KR101065028B1 - Riser tensioner having an emergency seal - Google Patents

Abstract

The present invention relates to a riser tensioning device having an emergency seal. A riser tensioning device having a plurality of cylinders located below the drilling line for tensioning the risers used for drilling of seabed resources, in which oil is supplied into the cylinders, a portion of which is inserted into the cylinders to reciprocate in the cylinders. Moving piston rod; A piston seal installed between the head of the piston rod and the wall of the cylinder for fluid sealing; Leak detection means for detecting leakage of oil through the piston seal; An emergency seal positioned above the head of the piston rod and operated to press toward the wall of the cylinder when oil leakage by the leak detection means is detected; Characterized in that it comprises a.
According to this configuration, the riser tensioning device is provided with a leak detection means for detecting the leakage of oil through the piston seal, and an emergency seal which is pressurized toward the wall of the cylinder to function as a fluid seal when the oil leaks, so that the piston seal is In the event of wear and leakage of oil, it is possible to prevent the oil from leaking to the upper part of the cylinder instead of the function of the piston seal.

Description

Riser tensioner having an emergency seal

The present invention relates to a riser tensioning device having an emergency seal. More particularly, the present invention relates to a riser tensioning device having an emergency seal for tensioning a riser extending from the drilling vessel for drilling of the seabed resources to the seabed.

As the international rapid industrialization and industry develop, the use of global resources such as petroleum is gradually increasing, so that stable production and supply of oil is becoming a very important problem at the global level.

For this reason, the development of marginal fields and deep-field oil fields, which have been neglected in recent years due to lack of economic feasibility, has become economic. Therefore, along with the development of seabed mining technology, a drilling vessel equipped with drilling equipment suitable for the development of such an oil field has been developed.

Conventional subsea drilling is mainly used for rig ship or fixed platform dedicated to subsea drilling, which can be sailed only by other tugboats and anchored at one point of the sea using mooring devices. In recent years, so-called drillships, which are manufactured in the same form as general ships so that they can be sailed by their own power and equipped with advanced drilling equipment, have been developed and used for underwater drilling.

In the center of a rig ship or drillship (hereinafter referred to as a drilling ship) equipped with various drilling equipments for drilling oil or gas existing in the basement of the seabed, a riser for drilling oil or gas existing in the basement of the seabed Alternatively, a moonpool is formed so that a drill pipe can be moved up and down.

1 is a side view showing a conventional drilling vessel performing drilling operation at sea level.

The operator advances the riser 4 and the drill pipe 5 downward through the door pool 3 formed in the center of the drilling line to place a well located on the rock 12 below the sea bed 6. Drill undersea resources stored in 13).

The riser 4 provides a passage through which the mud returns as a member that is advanced to the bottom of the sea floor 6 before advancing the drill pipe 5 to the well 13. When the riser 4 is installed, the drill pipe 5 is advanced downwardly to the well 13 through the seabed layer 11 into the riser 4.

As described above, when the riser 4 is advanced downward to the sea bottom 6 or when the drill pipe 5 is advanced to the oil well 13, the riser 4 or the drill pipe 5 which is connected to the long side is advanced downward. Rather, the short riser 4 or the drill pipe 5 are connected to each other and advanced downward. The blowout preventer (BOP) 7 is installed in the sea bottom 6 to prevent abnormal high pressure from rising up the drill pipe 5. In the subsea layer 11, the casing 8 is fixed by cement, and then the seabed resources are drilled by inserting the drill pipe 5 equipped with the drill bit 10 into the casing. The mud 9 is inserted into the drill pipe 5 to prevent the drill bit 10 from overheating by the heat generated when the drill bit 10 drills the ground and to lubricate to make drilling easier. do. This mud exits through the drill bit 10 and back through the casing 8 and riser 4. When the drilling operation is finished, the drill pipe 5 is transported to the drill floor through the door pool 3, dismantled and then transported to the loading site.

FIG. 2 is an enlarged view of a portion “A” of FIG. 1.

The risers 4a, 4b and 4 may be divided into an upper riser 4a and a lower riser 4b based on the slip joint 20. The riser 4 is connected from the drilling line to the bottom of the seabed, but in order to prevent the vibration of the upper riser 4a connected to the drilling line by the waves from being transmitted directly to the lower riser 4b, a slip joint 20 is placed in the middle. The relative vertical movement between the upper riser 4a and the lower riser 4b is made possible.

