Cleaning device for lens of differential pressure type underground video imaging instrument

Abstract

The invention belongs to the technical field of oil and gas well observation, and relates to a differential pressure type underground video imaging instrument lens cleaning device which comprises an underground video imaging instrument and a differential pressure type structure body. The differential pressure type structure body is arranged outside the cylindrical side wall of the underground video imaging instrument in a sleeving mode. A nozzle is arranged at one end of the inner cavity, which is positioned at the lens of the underground video imaging instrument, a liquid collecting port is arranged at one end of the inner cavity, which is far away from the lens of the underground video imaging instrument, and the effective liquid flow area of the liquid collecting port is larger than that of the nozzle. When the underground video imaging instrument is rapidly lifted up, well fluid can be sprayed out to clean a lens; according to the method, the operation period is shortened, the operation efficiency is improved, and compared with the mode of underground liquid collection and lifting flushing, the method is easy to operate, the lens can be continuously flushed, and the situation that the original shaft well liquid environment is disturbed and well liquid is turbid due to repeated lifting and descending is avoided.

Description

Technical Field

[0001] The invention belongs to the technical field of oil and gas well observation, and in particular relates to a pressure difference type downhole video imaging instrument lens cleaning device. Background Art

[0002] During the downhole operation of oil and gas wells, the wellbore may be deformed, damaged, blocked and other abnormal conditions, resulting in the downhole operation not being able to proceed normally. Therefore, it is necessary to clarify the specific problems of the wellbore, and then take corresponding measures to deal with the wellbore problems and restore the wellbore to normal. The downhole video imaging instrument of the oil and gas well works based on the principle of visible light imaging. Its front end is equipped with a camera to obtain the wellbore image, which can intuitively and clearly understand the wellbore problem and provide an objective and true basis for the next step of operation measures. However, the downhole environment of oil and gas wells is complex, and there may be oil stains, impurities and other substances in the well fluid that are not conducive to imaging detection, affecting the imaging effect. If the camera lens is blocked by impurities, oil stains or other foreign matter, the video image of the wellbore cannot be obtained. The solution of the prior art is to lift the detection instrument out of the oil and gas wellbore after the lens is contaminated, and then lower it again for detection after cleaning the lens on the ground. Utility model CN202322888470 mentions a method of lowering the collected liquid into the cavity by a piston, and lifting the piston to push the liquid to flush the lens.

[0003] However, after the camera lens is contaminated, the detection instrument is lifted out of the oil and gas wellbore, and the lens is cleaned on the ground before being lowered for detection. The lens may be contaminated again when it is lowered again, which makes the operation cycle uncontrollable, reduces the operation efficiency, and increases the operation cost. The utility model CN202322888470 uses a piston to lower the collected liquid into the cavity, and lifts the piston to push the liquid to flush the lens. Each time it is lowered, only the liquid in the cavity volume can be collected, and then it is lowered for flushing. If it is not rinsed clean, it is necessary to lift up the collected well fluid and lower the lens for flushing many times. The instrument is repeatedly lifted and lowered, and the flushing efficiency is not high. In the process of lifting and lowering the instrument, the impurities in the wellbore will change from a static state to a suspended state, causing the wellbore environment to become turbid, which is not conducive to imaging observation.

[0004] Therefore, a lens cleaning device or cleaning method is needed to solve the above technical problems by achieving continuous and multiple flushing of the lens, ensuring that the lens is clean, minimizing interference with the well fluid environment, shortening the operation cycle, and having a simple operation process. Summary of the invention

[0005] In order to solve the above technical problems, the present invention provides the following technical solutions: a pressure differential downhole video imaging instrument lens cleaning device, comprising: a downhole video imaging instrument, a pressure differential structure body; the downhole video imaging instrument is cylindrical, and a downhole video imaging instrument lens is arranged on the cylindrical front end surface of the downhole video imaging instrument; the pressure differential structure body is cylindrical, and the pressure differential structure body is coaxially sleeved outside the cylindrical side wall of the downhole video imaging instrument; a ring-shaped inner cavity is arranged in the pressure differential structure body, and the inner cavity is coaxial with the pressure differential structure body;

