RU2776125C1 - Method for forming a monolithic drill string from casing pipes by orbital laser welding - Google Patents

Abstract

FIELD: mining industry.

SUBSTANCE: invention relates to the field of drilling with laser-welded steel pipes, namely, to the formation of a drill string by laser welding of casing steel pipes during vertical or inclined drilling of a well during oil, gas or water production, as well as during the construction of bore piles. The drill string is formed from casing pipes with the possibility of attaching a drill bit at its lower end. The upper casing pipe is brought to the lower casing pipe from above freely suspended. The welding machine is pre-installed and fixed at the free end of the lower casing pipe. The welding machine is mounted on the casing pipe by means of a two-segment annular lower girth in such a way as to provide a coaxially mounted laser single-segment orbital module of the welding machine rotating non-contact with the casing pipe above this girth at least a complete revolution around the lower girth at a distance from the edge along the casing pipe, providing partial alignment on the edge of the filler wire and radially supplied laser beam in the area of beam tightening during welding. The upper casing pipe is lowered until it comes into contact with the end face of the lower one. The girth and fixation of the end of the upper casing pipe is carried out with a two-segment upper girth, coaxial with the lower one and rigidly attached to it with a steel power arc-shaped structure, which is located outside and outside the orbital module to prevent restriction of its rotation and ensure its alignment with the grips. The winding of the energy protective cable channel hanging sideways on the body of the power structure is carried out onto the drum of the mentioned module for at least one full turn and in this position laser welding is carried out with the formation of a solid weld in at least one pass. In the process of fully automatic reverse rotation of the orbital part of the welding machine, the cable channel is unwound from the drum. At the end of the process of forming a solid weld, at least in one pass, the casing pipes are freed from the girths of the welding machine, which is taken aside.

EFFECT: improvement of the quality and strength characteristics of a monolithic drill string, an increase in its reliability, drilling speed and depth, and service life is ensured.

1 cl, 1 dwg

Description

Technical field

The invention relates to the field of drilling with laser-welded steel pipes, namely to the formation of a drill string by laser welding of casing steel pipes in vertical or inclined well drilling in the production of oil, gas or water, as well as in the construction of bored supports of bridges, platforms and high-rise buildings.

State of the art

For almost a hundred years, the method of drilling with casing string has been known: "Second wind" of drilling technology with casing string - Drilling and Oil - gas and oil magazine (bumeft.ru) WHILE DRILLING TECHNOLOGY). The first ideas to drill on a casing string arose at the beginning of the 20th century. So, in a patent from 1923, a special retrievable bit was described and 17 advantages of this technology were highlighted. The casing pipe has a larger diameter compared to drill pipes. Due to this, there is constant contact with the borehole wall. The effect of mechanical colmatation appears - drilled cuttings are pressed by the casing pipe into the walls of the well, pores and cracks are clogged, and in the case of absorption, it decreases or is completely eliminated. The presence of swelling and plastic clays, flowing salts or landslide rocks, the risk of permafrost zone thawing are common factors when drilling under a conductor or a technical casing in many fields in Russia. They lead to the next problem - the instability of the borehole walls, which leads to long-term gauges and workings. This greatly increases the construction time even of short sections. But even after all operations to prepare the hole, an accident often occurs - sticking, which can cause loss of equipment and the need to re-drill the interval. In this case, drilling on a string is also an effective solution, since the casing pipes are constantly in the well. Casing of problem intervals occurs immediately during the drilling process. Most often, standard OTTM or Buttress threads are used in casing pipes, which are designed for high tensile loads, but have low allowable torque values. To expand this limit, multi-moment unloading rings (MLT) allow. They provide a metal-to-metal stop connection and increase the allowable torque.

However, the presence of such relief rings leads to an increase in the diameter of the threaded joint and this negatively affects the depth of penetration of the well and its diameter, in addition, the strength characteristics of the threaded joint in terms of permissible torque are inferior to the welded joint, all the more laser and are critical to shock loads, which can lead to at least a breach of the tightness of the thread seal.

