A laser remote ignition cutting system for oil and gas wells and its application method

Abstract

This invention relates to a laser remote on-fire cutting system and its method for use in oil and gas wells, belonging to the field of oil and gas well emergency repair technology. The system includes a first mobile platform away from the wellhead and a second mobile platform close to the wellhead. The first mobile platform is equipped with a laser for outputting laser light, and the second mobile platform is equipped with a protective shell. The protective shell is equipped with a laser cutting head. The laser light is transmitted to the laser cutting head and output to the wellhead to achieve on-fire cutting. This invention can realize laser remote on-fire cutting without the need for personnel to operate near the wellhead, thus improving safety.

Description

Technical Field

[0001] This invention belongs to the field of oil and gas well emergency repair technology, specifically relating to a laser remote ignition cutting system for oil and gas wells and its usage method. Background Technology

[0002] During oil and gas field development, blowout accidents can occur during drilling, oil testing, gas testing, and oil and gas production. After a blowout and subsequent fire, the high oil and gas pressure and production rate within the well result in a fierce fire that damages the derrick, drilling rig, drilling tools, wellhead equipment, diesel engine, drilling pump, solids control equipment, and other components. Equipment, instruments, and materials around the wellhead are also burned and deformed, accumulating at the well site. To effectively control a blowout and fire, it is essential to clear and cut away the damaged old wellhead equipment and install new equipment.

[0003] Due to the high temperatures, water spray, smoke, and challenging terrain at the fire site, visibility for clearing and cutting operations was extremely poor, resulting in insufficient accuracy of observation and a high risk of errors during cutting. This led to slow progress and low efficiency in the rescue and cutting work. Furthermore, close-range observation and command of cutting by personnel at the wellhead presented significant limitations. Even with strict protective measures, close-range rescue operations still posed numerous safety hazards and posed a high risk of injury to personnel, compromising their safety. Summary of the Invention

[0004] In order to address the shortcomings of existing technologies and solve the aforementioned problems, a laser remote ignition cutting system for oil and gas wells and its application method are proposed.

[0005] To achieve the above objectives, the present invention provides the following technical solution:

[0006] In a first aspect, the present invention provides a laser remote ignition cutting system for oil and gas wells, comprising:

[0007] A first mobile platform located away from the wellhead, equipped with a laser for outputting laser light;

[0008] And a second mobile platform near the wellhead, the second mobile platform is equipped with a protective shell, the protective shell is equipped with a laser cutting head, the laser is transmitted to the laser cutting head and output to the wellhead to achieve on-fire cutting.

[0009] The technical solution is further configured such that the laser includes a pulsed laser and a continuous laser, and the pulsed laser output from the pulsed laser and the continuous laser output from the continuous laser are combined to form a composite laser.

[0010] The technical solution is further configured such that there are multiple continuous lasers, and the multiple continuous lasers output continuous lasers with the same wavelength.

[0011] The technical solution is further configured such that a flexible pipeline connects the first mobile platform and the second mobile platform, and the flexible pipeline contains a laser transmission optical fiber, a gas line, a coolant line, and an electrical connection line.

[0012] The technical solution is further configured such that the first mobile platform is also equipped with a gas source and a coolant tank, the gas line is connected to the gas source and the laser cutting head respectively, the coolant line is connected to the coolant tank and the protective shell respectively, and the laser transmission optical fiber is connected to the laser and the laser cutting head respectively.

[0013] The technical solution is further configured such that one end of the laser cutting head extends into the interior of the protective shell and serves as an input end, the input end is provided with an illumination source, and a high-pressure gas pipe connected to a gas line is provided near the input end of the laser cutting head.

[0014] The technical solution is further configured such that the protective housing is provided with an optical path transmission element and an optical monitoring element, the laser output from the laser transmission fiber is transmitted to the laser cutting head by the optical path transmission element, and the optical monitoring element is set corresponding to the input end.