The riser 4 is connected to the bottom of the sea by thousands of meters, and the mud passes through the inside of the riser, so that the weight of the riser 4 itself and the mud and the bottom of the bottom are installed in the blowout prevention stack (BOP). If you add the weight of the car, the weight reaches thousands of tons.

When the drilling line is moved by waves and the force generated by the movement of the upper riser 4a connected to the drilling line is transmitted to the lower riser 4b as it is, buckling may occur at the riser 4 up to several thousand meters. . To prevent this, a riser tensioning device is installed which is connected to the slip joint 20 and the drilling line. The riser tensioning device tensions the lower riser 4b with a constant tensile force, thereby minimizing the effect of the movement of the drilling line by the waves on the riser 4.

The riser tensioning device is largely divided into a support ring 30, a cylinder device 40, and a hydraulic device 50.

The support ring 30 serves to connect the slip joint 20 and the cylinder device 40. The cylinder device 40 includes a cylinder 41 connected to a drilling line and a piston rod 42 connected to a support ring 30. A plurality of cylinder devices 40 are installed along the circumference of the riser 4. The hydraulic pressure is supplied into the cylinder 41 by the hydraulic device 50, and as the piston rod 42 rises, the lower riser 4b connected to the slip joint 20 is tensioned.

The hydraulic device 50 includes an accumulator 51 and a pneumatic container 52. When air is supplied to the accumulator 51 by the pneumatic container 52, the oil under the accumulator 51 is supplied into the cylinder 41 by the pressure to raise the piston rod 42.

Even when the distance between the cylinder 41 and the piston rod 42 changes as the drilling line moves vertically by the waves, the hydraulic device 50 can pull the lower riser 4b with a constant tensile force. The hydraulic pressure supplied to 41 is regulated constantly.

3 is a schematic cross-sectional view showing a cylinder internal structure of a conventional riser tensioning device.

A piston seal 43 is provided between the cylinder 41 and the head portion 42a of the piston rod 42 so that oil supplied to the lower portion b of the cylinder 41 by the hydraulic device is discharged from the cylinder 41. Provides hydraulic pressure to tension the piston rod 42 while preventing leakage to the upper portion a.

Since the drilling operation is performed for a long time at sea, when the piston seal 43 is worn by the reciprocating motion of the piston rod 42, oil may leak. The leaked oil accumulates in the upper portion a of the cylinder 41 above the head portion 42a of the piston rod 42. Over time, the amount of oil leaked increases, and if the stroke of the piston rod 42 is prolonged by high waves, it accumulates in the upper portion a of the cylinder 41 at the moment when the piston rod 42 is raised upward. The oil that has been inversely acts as a force for compressing the piston rod 42 may cause the piston rod 42 to bend.

Since the riser tensioning device is installed at the lower part of the drilling line, it is very difficult to detect the leakage of oil at all times, and when the oil leaks, the cylinder 41 installed at the lower part of the drilling line has to be dismantled for repair. There is a problem that takes a long time to repair. In addition, if a large amount of oil leaks and the riser tensioning device is not properly operated, a large accident such as buckling may occur in the riser.

Therefore, when oil leaks to the upper portion a of the cylinder 41 by the wear of the piston seal 43, a means for detecting it is required.

In addition, when the piston seal 43 is worn and oil leaks to the upper portion a of the cylinder 41, a means is required to replace the damaged piston seal 43 without dismantling the cylinder 41.

Accordingly, the present invention has been invented in view of the above circumstances, and in the riser tensioning device, when the piston seal installed between the cylinder and the piston rod is worn out and oil leaks, a means for detecting it and a damaged piston seal are replaced. It is an object to provide a riser tensioning device having an emergency seal that can be made.

According to an aspect of the present invention for achieving the above object, a riser tensioning device having a plurality of cylinders located in the lower portion of the drilling ship for tensioning the riser used for drilling of seabed resources, oil is supplied into the cylinder A piston rod, a portion of which is inserted into the cylinder, reciprocating in the cylinder; A piston seal installed between the head of the piston rod and the wall of the cylinder for fluid sealing; Leak detection means for detecting leakage of oil through the piston seal; An emergency seal positioned above the head of the piston rod and operated to press toward the wall of the cylinder when oil leakage by the leak detecting means is detected; Characterized in that it comprises a.

In addition, the emergency seal is characterized in that attached to the upper head portion of the piston rod by a fastening means.

In addition, the emergency seal is characterized in that it is guided and operated by a seal guide attached to the upper portion of the head of the piston rod by a fastening means.