A similar problem arises in the construction of bored supports , casing), where casing pipes are widely used. The work is carried out by concreting the finished well. The diameter of this design can be from 300 to 1500 mm. The most popular are products with a diameter of 300 to 600 mm. For the installation of bored strings, a sectional type steel casing pipe is used. The lower section of such a column has a special drilling element that goes into the ground during percussive drilling, which causes significant axial and transverse loads on the column. The connection of this design occurs with the help of threads or sockets with all their strength shortcomings and lack of tightness. Steel pipes are in many cases connected by welding, but this is a rather laborious method.

A group of inventions RU2630327C1 is known, which relates to a method for connecting and disconnecting pipes for the production of bituminous oil and a device for laser butt welding and cutting of pipes. The technical result is to increase the reliability of the pipe string when pumping the coolant. The method for connecting and disconnecting pipes for bituminous oil production includes lowering pipes into a well with a laser welded connection and lifting pipes with laser cutting disconnection in one revolution around the junction. In this case, pipes made of low-carbon steel are used. The pipes are equipped with annular stops along the upper edge, which, when interacting with the wellhead equipment, allow interaction with laser welding and cutting so that the welding or cutting laser beam is located in the pipe joint zone when rotating around the pipes being welded or cut. When lowering into the well, the first pipe to be joined is fixed by the wellhead equipment from axial movement and rotation, limiting the departure from the well with its annular stop. The second pipe is joined end to end with the first pipe. After that, the joint area is covered with a laser welding device, focusing on the stop of the first pipe, with the possibility of rotation at a speed that allows the joined pipes to be welded qualitatively and hermetically. During the first rotation of the laser welding device, the location of the joint is controlled. At the second rotation, the pipe joint is welded with a laser, after which the quality of the weld is examined. Pipes are lowered and the second pipe is fixed due to its annular stop in the wellhead equipment. The pipe welding process is repeated until all pipes to be welded are lowered into the well. When extracting pipes from the well, the first pipe is removed from the edge, and the second is fixed by the wellhead equipment from axial movement and rotation, limiting the departure from the well with its annular stop. After that, the joint area is covered by a laser cutting device, focusing on the stop of the second pipe, with the possibility of rotation at a speed that allows high-quality cutting of the joined pipes. As the laser cutting device rotates, the pipes are cut by the laser. The first pipe is sent to pipe racks, and the second pipe is retrieved from the well. Fix the next pipe in the wellhead equipment. The pipe cutting process is repeated until the required number of pipes is removed from the well. The disadvantage of this group of inventions is the welding of specially prepared pipes with the presence of thrust rings on the outer side of the pipe, which sharply reduces the scope of the method and makes it impossible to weld and cut standard casing pipes without an annular stop. It also requires two slow bypasses of the pipe, the first one for digitizing and entering data on the edge boundary of the combined pipes into the computer program to link the welding process to the perimeter of the edges along its entire length, and the second one for the welding process itself, which slows down the process. The orbital mechanism moves over all irregularities in the pipe and vibrates due to the driven rollers in contact with the pipe, which leads to random jumps and adversely affects the quality of the weld. The location of the girths near the edges creates splashes on the rollers during welding and clogs them, and also does not provide sufficient force to keep the pipes in contact and can lead to their uncontrolled displacement, an unacceptable oblique gap will occur during welding and the quality will not be achieved. In addition, for high-quality laser welding and cutting, different specialized heads are usually used, but here they are made the same, which cannot affect the quality of the edge after cutting with a welding laser head, which is further proposed to be used again when re-welding the pipe cut in this way. Moreover, with such trimming, it is proposed to divert devices 22 and 23 - this is a nozzle with a protective gas for cutting off products and metal spatter during welding. The nozzles do not blow out or burn out the molten metal from the seam, but only blow the welding products to the side to protect the optics of the laser head. And without a strong jet of air (oxygen), which would be present in the cutting laser head, cutting with a laser beam by a welding head is ineffective and of poor quality. The invention does not apply to welding and cutting of vertically located oil steel pipes, and even more so casing pipes forming a drill string, and, with all obviousness, this implementation is impossible due to the above disadvantages.

The present invention is devoid of the above disadvantages, can be used for high-quality welding of oil steel pipes, including casing and tubing in vertical or inclined boreholes.