[0015] The technical solution is further configured such that the optical path transmission element includes a collimating output head, a first reflector and a second reflector. The collimating output head is connected to the laser transmission fiber. The second reflector is tilted and its optical axis coincides with the central axis of the laser cutting head. The first reflector and the second reflector are arranged parallel to each other.

[0016] The technical solution is further configured such that the optical monitoring element is located on the side of the second reflector away from the laser cutting head, and a narrow-band filter with a center wavelength matching the illumination light wavelength is provided between the optical monitoring element and the second reflector.

[0017] The technical solution is further configured such that the interior of the protective shell is provided with a cooling channel connected to the coolant line, and the protective shell is provided with a spray pipe connected to the cooling channel, and the spray pipe has spray holes for spraying coolant toward the outer surface of the protective shell.

[0018] The technical solution is further configured such that the wellhead is equipped with guide rails, and the second mobile platform is a tracked platform.

[0019] The technical solution is further configured such that the outer surfaces of the flexible pipeline, the laser cutting head, and the protective shell are provided with a heat insulation layer and a high-temperature impact resistant layer from the inside to the outside.

[0020] Secondly, the present invention provides a method for using a laser remote ignition cutting system for oil and gas wells, comprising the following steps:

[0021] Before cutting, the first moving platform moves to a position away from the wellhead, and the second moving platform delivers the laser cutting head to a position close to the wellhead;

[0022] During cutting, the laser cutting head outputs a composite laser to the outer surface of the wellhead. The second moving platform moves around the wellhead, performing a first cut to form a first cutting slit, the depth of which is less than the wall thickness of the wellhead. The laser cutting head then outputs a continuous laser to the outer surface of the wellhead. The second moving platform moves around the wellhead, performing a second cut based on the first cutting slit to form a second cutting slit. The sum of the depths of the first and second cutting slits is equal to the wall thickness of the wellhead. The first cutting slit is a closed annular cutting slit, and the second cutting slit is a non-closed annular cutting slit. Under the pressure of the fluid inside the well, the wellhead tilts towards the direction where the second cutting slit has not yet formed.

[0023] The technical solution is further configured such that both the composite laser and the continuous laser are rectangular light spots, with the long side of the rectangular light spot parallel to the axial direction of the wellhead and the wide side of the rectangular light spot parallel to the radial direction of the wellhead.

[0024] The technical solution is further configured such that, during the formation of the first cutting seam, the composite laser scans the wellhead circumferentially multiple times, the longitudinal section of the first cutting seam is an isosceles trapezoid, and the depth of the first cutting seam is 20mm-30mm less than the wall thickness of the wellhead.

[0025] The technical solution is further configured such that, during the formation of the second cutting seam, the continuous laser scans circumferentially along the wellhead in a single pass, and the angle between the continuous laser and the first cutting seam is 40°-50°.

[0026] The technical solution is further configured such that, along the circumference of the wellhead, the circumference where the second cutting slit is not formed is 1 / 3 of the wellhead circumference.

[0027] The beneficial effects of this invention are:

[0028] 1. The second mobile platform transports the laser cutting head closer to the wellhead, while the first mobile platform carries the laser away from the wellhead, realizing remote laser cutting with flame, eliminating the need for personnel to operate near the wellhead and improving safety.

[0029] 2. The laser cutting head has a visualization function, which effectively solves the problem of the influence of harsh conditions in the cutting area on the cutting beam and illumination light, and can provide a clear optical image to achieve visualization, thereby effectively improving the efficiency of cutting and obstacle removal operations.

[0030] 3. The protective shell adopts dual cooling and has good temperature resistance to adapt to high-temperature fire environments and enable near-wellhead emergency operations.

[0031] 4. Using composite lasers to thin the wellhead, the cutting amount is precisely controlled based on visualization, and continuous lasers are used to cut the wellhead, achieving high-efficiency cutting of the wellhead.

