A differential pressure type downhole video imaging instrument lens cleaning device

Abstract

The present application belongs to the technical field of oil and gas well observation, and relates to a differential pressure type downhole video imaging instrument lens cleaning device, which comprises a downhole video imaging instrument and a differential pressure type structure main body; the differential pressure type structure main body is sleeved on the outer side wall of the downhole video imaging instrument; an inner cavity is provided with a nozzle at one end of the downhole video imaging instrument lens, and a liquid collecting port is provided at the other end of the inner cavity away from the downhole video imaging instrument lens; the liquid effective flow area of the liquid collecting port is larger than that of the nozzle; by using the differential pressure of the larger inlet and smaller outlet of the well fluid, the downhole video imaging instrument can spray well fluid to clean the lens when being rapidly pulled up; the present application shortens the operation cycle, improves the operation efficiency, and has the advantages of simple operation, continuous lens flushing, and disturbance to the original wellbore fluid environment caused by repeated pulling up and lowering, and turbidity of the well fluid.

Description

Technical Field

[0001] This invention belongs to the field of oil and gas well observation technology, specifically relating to a lens cleaning device for a differential pressure downhole video imaging instrument. Background Technology

[0002] During downhole operations in oil and gas wells, abnormal conditions such as deformation, damage, and blockage may occur in the wellbore, preventing normal downhole operations. Therefore, it is necessary to identify the specific problems in the wellbore and then take corresponding measures to address them and restore the wellbore to normal operation. Downhole video imaging instruments for oil and gas wells operate based on the principle of visible light imaging. Their front end is equipped with a camera to acquire images of the wellbore, providing a direct and clear understanding of wellbore problems and offering objective and accurate data for subsequent operational measures. However, the downhole environment of oil and gas wells is complex, and the well fluid may contain oil, impurities, and other substances that are detrimental to imaging detection, affecting the imaging effect. If the camera lens is obstructed by impurities, oil, or other foreign objects, it will be impossible to acquire video images of the wellbore. Existing solutions involve removing the detection instrument from the oil and gas wellbore after the lens has been cleaned on the surface, and then lowering it back down for detection. Utility model CN202322888470 describes a method that uses a piston mechanism to lower and collect liquid into a cavity, and then uses the piston to push the liquid to flush the lens when the instrument is pulled up.

[0003] However, when the camera lens is contaminated, the testing instrument is lifted from the oil and gas wellbore, the lens is cleaned on the ground, and then lowered back down for testing. This repeated lowering raises the possibility of further contamination, making the operation cycle uncontrollable, reducing efficiency, and increasing costs. The utility model CN202322888470 uses a piston mechanism to lower and collect liquid into a chamber, then lifts the piston to flush the lens. However, each lowering only collects liquid up to the chamber's volume. If the liquid is not completely flushed, multiple lifting and lowering of the instrument are required, resulting in low flushing efficiency. Furthermore, the lifting and lowering process causes impurities in the wellbore to change from a static state to a suspended state, making the wellbore environment turbid and hindering imaging observation.

[0004] Therefore, there is a need for a lens cleaning device or method that can continuously and repeatedly rinse the lens to ensure it is clean, minimize interference with the well fluid environment, shorten the operation cycle, and is simple to operate, in order to solve the above-mentioned technical problems. Summary of the Invention

[0005] To solve the above-mentioned technical problems, the present invention provides the following technical solution: a differential pressure downhole video imaging instrument lens cleaning device, comprising: a downhole video imaging instrument and a differential pressure structure body; the downhole video imaging instrument is cylindrical, and a lens of the downhole video imaging instrument is provided on the front end face of the cylindrical downhole video imaging instrument; the differential pressure structure body is cylindrical, and the differential pressure structure body is coaxially sleeved on the outer side wall of the cylindrical downhole video imaging instrument; the differential pressure structure body has an annular inner cavity, and the inner cavity is coaxial with the differential pressure structure body;

[0006] The differential pressure structure body has an opening on one side of the downhole video imaging instrument lens that does not obstruct the lens. The differential pressure structure body is detachably connected to the downhole video imaging instrument. The inner cavity has a nozzle at one end of the downhole video imaging instrument lens, which connects the inside and outside of the inner cavity. The nozzle sprays towards the downhole video imaging instrument lens. The inner cavity has a liquid collection port at the end away from the downhole video imaging instrument lens, which connects the inside and outside of the inner cavity. The opening direction of the liquid collection port is upward along the axis of the downhole video imaging instrument.