Disclosure of the invention The invention proposes a method for forming a monolithic drill string by connecting pipes in the drill string by orbital laser welding, namely, by making mechanical contact at the end of the welded pipes by axial alignment, in which the lower pipe is fixed with a wellhead girth in the borehole, leaving a free end, and the upper pipe is brought to the lower pipe from above for laser welding, characterized in that the drill string is formed from casing pipes with the possibility of connecting a drill-bit at its lower end, the upper casing pipe is brought to the lower casing pipe freely suspended from above, preliminary installation is carried out and fixing the welding machine on the free end of the lower casing pipe, while the welding machine is mounted on the casing pipe by means of a two-segment annular lower girth in such a way as to ensure that rotating non-contact with the casing pipe above this girth is coaxially installed la grain single-segment orbital module of the welding machine at least a full turn around the lower girth at a distance from the edge along the casing pipe, providing partial alignment at the edge of the filler wire and the radially supplied laser beam in the beam waist area during welding, then the upper casing pipe is lowered to contact with by the bottom end, the end of the upper casing pipe is grasped and fixed with a two-segment upper girth, coaxial with the lower one and rigidly fastened to it by a steel arcuate power structure, which is located outside and outside the orbital module to prevent its rotation from being limited and ensure its alignment with the grips, then winding the loop of the energy protective cable channel hanging on the side of the load-bearing structure on the drum of the said module for at least one full turn and in such an initial position with the wound cable channel, laser welding is carried out with the formation continuous weld in at least one pass, while in the process of full automatic reverse rotation of the orbital part of the welding machine, the cable channel is unwound from the drum, and at the end of the process of forming a continuous weld in at least one pass, the casing pipes are released from the girths of the welding apparatus, which is taken aside.

Note that this method is used to form a drill string from casing pipes for oil, gas, water wells or for the construction of bored supports of bridges, platforms and high-rise buildings.

EFFECT: improving the quality and strength characteristics of a monolithic drill string made of casing pipes butt-welded by orbital laser welding, moreover, sealed solid joints along the weld seam are more than 2 times higher in terms of torque than the permissible values for the traditional connection of casing pipes with a thread and a coupling, which leads to to an increase in the reliability of the formation and operation of a monolithic drill string, an increase in the speed and depth of drilling, which has a positive effect on the life and operating conditions of the casing string.

Brief description of the drawings

Fig. 1 is a general view of the welding machine, fixed at the outflow of the lower tube and holding coaxially the upper butt welded tube, with a local graphical section on the orbital module in the welding area.

Implementation of the invention

To form a drill string from casing steel pipes on a drilling platform, equipment is used to hold the pipes at the wellhead and supply new pipes to be installed. For installation by laser welding, a freely suspended upper casing pipe on a cable is brought to the joint of the retained lower casing pipe, at the outlet of which the laser welding machine (view 1, Fig. 1) is preliminarily fixed by means of the lower girth 2 of the free extension of the lower pipe 3. The lower girth 2 is rigid and coaxially fastened with the upper 4 arc-shaped body 5 of the supporting structure, the orbital module 6 is also mounted on it. orbital module, where the laser head with the filler wire feed mechanism 8 is installed.

Optical adjustment of the laser beam is carried out from the exit of the laser head to the edge of the lower casing pipe in two stages: first, “roughly” into the welding area within ±40 mm from the edge edge, when installing and fixing the lower girth, and then “finely”, by automatically shifting laser head along the tube inside the orbital single-segment module according to the position sensor. Next, the upper pipe 9, suspended on a cable, is brought coaxially to the joint of the lower one, aligning the edges of the ends and clamping it with the upper girth 4. Fine tuning to the edge can be carried out both before lowering the upper pipe 9, and after fixing it with the upper girth 4.

On the body 5, hydraulic drives of the girths are mounted - manipulators 10 and 11, lower and upper girths, respectively, driven by a hydraulic compressor 12. In the upper part of the body 5, a winch 13 (hoist) is mounted, which is suspended through a cable 14 to the crane of the drilling platform and allows install in the welding area and then remove the welding machine 1.

In the initial position, after fixing the joint of the casing pipes with girths 2 and 4, the orbital module 6 is in the position, as shown in Fig. 1, with a drum 16 free from the protective cable channel 15 for winding it when turning in the direction of the arrow 17. In this initial state of the drum, on the rear wall of the housing 5 of the supporting structure 5, the cable channel forms a loop 18 between the rollers 19-21 with a tightening mechanism (inside housing 5) tension of roller 19 as it moves in direction 22 (during rotation of drum 16) and during fixation of input part 23 on housing 5. As cable channel 15 is wound onto drum 16, loop 18 decreases and the orbital accelerated rotation of at least one revolution, comes to its original position - the start of welding without much loss of time, in a few seconds.