[0032] 5. The second mobile platform deflects around the wellhead at an angle, causing continuous laser tilting to cut the wellhead and preventing the high-pressure jet gas from affecting the cutting. Attached Figure Description

[0033] Figure 1 This is a schematic diagram of the laser remote ignition cutting system for oil and gas wells in this invention;

[0034] Figure 2 This is a cross-sectional view of the protective outer casing in this invention;

[0035] Figure 3 This is a schematic diagram of the optical path transmission element in this invention;

[0036] Figure 4 This is a schematic diagram of the wellhead cutting changes in this invention;

[0037] Figure 5 This is a schematic diagram of the composite laser cutting wellhead in this invention;

[0038] Figure 6 This is a schematic diagram of continuous laser cutting of the wellhead in this invention;

[0039] Figure 7 This is a schematic diagram of the first cutting slit and the second cutting slit in this invention.

[0040] In the attached diagram: 1-First moving platform, 2-Second moving platform, 3-Protective shell, 4-Laser cutting head, 5-Wellhead, 6-Flexible pipeline, 7-Spray pipe, 8-Pulsed laser, 9-Continuous laser, 10-Gas source, 11-Coolant tank, 12-Cooling channel, 13-Ceramic fiber layer, 14-Mullite layer, 15-Zirconium oxide ceramic layer, 16-Yttrium oxide ceramic layer, 17-Collimating output head, 18-Focusing lens, 19-First reflecting mirror, 20-Second reflecting mirror, 21-Narrow band filter, 22-Optical monitoring element, 23-Illumination source, 24-Guide rail, 25-First cutting slit, 26-Second cutting slit. Detailed Implementation

[0041] To enable those skilled in the art to better understand the technical solutions of the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings. Based on the embodiments in this application, other similar embodiments obtained by those skilled in the art without creative effort should all fall within the scope of protection of this application. Furthermore, directional terms mentioned in the following embodiments, such as "up," "down," "left," and "right," are only for reference to the directions in the accompanying drawings; therefore, the directional terms used are for illustrative purposes and not for limiting the invention.

[0042] Example 1:

[0043] like Figures 1 to 3 As shown, a laser remote-controlled flaming cutting system for oil and gas wells includes a first mobile platform 1 and a second mobile platform 2. The first mobile platform 1 uses a wheeled drive chassis and is positioned away from the wellhead 5, for example, at a distance of 200m. The second mobile platform 2 uses a tracked drive chassis and is positioned close to the wellhead 5, for example, at a distance of 2m.

[0044] The first mobile platform 1 is equipped with a laser for outputting laser light, an air source 10, and a coolant tank 11. Specifically, the laser includes a pulsed laser 8 and a continuous laser 9. The pulsed laser output by the pulsed laser 8 and the continuous laser output by the continuous laser 9 are combined to form a composite laser.

[0045] Preferably, multiple continuous lasers 9 can be provided, and multiple continuous lasers 9 output continuous lasers with the same wavelength. After the multiple continuous lasers are combined for the first time, they are combined with the pulsed laser for the second time.

[0046] Specifically, the second mobile platform 2 is equipped with a protective shell 3, and the protective shell 3 is equipped with a laser cutting head 4. The laser is transmitted to the laser cutting head 4 and output to the wellhead 5 to realize remote laser cutting with flame.

[0047] Correspondingly, a flexible pipeline 6 connects the first mobile platform 1 and the second mobile platform 2. The flexible pipeline 6 contains a laser transmission fiber, a gas line, a coolant line, and electrical connection lines. Preferably, the flexible pipeline 6 is a corrugated pipe. It is worth noting that the gas line connects to the gas source 10 and the laser cutting head 4, respectively, for supplying high-pressure gas to the laser cutting head 4. The coolant line connects to the coolant tank 11 and the protective shell 3, respectively, for supplying coolant to the protective shell 3. The laser transmission fiber connects to the laser and the laser cutting head 4, with the laser positioned away from the wellhead 5 to achieve remote laser transmission.

[0048] Specifically, the laser cutting head 4 has an internal cavity. At the same time, one end of the laser cutting head 4 extends into the interior of the protective shell 3 and serves as an input end. A high-pressure gas pipe connected to a gas line is provided near the input end of the laser cutting head 4. The high-pressure gas flow is delivered to the cavity of the laser cutting head 4 through the high-pressure gas pipe.