[0007] The effective liquid flow area of ​​the sump is more than five times larger than that of the nozzle. When it is necessary to clean the lens of the downhole video imaging instrument, the downhole video imaging instrument is quickly lifted. Because the effective liquid flow area of ​​the sump is more than five times larger than that of the nozzle, a pressure difference is generated, which causes the well fluid in the inner cavity to be ejected from the inner cavity through the nozzle. At the same time, the external well fluid flows into the inner cavity from the sump, so that the well fluid at the nozzle can continuously clean the lens of the downhole video imaging instrument.

[0008] Preferably, the inner cavity is shaped like a cone, wider at the top and narrower at the bottom, with the nozzle located at the narrow end and the liquid collection port located at the wide end. The cone-shaped inner cavity can generate a greater pressure difference when the downhole video imaging instrument is quickly lifted, thus enhancing the cleaning effect.

[0009] More preferably, the nozzle is annular, and the nozzle, inner cavity, and differential pressure structure body are on the same rotation axis. Since the nozzle is annular and the spray direction of the nozzle is towards the lens of the downhole video imaging instrument, when the external well fluid flows into the inner cavity from the collection port and then sprays out from the nozzle from the inner cavity, the annularly sprayed well fluid directly washes the lens of the downhole video imaging instrument, so that the well fluid at the nozzle can continuously clean the lens of the downhole video imaging instrument.

[0010] Preferably, the nozzles are provided in multiples, and the nozzles are evenly distributed in a ring around the lens of the downhole video imaging instrument; the evenly distributed ring nozzles can make the well fluid cleaning area more uniform and eliminate cleaning dead corners.

[0011] More preferably, the lower end face of the differential pressure structure body is annularly stepped, and the nozzle is located on the inner wall of the annular step on the lower end face of the differential pressure structure body; the nozzle is located on the inner wall of the stepped annular step, so that the nozzle will not directly contact the well wall when the downhole video imaging instrument lens is lowered, thus preventing damage or blockage of the nozzle.

[0012] More preferably, the lower end face of the differential pressure structure body is flush with the shooting end of the downhole video imaging instrument lens, and the nozzle is a curved tube protruding from the lower end face of the differential pressure structure body. The spray channel inside the nozzle bends outward from the inner cavity and faces the downhole video imaging instrument lens. The nozzle protrudes axially from the shooting end face of the downhole video imaging instrument lens. Therefore, the nozzle can provide a certain degree of protection for the downhole video imaging instrument lens, preventing the end face of the downhole video imaging instrument lens from directly colliding with large particles of debris or the well wall. The internal spray pipe of the nozzle bends and rotates back to the end face of the downhole video imaging instrument lens. The curved pipeline reduces the head loss of the cleaning fluid and avoids the loss of water pressure caused by bending.

[0013] More preferably, the liquid collection port is annular and located on the upper end face of the differential pressure structure body, and the liquid collection port is arranged around the downhole video imaging instrument; the annular liquid collection ports evenly distributed on the upper end face can more effectively collect well fluid and prevent the pressure difference from decreasing due to insufficient well fluid or uneven inflow.

[0014] Preferably, the upper end of the differential pressure structure body is provided with a centralizing spring, which is a strip-shaped elastic deformation sheet. The middle part of the centralizing spring bulges outward along the radial direction. The lower end of the centralizing spring is detachably connected to the upper part of the differential pressure structure body, and the upper end of the centralizing spring is slidably connected to the outer circumference of the downhole video imaging instrument.

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

[0016] Preferably, a filter screen is provided at the liquid collection 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 this invention are:

[0018] 1. When the lens is contaminated during downhole operations, this invention shortens the operation cycle and improves operation efficiency compared to raising the instrument to the surface for cleaning. Compared to the method of lowering the instrument downhole to collect liquid and then raising it to rinse, this invention is simple to operate, allows for continuous rinsing of the lens, and avoids repeatedly raising and lowering the instrument, which disturbs the original well fluid environment and makes the well fluid turbid.