According to another aspect of the present invention for achieving the above object, a riser tensioning device having a plurality of cylinders located in the lower portion of the drilling vessel for tensioning the riser used for drilling of seabed resources, oil is supplied into the cylinder A piston rod, a portion of which is inserted into the cylinder, reciprocating in the cylinder; A piston seal installed between the head of the piston rod and the wall of the cylinder for fluid sealing; Leak detection means for detecting leakage of oil through the piston seal; An emergency seal which is operated to protrude outside the head of the piston rod when the oil leakage by the leak detection means is detected and fluid seals between the cylinder and the piston rod; Characterized in that it comprises a.

In addition, a groove is formed on the surface of the head of the piston rod, the emergency seal is characterized in that it is pressed by the hydraulic pressure protrudes out of the head of the piston rod through the groove.

In addition, an actuator for pressing and operating the emergency seal; It characterized in that it further comprises.

In addition, the actuator includes a flow passage connected to the emergency seal through the interior of the piston rod, and an oil valve for supplying oil into the flow passage, when the oil leakage by the leak detection means is detected, the oil valve is It is characterized in that the hydraulic pressure is transmitted to the emergency seal through the passage.

In addition, a collection flow path is formed in the piston rod to allow the leaked oil to pass therethrough, and the riser tensioning device includes: a collection tank positioned at an end of the piston rod and connected to the collection flow path; It further comprises, The leak detection means is characterized in that by detecting the amount of oil collected in the collection tank to determine whether the oil leaks.

According to the present invention, the riser tensioning device has a leak detection means for detecting the leakage of oil through the piston seal, and when the oil leaks, it protrudes out of the head of the piston rod or is pressed toward the wall of the cylinder to function as a fluid seal. By providing the emergency seal, it is possible to prevent the oil from leaking to the upper portion of the cylinder in place of the function of the piston seal in the situation where the piston seal is worn out and the oil leaks.

1 is a side view showing a conventional drilling ship performing drilling operation at sea level.
FIG. 2 is an enlarged view of a portion “A” of FIG. 1.
3 is a schematic cross-sectional view showing a cylinder internal structure of a conventional riser tensioning device.
4 illustrates a riser tensioning device in accordance with one embodiment of the present invention.
5 is a view showing a state where the emergency seal protrudes out of the head of the piston rod in the riser tensioning device of FIG.
Figure 6 is a view showing the leak detection means of the riser tensioning device according to another embodiment of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. Here, in adding reference numerals to the elements of each drawing, it should be noted that the same elements are denoted by the same reference numerals as much as possible even if they are shown in different drawings.

4 illustrates a riser tensioning device in accordance with one embodiment of the present invention. 5 is a view showing a state in which the emergency seal protrudes out of the head of the piston rod in the riser tensioning device of FIG. Figure 6 is a view showing the leak detection means of the riser tensioning device according to another embodiment of the present invention.

The riser tensioning device is a device for tensioning the riser in connection with the drilling ship to prevent the movement of the drilling ship caused by waves in the drilling ship used for drilling of the seabed resources to the riser. Here, the drilling ship is meant to include all floating offshore structures for drilling of subsea resources such as drillships, rig ships, semi-submersible drilling rig, tension leg platform.

Riser tensioning device 100 of the present invention is configured to tension the riser by the piston rod 120 is tensioned by the hydraulic pressure supplied in the cylinder 110 as in the prior art. Since the operation of the fluid in the cylinder 110 of the riser tensioning device 100 is the same or similar to the prior art, a detailed description thereof will be omitted.

Riser tensioning device 100 of the present invention includes a cylinder 110, piston rod 120, piston seal 130, leak detection means, emergency seal 150, oil valve 170 and the like.

Oil flows into the cylinder 110 to generate hydraulic pressure that raises the piston rod 120 in the direction of the arrow.

A portion of the piston rod 120 is inserted into the cylinder 110, and reciprocates in the cylinder 110 by the movement of the drilling line according to the wave or the hydraulic pressure in the cylinder 110. The piston rod 120 is formed in a T-shape, and has a head portion 120a thereon.

A piston seal 130 for fluid sealing is installed between the head portion 120a of the piston rod 120 and the wall surface of the cylinder 110, thereby restricting the flow of oil introduced into the cylinder 110. Allow hydraulic pressure to be generated within.

