is fixed on the inner wall of the outer shell 5, the stator 7 is fixed on the outer wall of the central shaft 1, and the stator and the rotor form high-speed rotation fit under the driving of a fluid. The flow guide body 8 is arranged on the outer surface of the outer shell 5, and the outer shell and the flow guide body are driven to synchronously rotate through the rotation of the rotor, so that fluid outside the sleeve generates upward rotation energy.

Example 2

Based on embodiment 1, further comprising:

a bearing A2 is mounted on the joint of the upper part of the outer shell 5 and the central shaft 1, and a bearing B9 is mounted on the joint of the lower part of the outer shell 5 and the central shaft 1.

The bearing a2 is mounted on the radial joint of the outer housing 5 and the central shaft 1, and the bearing B9 is mounted on the axial joint of the outer housing 5 and the central shaft 1.

The bearing A is a rolling bearing, and the bearing B is a thrust bearing.

Example 3

Based on embodiment 1 or 2, further comprising:

the upper section of the annular groove outside the central shaft 1 is a conical inclined plane or an arc-shaped surface, and the bypass hole 3 is arranged on the conical inclined plane or the arc-shaped surface. This design better addresses the forces of the fluid on the rotor.

The bottom of the annular groove outside the central shaft 1 is a plane, and the drain hole 10 is axially arranged along the annular driving cavity between the outer shell 5 and the central shaft 1 so as to increase the smoothness of the flow channel.

The number of the bypass holes 3 is multiple, and the bypass holes are specifically determined according to factors such as the aperture size, the fluid flow, the pipe diameter of the sleeve, the pressure and the like and are uniformly distributed.

A plurality of drain holes 10 are arranged, the number and the aperture size of the drain holes are specifically set according to the requirement and are uniformly distributed; or vent hole 10 may be directly formed as a unitary annular ring.

The flow guide body 8 is of a spiral wing structure, and the spiral wing structure in a comparison document can be used for reference. The number of which is 2-6, preferably 2, and which is evenly distributed over the outer shell.

Exemplary embodiment 4

Referring to fig. 1 and 2, the swirl generator mainly comprises a central shaft 1, a bearing 2, a bypass hole 3, a one-way valve 4, an outer shell 5, a rotor 6, a stator 7, a flow guide body 8 and a discharge hole 10. The upper portion of center pin 1 processes by-pass hole 3, installation check valve 4 in by-pass hole 3, and rotor 6 installs on 5 inner walls of shell body, and stator 7 installs on 1 outer wall of center pin, installs bearing 2 between 5 upper portions of shell body and the center pin 1, and 5 outer walls of shell body process baffle 8, 1 lower part processing discharge orifice 10 of center pin, installation bearing 9 between 5 lower parts of shell body and the 1 lower part of center pin.

Further, in order to increase the sealing property between the outer housing 5 and the center shaft 1, a seal is added to a joint portion thereof, or a seal bearing is used.

The swirl generator is arranged at the lowest end of the casing string and is arranged in a well along with the casing string, and in the well cementation process, well cementation liquid enters a cavity between the outer shell 5 and the central shaft 1 after passing through the bypass hole 3 and the one-way valve 4 of the central shaft 1. The vortex generator is internally provided with a screw or turbine driving structure, the rotor 6 is arranged on the inner wall of the outer shell 5, the stator 7 is arranged on the outer wall of the central shaft 1, the rotor 6 starts to rotate under the action of high-pressure cementing liquid and drives the outer shell 5 to rotate at a high speed, and the cementing liquid enters the annular space after passing through the drainage hole 10 and returns upwards. Because the outer shell 5 rotates at a high speed and the flow guide body 8 is processed on the outer wall, the well cementation liquid returns upwards in the annular space, and simultaneously, spiral flow is generated under the action of the driving force of the high-speed rotation of the outer shell 5, and the well cementation liquid in the annular space returns upwards in the spiral flow state along with the continuous injection of the well cementation liquid.

The rotational flow generator has high rotational speed, namely the initial speed of the generated helical flow is high, and the energy is high, so that compared with the conventional helical flow method, the method can extend upwards for a longer distance, therefore, the efficiency of displacing the original drilling fluid in the annulus is higher, and the well cementation quality is better. The swirl generator converts the hydraulic energy of the cementing liquid injected into the casing string into mechanical energy of high-speed rotation of the outer shell, and then drives the annular cementing liquid to generate high-speed upward spiral flow, namely, the mechanical energy is converted into hydraulic kinetic energy.

Claims (10)

1. The vortex generator mainly comprises a central shaft (1), a one-way valve (4), an outer shell (5), a rotor (6), a stator (7) and a flow guide body (8); the method is characterized in that: the periphery of the central shaft (1) is provided with an annular groove, the upper part of the central shaft is provided with a bypass hole (3), and the lower part of the central shaft (1) is provided with a drainage hole (10); the outer shell (5) is wrapped on the annular groove of the central shaft (1) and forms a rotary fit with the central shaft (1), an annular driving cavity is formed between the outer shell (5) and the central shaft (1), and the upper part and the lower part of the annular driving cavity are respectively communicated with the bypass hole (3) and the drainage hole (10); the check valve (4) is arranged in the bypass hole (3); the rotor (6) and the stator (7) are arranged between the outer shell (5) and the central shaft (1) to form an annular driving cavity, the rotor (6) is fixed on the inner wall of the outer shell (5), and the stator (7) is fixed on the outer wall of the central shaft (1); the flow guide body (8) is arranged on the outer surface of the outer shell (5).

2. The vortex generator of claim 1 wherein: and a bearing A (2) is arranged at the joint of the upper part of the outer shell (5) and the central shaft (1), and a bearing B (9) is arranged at the joint of the lower part of the outer shell (5) and the central shaft (1).

3. The vortex generator of claim 2 wherein: the bearing A (2) is arranged at the radial joint of the outer shell (5) and the central shaft (1), and the bearing B (9) is arranged at the axial joint of the outer shell (5) and the central shaft (1).

4. The vortex generator of claim 3 wherein: the bearing A (2) is a rolling bearing, and the bearing B (9) is a thrust bearing.

5. The vortex generator of any one of claims 1 to 4 wherein: the upper section of the annular groove of the central shaft (1) is a conical inclined plane, and the bypass hole (3) is arranged on the conical inclined plane section.

6. The vortex generator of any one of claims 1 to 4 wherein: the bottom of the annular groove of the central shaft (1) is a plane, and the drainage hole (10) is axially arranged along an annular driving cavity between the outer shell (5) and the central shaft (1).

7. The vortex generator of claim 5 wherein: the bypass holes (3) are distributed uniformly.

8. The vortex generator of claim 6 wherein: the drainage holes (10) are distributed uniformly; or the drain hole (10) is of an integral annular structure.

9. The vortex generator of any one of claims 1 to 4 wherein: the flow guide body (8) is of a spiral wing structure.

10. The vortex generator of claim 9 wherein: the number of the spiral wings is 2-6, and the spiral wings are evenly distributed on the outer shell (5).

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