[0019] 2. The device of this invention is independent of the downhole video imaging detection instrument, which is easy to carry and transport. It can be equipped with a suitable differential pressure flushing device according to different instrument diameters, and has high adaptability. At the same time, different water outlet designs can be selected as needed to reduce the cost of remanufacturing the instrument.

[0020] 3. This invention is environmentally friendly throughout the entire cleaning process, reducing pollution to the well and the surrounding environment. Attached Figure Description

[0021] Figure 1 This is a structural diagram of a differential pressure downhole video imaging instrument lens cleaning device according to the present invention;

[0022] Figure 2 This is a perspective view of the present invention;

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

[0024] In the diagram, 1. Downhole video imaging instrument; 2. Downhole video imaging instrument lens; 3. Upper fixing ring of the spring; 4. Centralizing spring; 5. Limiting ring; 6. Lower fixing structure of the spring; 7. Main body of the differential pressure structure; 8. Limiting sleeve; 9. Water outlet structure; 10. Upper fixing screw of the centralizing spring; 11. Fixing screw of the limiting ring; 12. Screw of the lower section of the centralizing spring; 13. Main body fixing screw; 14. Inner cavity; 15. Nozzle; 16. Liquid collection port. Detailed Implementation

[0025] The related technologies of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0026] like Figures 1-3 As shown in this embodiment, a differential pressure downhole video imaging instrument lens cleaning device is provided. This device can clean downhole video imaging instrument lenses, and it is simple to operate and has continuous and multiple cleaning capabilities.

[0027] The differential pressure 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 a spring fixing ring 3, a straightening spring 4, a limiting ring 5, a spring lower fixing structure 6, a differential pressure structure body 7, a limiting sleeve 8, a water outlet structure 9, a straightening spring upper fixing screw 10, a limiting ring fixing screw 11, a straightening spring lower section screw 12, and a body fixing screw 13.

[0028] The limiting ring 5 is fixed to the outer wall of the downhole video imaging instrument 1 by 4 sets of limiting ring fixing screws 11, and the limiting 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 mounted on the outer wall of the front end of the downhole video imaging instrument 1;

[0030] The front ends of the water outlet structure 9 and the differential pressure structure main body 7 are fixed in the front fixing holes of the downhole video imaging instrument 1 by four sets of main body fixing screws 13.

[0031] There are 4 sets of straightening springs 4. The upper end of the spring is fixed to the fixing ring 3 on the spring by the upper fixing screw 10, and the lower end is fixed to the lower fixing structure 6 on the spring by the lower fixing screw 12.

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

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

[0034] After installation, the water outlet structure 9 must not obstruct the imaging of the downhole video imaging instrument lens.

[0035] Working principle:

[0036] Before conducting wellbore video imaging operations on oil and gas wells, install the differential pressure downhole video imaging instrument lens cleaning device at the front end of the downhole video imaging instrument 1 according to the connection relationship. Follow the normal logging process for downhole inspection. If the lens is not obstructed by oil, foreign objects, etc., the differential pressure downhole video imaging instrument lens cleaning device will not affect normal video imaging inspection. If the imaging lens is covered by oil, foreign objects, etc., obstructing the view, the operator can lift the instrument a short distance to avoid the observation area, and then quickly lift the instrument again. During the lifting process, the well fluid passes through the differential pressure flushing device. Due to the design of a large inlet and a small outlet, a pressure difference is generated. This pressure difference increases the well fluid flow rate, and the well fluid sprays out from around the lens, cleaning the instrument lens. The image is previewed in real time via ground video until the oil, foreign objects, etc., in front of the lens are washed away and lifting stops. If the lifting distance is limited, the lifting and flushing operation can be repeated multiple times until the lens is clean, and then the instrument is lowered again for video imaging inspection of the target location.