[0049] Meanwhile, the input end is equipped with an illumination source 23 and an optical window 5. The surface of the optical window 5 is coated with a high-transmittance film for laser and illumination light, realizing the output of illumination light and laser. Preferably, multiple illumination sources 23 are arranged along the circumference of the laser cutting head 4.

[0050] Specifically, the protective housing 3 is equipped with an optical path transmission element and an optical monitoring element 22. The laser output from the laser transmission fiber is transmitted to the laser cutting head 4 by the optical path transmission element, and the optical monitoring element 22 is set corresponding to the input end.

[0051] It is worth noting that the optical path transmission element includes a collimating output head 17, a focusing lens 18, a first reflecting mirror 19, and a second reflecting mirror 20. The collimating output head 17 is connected to the laser transmission fiber to collimate the laser beam. The collimated beam is then transmitted sequentially through the focusing lens 18 to the first reflecting mirror 19, the second reflecting mirror 20, and the laser cutting head 4. The second reflecting mirror 20 is tilted, and its optical axis coincides with the central axis of the laser cutting head 4. The first reflecting mirror 19 and the second reflecting mirror 20 are arranged parallel to each other.

[0052] Specifically, the optical monitoring element 22 is located on the side of the second reflector 20 away from the laser cutting head 4. Preferably, the optical monitoring element 10 is an infrared camera, an industrial camera, and / or a 3D contour laser scanner. A narrow-band filter 21 with a center wavelength matching the illumination light wavelength is provided between the optical monitoring element 22 and the second reflector 20, allowing only the illumination light to pass through, while laser light and other wavelengths of light (combustion flames, infrared radiation) cannot pass through. Simultaneously, the surface of the second reflector 20 is coated with a high-transmittance film for both laser light and illumination light.

[0053] In use, the illumination light is output to the cutting area through the laser cutting head 4 and reflected back to the optical monitoring element 22 to construct an environmental image of the cutting area. At the same time, under the action of high-pressure airflow, the adverse conditions in the cutting area are effectively resolved to address the impact of the laser and illumination light on the laser. This provides a clear optical image, enables visualization, solves the problems of blind cutting and repeated cutting, effectively improves the efficiency of cutting and obstacle removal operations, and removes residual slag from the laser cutting area. Furthermore, the laser, illumination light, and high-pressure airflow are all emitted from the laser cutting head 4, resulting in high integration and a small footprint.

[0054] Specifically, the protective shell 3 has a cooling channel 12 connected to the coolant circuit inside. Correspondingly, the protective shell 3 has an inlet and an outlet, which are connected to the cooling channel 12. It is worth noting that coolant is injected into the cooling channel 12 through the inlet, flows through the cooling channel 12, and is output through the outlet, achieving the first layer of cooling protection for the protective shell 3. The protective shell 3 has a spray pipe 7 connected to the cooling channel 12, with spray holes on the spray pipe 7 spraying coolant towards the outer surface of the protective shell 3. It is worth noting that the coolant located in the cooling channel 12 can flow to the spray pipe 7 and be sprayed onto the outer surface of the protective shell 3 through the spray holes, cooling and dissipating heat from the outer surface of the protective shell 3, achieving the second layer of cooling protection for the protective shell 3. Simultaneously, the coolant inside the spray pipe 7 originates from the cooling channel, achieving effective utilization of the coolant.

[0055] Preferably, the spray pipe 7 is a high-temperature resistant ceramic spray pipe, with its end away from the protective shell 3 having a closed structure, and the spray holes are evenly distributed on the pipe wall of the spray pipe 7. Simultaneously, the spray pipe 7 can be evenly distributed on the top and / or side walls of the protective shell 3.