[0006] The main body of the pressure differential structure is located at the tube mouth on one side of the lens of the downhole video imaging instrument, and does not block the lens of the downhole video imaging instrument. The main body of the pressure differential structure can be detachably connected to the downhole video imaging instrument; the inner cavity is located at one end of the lens of the downhole video imaging instrument and is provided with a nozzle, the nozzle is connected to the inside and outside of the inner cavity, and the spray direction of the nozzle is toward the lens of the downhole video imaging instrument; the inner cavity is provided with a liquid collecting port at one end away from the lens of the downhole video imaging instrument, the liquid collecting port is connected to the inside and outside of the inner cavity, and the opening direction of the liquid collecting port is upward along the axial direction of the downhole video imaging instrument;

[0007] The effective liquid flow area of ​​the liquid collecting port is more than five times greater than the effective liquid flow area of ​​the nozzle; when the downhole video imaging instrument lens needs to be cleaned, the downhole video imaging instrument is quickly lifted up, and since the effective liquid flow area of ​​the liquid collecting port is more than five times greater than the effective liquid flow area of ​​the nozzle, a pressure difference is generated, so that the well fluid in the inner cavity is ejected from the inner cavity through the nozzle, and at the same time, the external well fluid flows into the inner cavity from the liquid collecting port, so that the well fluid at the nozzle can continuously clean the downhole video imaging instrument lens.

[0008] Preferably, the inner cavity is shaped like a cone that is larger at the top and smaller at the bottom, with the nozzle located at the small end of the cone and the liquid collection port located at the large end of the cone. The cone-shaped inner cavity that is larger at the top and smaller at the bottom can generate a greater pressure difference when the downhole video imaging instrument is quickly lifted, thereby enhancing the cleaning effect.

[0009] More preferably, the nozzle is in a circular shape, and the nozzle, the inner cavity, and the pressure difference type structure body have the same rotation axis; because the nozzle is in a circular shape and the spray direction of the nozzle is toward the downhole video imaging instrument lens, when the external well fluid flows into the inner cavity from the liquid collecting port and then sprays out from the nozzle from the inner cavity, the well fluid sprayed in a circular shape directly washes the downhole video imaging instrument lens, so that the well fluid at the nozzle can continuously clean the downhole video imaging instrument lens.

[0010] Preferably, there are a plurality of nozzles, which are coaxially and evenly distributed in a circular shape around the lens of the downhole video imaging instrument; the uniformly distributed nozzles in a circular shape can make the well fluid cleaning area more uniform and eliminate cleaning dead corners.

[0011] More preferably, the lower end face of the pressure differential structure body is in the shape of an annular step, and the nozzle is located on the inner wall of the annular step on the lower end face of the pressure differential structure body; the nozzle is arranged on the stepped inner wall of the annular step, so that the nozzle of the downhole video imaging instrument lens will not directly contact the well wall when it is lowered, thereby preventing the nozzle from being damaged or blocked.

[0012] More preferably, the lower end face of the pressure differential structure body is flush with the shooting end of the downhole video imaging instrument lens, the nozzle is in the shape of a curved tube protruding from the lower end face of the pressure differential structure body, and the injection channel in the nozzle bends outward from the inner cavity toward the downhole video imaging instrument lens; the nozzle protrudes axially from the shooting end face of the downhole video imaging instrument lens, so the nozzle can provide certain protection for the downhole video imaging instrument lens to prevent the end face of the downhole video imaging instrument lens from directly colliding with large particles of debris or the well wall underground, and the internal injection pipe of the nozzle is bent and rotated back to the end face of the downhole video imaging instrument lens, and the bent pipeline reduces the head loss of the cleaning well fluid and avoids the loss of water pressure caused by bending.