[0037] In summary, this invention, by incorporating a differential pressure structure on the outside of the downhole video imaging instrument, utilizes the pressure difference between the large inlet and outlet of the well fluid and the small outlet, along with the pressure difference within the conical inner cavity, to allow well fluid to be ejected to clean the lens during rapid lifting of the downhole video imaging instrument. This enables the instrument to be cleaned by spraying well fluid when the lens becomes contaminated during downhole operations, compared to lifting the instrument to the surface for cleaning. This invention shortens the operation cycle and improves operational efficiency. Compared to the method of lowering the instrument downhole to collect fluid and then lifting it up to rinse, this invention is simpler to operate and allows for continuous lens rinsing, avoiding repeated lifting and lowering that disrupts the original well fluid environment and causes turbidity. Therefore, this invention reduces 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 merely preferred embodiments of the present invention and are not intended to limit the present invention in any way. Any simple modifications, equivalent changes and alterations made to the above embodiments based on the technical essence of the present invention shall still fall within the scope of the technical solution of the present invention.

Claims

1. A lens cleaning device for a differential pressure downhole video imaging instrument, characterized in that, include: The downhole video imaging instrument (1) and the differential pressure structure body (7) are provided. The downhole video imaging instrument (1) is cylindrical, and the downhole video imaging instrument lens (2) is provided on the front end face of the cylindrical part of the downhole video imaging instrument (1). The differential pressure structure body (7) is cylindrical, and the differential pressure structure body (7) is coaxially sleeved on the outside of the cylindrical side wall of the downhole video imaging instrument (1). The differential pressure structure body (7) is provided with an annular inner cavity (14). The opening of the differential pressure structure (7) located on one side of the downhole video imaging instrument lens (2) does not obstruct the downhole video imaging instrument lens (2), and the differential pressure structure (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) connects the inside and outside of the inner cavity (14), and the spray direction of the nozzle (15) is towards the downhole video imaging instrument lens (2). The inner cavity (14) is provided with a liquid collection port (16) at one end away from the lens (2) of the downhole video imaging instrument. The liquid collection port (16) connects the inside and outside of the inner cavity (14). The opening direction of the liquid collection port (16) is upward along the axis of the downhole video imaging instrument (1). The effective liquid flow area of ​​the liquid collection port (16) is more than five times greater than the effective liquid flow area of ​​the nozzle (15); The inner cavity (14) is shaped like a cone, which 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. The nozzle (15) is annular, and the nozzle (15), the inner cavity (14), and the differential pressure structure body (7) are on the same rotation axis; The nozzle (15) is provided in multiple ways, and the nozzle (15) is evenly distributed in a ring and coaxially around the lens (2) of the downhole video imaging instrument; The upper end of the differential pressure structure body (7) is provided with a centralizing spring (4). The centralizing spring (4) is a strip-shaped elastic deformation sheet. The middle part of the centralizing spring (4) bulges outward along the radial direction. The lower end of the centralizing spring (4) is detachably connected to the upper part of the differential pressure structure body (7). The upper end of the centralizing spring (4) is slidably connected to the outer circumference of the downhole video imaging instrument (1).

2. The lens cleaning device for a differential pressure downhole video imaging instrument according to claim 1, characterized in that, The lower end face of the differential pressure structure (7) is an annular step, and the nozzle (15) is located on the inner side wall of the annular step on the lower end face of the differential pressure structure (7).

3. The lens cleaning device for a differential pressure downhole video imaging instrument according to claim 1, characterized in that, The lower end face of the differential pressure structure body (7) is flush with the shooting end of the downhole video imaging instrument lens (2). The nozzle (15) is a curved tube protruding from the lower end face of the differential pressure structure body (7). The injection channel inside the nozzle (15) bends from the inner cavity (14) and faces the downhole video imaging instrument lens (2).

4. The lens cleaning device for a differential pressure downhole video imaging instrument according to claim 1, characterized in that, The liquid collection port (16) is annular and located on the upper end face of the differential pressure structure body (7). The liquid collection port (16) is arranged around the downhole video imaging instrument (1).

5. A lens cleaning device for a differential pressure downhole video imaging instrument according to claim 1, characterized in that, The straightening spring (4) is provided with three to six pieces. The upper end of the straightening spring (4) is fixedly connected to the outer circumference of the fixing ring (3) on the spring. The inner ring of the fixing ring (3) on the spring slides around the outer circumference of the downhole video imaging instrument (1). The three to six straightening springs (4) are evenly distributed around the outer circumference of the downhole video imaging instrument (1).

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

Images