The cable channel 15 is fixed movably on the body of the supporting structure 5 and part of it in the form of a loop 18 hanging on the body for winding onto the drum 16 is pulled on its rear wall with adjustable tension that prevents the cable from sagging during winding (or during reverse motion) on the drum 16 of the orbital module 6.

On the body 5 of the supporting structure, a hydraulic compressor 12, a cable-channel tensioning mechanism 18, an electric drive of the orbital module, two hydraulic drives 10-11 are mounted to actuate the pipe wraps from the hydraulic compressor, and for a smoother bringing of the welding machine 1 to the welding site on the pipe, in addition to its pre-suspension on the cable of the crane of the drilling rig, install the hoist 11 on the upper part of the body 5 of the supporting structure.

The use of orbital laser welding in the formation of a drill string from casing pipes improves the quality and strength characteristics of the drill string, and the sealed solid welded joint at the joint of the casing pipes allows a torque of more than 30 kNm, which is more than 2 times higher than the permissible values for casing pipes in terms of torque with a traditional connection of joints with a thread and a coupling, does not require additional sealing of the joint. For example, for a casing pipe 114 mm with a wall thickness of 7.6 mm, steel strength group D. Premium high-strength threaded connection manufactured by TMK (TMK UP ™ PF (TMK UP ™ PF, URL: https://www.tmkup.ru/ru /connections/pf) - this is the official website of TMK) can withstand a torque of no more than 13 kNm. The same casing, welded by the method proposed in the invention, withstood a torque of 35 kNm and was not damaged. A larger torsional moment could not be created due to slippage of the cams of the test rig. At the same time, the weld was far from ideal and was specially selected according to the lower quality criterion. This type of thread TMK is the most durable in terms of make-up. For a pipe 114 × 7.36 with a strength group of N80, the maximum make-up torque is 12.9 kNm. We have obtained more than 35 kNm for such a pipe when forming a monolithic column according to the method of the present invention. TMK guarantees a limiting moment of 20.7 kNm for pipes made of steel of the transcendent strength group TMK 150!

The formation of the drill string according to the proposed method makes it possible to withstand extreme shock loads comparable to monolithic metal during the construction of bored supports, which is especially important in the construction of bridges, platforms and high-rise buildings. All this leads to an increase in the reliability of the formation and operation of a monolithic drill string, an increase in the speed and depth of drilling, and a positive effect on the life and operating conditions of the casing string.

Claims (1)

A method for forming a monolithic drill string by connecting pipes in the drill string by orbital laser welding, namely, by making mechanical contact at the end of the welded pipes by axial alignment, in which the lower pipe is fixed with a wellhead girth in the borehole, leaving a free end, and the upper pipe is brought to lower pipe from above for laser welding, characterized in that the drill string is formed from casing pipes with the possibility of attaching a drill-bit at its lower end, the upper casing pipe is brought to the lower casing pipe freely suspended from above, preliminary installation and fixation of the welding machine on the free at the end of the lower casing pipe, while the welding machine is mounted on the casing pipe by means of a two-segment annular lower girth in such a way as to provide a single-segment laser orbital module rotating coaxially with the casing above this girth of the lower casing at a distance from the edge along the casing pipe, which ensures partial alignment of the filler wire and the radially supplied laser beam in the beam waist area during welding at the edge, then the upper casing pipe is lowered until it contacts the end of the lower one, girth and fixation of the end of the upper casing pipe with a two-segment upper girth, coaxial with the lower one and rigidly fastened to it by a steel arcuate power structure, which is located outside and outside the orbital module to prevent restriction of its rotation and ensure its alignment with the grips, then the winding is carried out hanging on the side in the body of the load-bearing structure of the loop of the energy protective cable channel onto the drum of the mentioned module for at least one full turn and in such an initial position with the wound cable channel, laser welding is carried out with the formation of a continuous weld in at least one passage, while in the process of full automatic reverse rotation of the orbital part of the welding machine, the cable channel is unwound from the drum, and at the end of the process of forming a continuous weld, at least in one pass, the casing pipes are released from the girths of the welding machine, which is taken aside.

Images