[0013] More preferably, the liquid collecting port is annular and is located at the upper end surface of the pressure differential structure body, and the liquid collecting port is arranged around the downhole video imaging instrument; the annularly evenly distributed liquid collecting ports at the upper end surface can collect well fluid more effectively and prevent the pressure difference from being reduced due to insufficient well fluid or uneven influx.

[0014] Preferably, a straightening spring is provided at the upper end of the pressure differential structure body. The straightening spring is a strip-shaped elastic deformation piece. The middle part of the straightening spring bulges radially outward. The lower end of the straightening spring is detachably connected to the upper part of the pressure differential structure body. The upper end of the straightening spring is slidably connected to the outer circumference of the downhole video imaging instrument.

[0015] More preferably, the righting spring pieces are provided with three to six pieces, the upper ends of the righting spring pieces are fixedly connected to the outer circumference of the fixing ring on the spring pieces, the inner ring of the fixing ring on the spring pieces is slidably sleeved on the outer circumference of the downhole video imaging instrument, and the three to six righting spring pieces are evenly distributed around the outer circumference of the downhole video imaging instrument.

[0016] Preferably, a filter screen is provided at the liquid collecting port; the filter screen is used to filter sand or debris in the well fluid to prevent clogging of the nozzle.

[0017] The beneficial effects of the present invention are:

[0018] 1. When the lens is contaminated during the underground operation, the present invention shortens the operation cycle and improves the operation efficiency compared to lifting the instrument to the ground for cleaning. Compared with the method of collecting liquid underground and lifting it up for flushing, the present invention is simple to operate and can continuously flush the lens, avoiding repeated lifting and lowering to disturb the original wellbore well fluid environment and make the well fluid turbid.

[0019] 2. The device of the present invention is independent of the downhole video imaging detection instrument, and is easy to carry and transport. A suitable differential pressure flushing device can be installed according to different instrument calibers, and it has high adaptability. At the same time, different water outlet designs can be selected according to needs, thereby reducing the cost of reproducing the instrument.

[0020] 3. The present invention is green and environmentally friendly in the entire cleaning process, reducing pollution to the underground well and the surrounding environment. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 It is a structural diagram of a pressure difference type downhole video imaging instrument lens cleaning device of the present invention;

[0022] Figure 2 is a stereogram of the present invention;

[0023] Figure 3 It is a front view of the present invention.

[0024] In the figure, 1. downhole video imaging instrument; 2. downhole video imaging instrument lens; 3. fixing ring on spring piece; 4. righting spring piece; 5. limiting ring; 6. fixing structure under spring piece; 7. differential pressure structure body; 8. limiting sleeve; 9. water outlet structure; 10. fixing screw on the upper end of righting spring piece; 11. fixing screw on limiting ring; 12. screw on the lower section of righting spring piece; 13. fixing screw on the main body; 14. inner cavity; 15. nozzle; 16. liquid collecting port. DETAILED DESCRIPTION

[0025] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the relevant technologies in the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0026] like Figures 1 to 3 As shown, a pressure difference downhole video imaging instrument lens cleaning device of this embodiment can realize downhole video imaging instrument lens cleaning, and the operation is simple and has continuous and multiple cleaning capabilities.

[0027] The pressure differential downhole video imaging instrument lens cleaning device of this embodiment is installed at the front end of the downhole video imaging instrument 1, and consists of an upper fixing ring 3 of the spring piece, a straightening spring piece 4, a limiting ring 5, a fixing structure 6 under the spring piece, a pressure differential structure main body 7, a limiting sleeve 8, a water outlet structure 9, a fixing screw 10 on the upper end of the straightening spring piece, a limiting ring fixing screw 11, a screw 12 on the lower section of the straightening spring piece, and a main body fixing screw 13.