Since the drilling operation is performed for a long time at sea, when the piston seal 130 is worn by the continuous reciprocating motion of the piston rod 120, oil may leak through the piston seal 130. The leaked oil accumulates in the upper portion of the cylinder 110 above the head portion 120a of the piston rod 120. Over time, the amount of leaked oil increases, and this leaked oil acts as a force that compresses the piston rod 120 inversely the moment the piston rod 120 rises upward, thus adversely affecting the reciprocating motion of the piston rod. Can have

Therefore, the present invention includes a leak detection means for detecting the oil leaked to the upper portion of the cylinder 110, an emergency seal (150) for replacing the worn piston seal 130 and the like.

The leak detection means may be configured as a controller for determining whether the oil leaks by calculating a difference between the amount of oil introduced into the cylinder 110 and the amount of oil actually remaining in the cylinder 110. The amount of oil introduced into the cylinder 110 is a value obtained by subtracting the amount of oil remaining in an apparatus other than the cylinder 110, such as the accumulator 51 (see FIG. 2), from the total amount of oil introduced. The amount of oil actually remaining in the cylinder 110 is the amount of oil measured by a load sensor or the like installed in the cylinder 110. Considering that a small amount of oil may leak through the piston seal 130, it is determined that the oil has leaked when the amount of the leaked oil is a predetermined amount or more.

On the other hand, the leak detection means is the oil that is leaked through the collection flow path 180 formed in the piston rod 120 is collected in the collection tank 190 through the connection flow path 181, the oil of the collected in the collection tank 190 The amount can be detected to determine whether the oil is leaking. Collection tank 190 may be located at any suitable location. The collection tank 190 may be attached with a sensor 195 for detecting the amount of leaked oil (see FIG. 6). If oil leakage can be detected, the leak detection means can be implemented in various forms by those skilled in the art.

When oil leakage is detected by the leak detection means, the actuator presses the emergency seal 150 to protrude the emergency seal out of the head portion 120a of the piston rod 120.

The actuator can be implemented in various forms. For example, the actuator may include a flow path 160 connected to the emergency seal 150 through the interior of the piston rod 120 and an oil valve 170 for supplying oil into the flow path 160.

When the oil leak is detected, the leak detection means outputs an oil leak signal to the controller (not shown), and the controller opens the oil valve 170. The oil valve 170 is connected to the oil-operated pump 171 connected to the HPU. When the oil valve 170 is opened, oil is supplied from the oil-operated pump 171 to supply hydraulic pressure along the oil passage 160 to the emergency seal ( Up to 150).

On the surface of the head portion 120a of the piston rod 120, a ring-shaped groove 121 is formed along the outer circumference of the head portion 120a, and the emergency seal 150 normally has the head portion of the piston rod 120 ( The pressure is maintained toward the groove 121 inside the 120a). In one embodiment, the emergency seal 150 has a rounded front end portion 150a, so that the front end portion 150a can maintain its state when the front end portion 150a protrudes out of the head portion 120a of the piston rod 120. It may be made of a rear end 150b for supporting. The shape and structure of the emergency seal 150 may be implemented by those skilled in the art in various forms.

When the leakage of oil is detected and the hydraulic pressure is delivered to the emergency seal 150, as shown in FIG. 5, the emergency seal 150 is pressurized to protrude out of the groove 121. At this time, the rear end portion 150b of the emergency seal 150 is supported by contacting the inner wall of the head portion 120a of the piston rod 120, thereby achieving fluid sealing while maintaining the state where the emergency seal 150 protrudes. Make sure

7 illustrates a riser tensioning device in accordance with another embodiment of the present invention. FIG. 8 is a view illustrating a state in which an emergency seal is operated by detecting leakage of oil in the riser tensioning device of FIG. 7.

In the riser tensioning device 200 of the present embodiment, the emergency seal 250 is guided by a seal guide 251 attached to the head portion 220a of the piston rod 220 by a fastening member 252 such as a bolt. It works. Alternatively, the emergency seal 250 may be attached and operated on the head portion 220a of the piston rod 220 by a fastening member 252 such as a bolt without guidance by the seal guide 251.

When the piston seal 230 is worn out and oil leaks and the leak is detected by the leak detection means, the actuator presses the emergency seal 250 toward the wall surface of the cylinder 210, so that the emergency seal 250 is formed of the auxiliary seal. In charge of function. The leak detection means has substantially the same configuration as the leak detection means described with reference to FIGS. 4 and 5.