[0056] To adapt to high-temperature environments, the flexible conduit 6, the laser cutting head 4, and the protective shell 3 are provided with a heat insulation layer and a high-temperature impact-resistant layer from the inside out, providing thermal protection. Specifically, the heat insulation layer includes a mullite layer 14 and a ceramic fiber layer 13 from top to bottom. The ceramic fiber layer 13 has a layered porous structure with low thermal conductivity, providing heat insulation and cushioning. The mullite layer 14, as a flame-retardant heat insulation material, is heat-resistant, can be manufactured in large sizes, and is low in cost. The high-temperature impact-resistant layer includes a yttrium oxide ceramic layer 16 and a zirconia ceramic layer 15 from top to bottom. The yttrium oxide ceramic layer 16 provides thermal shock resistance and temperature field homogenization, while the zirconia ceramic layer 15 provides high-temperature resistance and heat insulation. The yttrium oxide ceramic layer 16 is composed of several yttrium oxide ceramic blocks, and the zirconia ceramic layer 15 is composed of several zirconia ceramic blocks.

[0057] Example 2:

[0058] like Figures 1 to 7 As shown, a method for using a laser remote-controlled ignition cutting system for oil and gas wells includes the following steps:

[0059] Before cutting, a guide rail 24 is laid near the wellhead 5. The first moving platform 1 moves to a position away from the wellhead 5, and the second moving platform 2 transports the laser cutting head 4 to a position close to the wellhead 5.

[0060] During the cutting process, firstly, the laser cutting head 4 outputs a composite laser to the outer surface of the wellhead 5. The second moving platform 2 moves back and forth around the wellhead, causing the composite laser to scan multiple times along the circumference of the wellhead, making a cut and forming a first cutting slit 25. The depth of the first cutting slit 25 is less than the wall thickness of the wellhead 5, thus achieving a thin wellhead.

[0061] Preferably, the depth of the first cutting slit 25 is 20mm-30mm less than the wall thickness of the wellhead, and the longitudinal section of the first cutting slit 25 is an isosceles trapezoid, which facilitates the entry of high-pressure airflow and improves cutting efficiency.

[0062] Then, the laser cutting head 4 outputs a continuous laser beam to the outer surface of the wellhead 5. The second moving platform 2 moves one way around the wellhead 5, causing the continuous laser to scan one way around the circumference of the wellhead 5. The angle between the continuous laser and the first cutting slit is 40°-50°. A second cutting is performed on the basis of the first cutting slit 25 to form a second cutting slit 26. The sum of the depths of the first cutting slit 25 and the second cutting slit 26 is equal to the wall thickness of the wellhead 5, thus achieving a beveled cut of the wellhead 5. The first cutting slit 25 is a closed annular cutting slit, and the second cutting slit 26 is a non-closed annular cutting slit. Under the action of fluid pressure inside the well, the wellhead 5 tilts in the direction where the second cutting slit 26 has not been formed. Preferably, along the circumference of the wellhead 5, the circumference where the second cutting slit 26 has not been formed (i.e., the pre-cut circumference) is 1 / 3 of the circumference of the wellhead 5.

[0063] It is worth noting that continuous lasers are characterized by low power density, high material thermal conduction loss, the need for long-term energy injection and accumulation, and low efficiency. Pulsed lasers, on the other hand, generate high-temperature, high-pressure steam and plasma with hydrodynamic motion creating a mechanical effect, causing ablation products to be quickly ejected and dispersed, resulting in a small removal area. When using composite lasers, continuous laser heating raises the temperature of the wellhead sidewall, reducing its Young's modulus, yield strength, and breaking strength. The high-power-density pulsed laser forms high-temperature, high-pressure steam and plasma, generating a significant mechanical effect that causes some unmelted material to detach, thus lowering the ablation temperature below the melting point. Composite lasers can create larger and deeper ablation holes, and to achieve the same ablation effect, the required laser power is significantly reduced.

[0064] Specifically, both the composite laser and the continuous laser are rectangular beams. The long side of the rectangular beam is parallel to the axial direction of the wellhead 5, resulting in a large beam divergence angle, preventing beam jamming, and achieving high power density. The wide side of the rectangular beam is parallel to the radial direction of the wellhead 5, resulting in a small beam divergence angle, which is suitable for increasing the cutting depth.