[0028] The limit ring 5 is fixed to the outer wall of the downhole video imaging instrument 1 through four sets of limit ring fixing screws 11, and the limit ring fixing screws 11 are tightened into the fixing holes on the outer wall of the downhole video imaging instrument 1;

[0029] The limiting sleeve 8 is sleeved on the front end outer wall of the downhole video imaging instrument 1;

[0030] The front end of the water outlet structure 9 and the pressure differential structure body 7 are fixed in the front end fixing hole of the downhole video imaging instrument 1 through four sets of body fixing screws 13;

[0031] There are 4 groups of righting springs 4, the upper ends of which are fixed to the upper fixing ring 3 of the springs by the upper fixing screws 10 of the righting springs, and the lower ends are fixed to the lower fixing structure 6 of the springs by the lower screws 12 of the righting springs;

[0032] The straightening spring piece has a certain elastic deformation range, which can adapt to the change of the inner diameter of the wellbore within a certain range. The fixing ring 3 on the spring piece is independent of the downhole video imaging instrument 1. When the inner diameter of the wellbore is reduced, the fixing ring 3 on the spring piece can move upward along the downhole video imaging instrument 1 for a certain distance.

[0033] The limiting ring 5 and the main body fixing screw 13 ensure that the connection between the pressure differential structure main body 7 and the downhole video imaging instrument 1 is tightened during the lifting and lowering process;

[0034] After installation, the water outlet structure 9 cannot block the imaging of the lens of the downhole video imaging instrument.

[0035] Working principle:

[0036] Before performing the video imaging operation of the oil and gas wellbore, the pressure differential downhole video imaging instrument lens cleaning device is installed at the front end of the downhole video imaging instrument 1 according to the connection relationship. The downhole inspection is carried out according to the normal logging process. If the lens is not blocked by oil, foreign matter, etc. during the inspection process, the pressure differential downhole video imaging instrument lens cleaning device does not affect the normal video imaging inspection; if the imaging lens is attached with oil, foreign matter, etc. and blocks the line of sight, the operator can lift the instrument for a distance to avoid the observation area, and then quickly lift the instrument. During the lifting process, the well fluid passes through the pressure differential flushing device. Due to the design of a large inlet and a small outlet, a pressure difference will be generated. This pressure difference increases the flow rate of the well fluid, and the well fluid sprays out from around the lens to clean the instrument lens. The screen is previewed in real time through the ground video until the oil, foreign matter, etc. in front of the lens are washed away and the lifting is stopped. If the lifting distance is limited, the lifting and flushing operation can be repeated many times until the lens is clean, and then the instrument is lowered for video imaging inspection of the target position.

[0037] In summary, the present invention sets a pressure differential structure body outside the downhole video imaging instrument, and utilizes the pressure differential of the larger well fluid inlet and outlet and the smaller outlet as well as the pressure differential of the conical inner cavity, so that the downhole video imaging instrument can spray well fluid to clean the lens when it is quickly lifted up; thus, when the lens is contaminated during downhole operation, the present invention can shorten the operation cycle and improve the operation efficiency compared to lifting the instrument to the ground for cleaning. Compared with the method of collecting liquid underground and lifting up for flushing, the present invention is simple to operate, can continuously flush the lens, and avoids repeatedly lifting and lowering to disturb the original wellbore well fluid environment and make the well fluid turbid. Therefore, the present invention reduces the interference with the well fluid environment, shortens the operation cycle, and improves the efficiency of downhole detection.

[0038] It should be emphasized that the above are only preferred embodiments of the present invention and do not limit the present invention in any form. Any simple modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention are still within the scope of the technical solution of the present invention.