As in the embodiment shown in FIG. 4, the actuator includes a flow path 260 connected to the emergency seal 250 through the interior of the piston rod 220, and an oil valve 270 for supplying oil into the flow path 260. It may include.

When the oil leak is detected, the leak detection means outputs an oil leak signal to the control unit (not shown), and the control unit opens the oil valve 270. The oil valve 270 is connected to the oil operated pump 271 connected to the HPU, so that when the oil valve 270 is opened, oil is supplied from the oil operated pump 271 so that the hydraulic pressure along the flow path 260 may be used. Up to 250). This hydraulic pressure presses the emergency seal 250 into close contact with the wall surface of the cylinder 210, so that the emergency seal 250 can function as an auxiliary seal.

In this embodiment, the emergency seal 250 is attached to the head portion 220a of the piston rod 220, so that the installation and maintenance is easy, even in the event of a failure in the emergency seal 250 can be easily replaced. have.

As described above, the riser tensioning device of the present invention is a leak detection means for detecting the leakage of oil through the piston seal, and when the oil leaks protrudes out of the head of the piston rod or pressurized to the wall of the cylinder fluid sealing By providing an emergency seal functioning as a function, it is possible to prevent the oil from leaking to the upper portion of the cylinder, so that the piston seal may be worn to sufficiently cope with an emergency situation in which the oil leaks.

In general, the riser tensioning device is installed in the lower portion of the drilling vessel, difficult to access humans, and takes a lot of time to repair, the riser tensioning device having the leak detection means and the emergency seal of the present invention is a safety means in an emergency You will be faithful in your role.

In the riser tensioning apparatus of the present invention, it will be apparent to those skilled in the art that the leak detection means, the emergency seal and the actuator can be implemented in various forms as long as the respective functions can be achieved.

It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit and scope of the invention will be.

100: riser tensioning device
110: cylinder
120: piston rod
120a: head portion
121: home
130: piston seal
150: emergency seal
150a: shear
150b: rear end
160: Euro
170: oil valve
171: Oil Operated Pump

Claims (8)

In the riser tensioning device having a plurality of cylinders located in the lower portion of the drilling vessel for tensioning the riser used for drilling of the seabed resources, the oil is supplied into the cylinder,
A piston rod, part of which is inserted into the cylinder, for reciprocating in the cylinder;
A piston seal installed between the head of the piston rod and the wall of the cylinder for fluid sealing;
Leak detection means for detecting leakage of oil through the piston seal;
Located in the groove formed in the upper portion of the head of the piston rod, when oil leakage by the leak detection means is detected, it is pressed toward the wall surface of the cylinder protrudes out of the head portion of the piston rod to the wall surface of the cylinder Emergency seal to prevent leakage of oil through;
Riser tensioning device comprising a. The method according to claim 1,
And the emergency seal is attached to the upper portion of the head of the piston rod by a fastening means. The method according to claim 1,
And the emergency seal is guided and operated by a seal guide attached to an upper portion of the head of the piston rod by a fastening means. In the riser tensioning device having a plurality of cylinders located in the lower portion of the drilling vessel for tensioning the riser used for drilling of the seabed resources, the oil is supplied into the cylinder,
A piston rod, part of which is inserted into the cylinder, for reciprocating in the cylinder;
A piston seal installed between the head of the piston rod and the wall of the cylinder for fluid sealing;
Leak detection means for detecting leakage of oil through the piston seal;
An emergency seal positioned inside the head of the piston rod and operated to protrude out of the head of the piston rod when oil leakage by the leak detection means is detected, for sealing fluid between the cylinder and the piston rod;
Riser tensioning device comprising a. The method according to claim 4,
A groove is formed on the surface of the head of the piston rod,
And the emergency seal is pressurized by hydraulic pressure to project out of the head portion of the piston rod through the groove. The method according to any one of claims 1 to 5,
An actuator configured to pressurize the emergency seal;
Riser tensioning device, characterized in that it further comprises. The method of claim 6,
The actuator includes a flow passage connected to the emergency seal through the inside of the piston rod, and an oil valve for supplying oil into the flow passage,
And when the oil leak is detected by the leak detection means, the oil valve is opened so that hydraulic pressure is transferred to the emergency seal through the flow path. The method according to any one of claims 1 to 5,
A collection flow path is formed in the piston rod to allow the leaked oil to pass therethrough,
The riser tensioning device includes a collection tank connected to the collection flow path of the piston rod; Further comprising:
And the leak detection means detects the amount of oil gathered in the collection tank to determine whether the oil leaks.

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