[0065] The present invention has been described in detail above. The above description is only a preferred embodiment of the present invention and should not be construed as limiting the scope of the present invention. All equivalent changes and modifications made in accordance with the scope of this application should still fall within the scope of the present invention.

Claims

1. A laser-based remote-controlled ignition cutting method for oil and gas wells, characterized in that, This method is based on a laser-based remote ignition cutting system for oil and gas wells, which includes: A first mobile platform located away from the wellhead is equipped with a laser for outputting laser light. The laser includes a pulsed laser and a continuous laser. The pulsed laser light output from the pulsed laser and the continuous laser light output from the continuous laser are combined to form a composite laser. And a second mobile platform near the wellhead, the second mobile platform is equipped with a protective shell, the protective shell is equipped with a laser cutting head, the laser is transmitted to the laser cutting head and output to the wellhead to achieve on-fire cutting; The method includes: Before cutting, the first moving platform moves to a position away from the wellhead, and the second moving platform transports the laser cutting head to a position close to the wellhead. During cutting, the laser cutting head outputs a composite laser to the outer surface of the wellhead. The second moving platform moves around the wellhead, performs a first cut, and forms a first cutting slit. The depth of the first cutting slit is less than the wall thickness of the wellhead. The laser cutting head outputs a continuous laser to the outer surface of the wellhead. The second moving platform moves around the wellhead, performs a second cut based on the first cutting slit, and forms a second cutting slit. The sum of the depths of the first and second cutting slits is equal to the wall thickness of the wellhead. The first cutting slit is a closed annular cutting slit, and the second cutting slit is a non-closed annular cutting slit. The angle between the continuous laser and the first cutting slit is 40°-50°. Under the action of the fluid pressure inside the well, the wellhead tilts towards the direction where the second cutting slit has not been formed. The circumference of the area where the second cutting slit has not been formed is 1 / 3 of the circumference of the wellhead.

2. The laser remote-controlled ignition cutting method for oil and gas wells according to claim 1, characterized in that, A flexible pipeline connects the first mobile platform and the second mobile platform. The flexible pipeline contains a laser transmission fiber, a gas line, a coolant line, and an electrical connection line.

3. The laser remote-controlled ignition cutting method for oil and gas wells according to claim 2, characterized in that, The first mobile platform is also equipped with a gas source and a coolant tank. The gas line is connected to the gas source and the laser cutting head, the coolant line is connected to the coolant tank and the protective shell, and the laser transmission fiber is connected to the laser and the laser cutting head.

4. A laser-based remote-controlled cutting method for oil and gas wells according to claim 2 or 3, characterized in that, One end of the laser cutting head extends into the interior of the protective housing and serves as an input end. The input end is equipped with an illumination source, and a high-pressure gas pipe connected to a gas line is located near the input end of the laser cutting head.

5. A laser-based remote-controlled ignition cutting method for oil and gas wells according to claim 4, characterized in that, The protective housing is equipped with an optical path transmission element and an optical monitoring element. The laser output from the laser transmission fiber is transmitted to the laser cutting head by the optical path transmission element, and the optical monitoring element is set corresponding to the input end.

6. A laser-based remote-controlled cutting method for oil and gas wells according to claim 2, characterized in that, The protective housing has a cooling channel inside that is connected to the coolant line, and a spray pipe connected to the cooling channel is provided on the protective housing. The spray pipe has spray holes that spray coolant toward the outer surface of the protective housing.

7. A laser-based remote-controlled ignition cutting method for oil and gas wells according to claim 2, characterized in that, The flexible pipeline, the laser cutting head, and the outer surface of the protective shell are provided with a heat insulation layer and a high-temperature impact resistant layer from the inside out.

8. A laser-based remote-controlled cutting method for oil and gas wells according to claim 1, characterized in that, During the formation of the first cut, the composite laser scans multiple times circumferentially along the wellhead. During the formation of the second cut, the continuous laser scans once circumferentially along the wellhead.

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