Claims

1. A pressure differential downhole video imaging instrument lens cleaning device, characterized in that: include: A downhole video imaging instrument (1) and a pressure differential structure body (7); the downhole video imaging instrument (1) is cylindrical, and a downhole video imaging instrument lens (2) is provided on the cylindrical front end surface of the downhole video imaging instrument (1); the pressure differential structure body (7) is cylindrical, and the pressure differential structure body (7) is coaxially sleeved outside the cylindrical side wall of the downhole video imaging instrument (1); an annular inner cavity (14) is provided in the pressure differential structure body (7); The tube mouth of the pressure differential structure body (7) located on one side of the downhole video imaging instrument lens (2) does not block the downhole video imaging instrument lens (2), and the pressure differential structure body (7) is detachably connected to the downhole video imaging instrument (1); The inner cavity (14) is provided with a nozzle (15) at one end of the downhole video imaging instrument lens (2), the nozzle (15) is connected to the inside and outside of the inner cavity (14), and the spraying direction of the nozzle (15) is toward the downhole video imaging instrument lens (2); A liquid collecting port (16) is provided at one end of the inner cavity (14) away from the lens (2) of the downhole video imaging instrument. The liquid collecting port (16) communicates with the inside and outside of the inner cavity (14). The opening direction of the liquid collecting port (16) is upward along the axial direction of the downhole video imaging instrument (1); The effective liquid flow area of ​​the liquid collecting port (16) is more than five times greater than the effective liquid flow area of ​​the nozzle (15).

2. A pressure differential downhole video imaging instrument lens cleaning device according to claim 1, characterized in that: The inner cavity (14) is shaped like a cone that is larger at the top and smaller at the bottom. The nozzle (15) is located at the small end of the cone, and the liquid collection port (16) is located at the large end of the cone.

3. A pressure differential downhole video imaging instrument lens cleaning device according to claim 2, characterized in that: The nozzle (15) is in the shape of a ring; the nozzle (15), the inner cavity (14), and the pressure differential type structural body (7) rotate on the same axis.

4. The pressure differential downhole video imaging instrument lens cleaning device according to claim 1, characterized in that: A plurality of nozzles (15) are provided, and the nozzles (15) are coaxially distributed in a ring shape around the downhole video imaging instrument lens (2).

5. A pressure differential downhole video imaging instrument lens cleaning device according to claim 4, characterized in that: The lower end surface of the pressure differential structure body (7) is in the shape of an annular step, and the nozzle (15) is located on the inner side wall of the annular step of the lower end surface of the pressure differential structure body (7).

6. A pressure differential downhole video imaging instrument lens cleaning device according to claim 4, characterized in that: The lower end surface of the pressure differential structure body (7) is flush with the shooting end of the downhole video imaging instrument lens (2), and the nozzle (15) is in the shape of a curved tube protruding from the lower end surface of the pressure differential structure body (7). The injection channel in the nozzle (15) bends from the inner cavity (14) and then faces the downhole video imaging instrument lens (2).

7. A pressure differential downhole video imaging instrument lens cleaning device according to claim 4, characterized in that: The liquid collecting port (16) is annular and is located at the upper end surface of the pressure differential structure body (7). The liquid collecting port (16) is arranged around the downhole video imaging instrument (1).

8. The pressure differential downhole video imaging instrument lens cleaning device according to claim 1, characterized in that: The upper end of the pressure differential structure body (7) is provided with a righting spring sheet (4), which is a strip-shaped elastic deformation sheet. The middle part of the righting spring sheet (4) bulges radially outwards. The lower end of the righting spring sheet (4) is detachably connected to the upper part of the pressure differential structure body (7), and the upper end of the righting spring sheet (4) is slidably connected to the outer circumference of the downhole video imaging instrument (1).

9. A pressure differential downhole video imaging instrument lens cleaning device according to claim 8, characterized in that: The straightening spring pieces (4) are provided with three to six pieces, the upper ends of the straightening spring pieces (4) are fixedly connected to the outer circumference of the spring piece upper fixing ring (3), the inner ring of the spring piece upper fixing ring (3) is slidably sleeved on the outer circumference of the downhole video imaging instrument (1), and the three to six straightening spring pieces (4) are evenly distributed around the outer circumference of the downhole video imaging instrument (1).

10. The pressure differential downhole video imaging instrument lens cleaning device according to claim 1, characterized in that: A filter screen is provided at the liquid collection port (16).

Images