KR101665478B1 - Drilling system and method - Google Patents

Abstract

A drilling system for drilling underwater resources is disclosed.
The drilling system of the present invention comprises a drilling structure installed in an offshore structure for drilling; And a drill pipe support unit provided at the seabed and connected to the drilling structure for supporting the weight of the drill pipe to be drilled.

Description

[0001] DRILLING SYSTEM AND METHOD [0002]

The present invention relates to a drilling system and method, and more particularly, to a drilling system and method capable of performing a drilling operation while supporting the load of a drill pipe at the sea floor.

With the rapid development of international industrialization and industry, the use of earth resources such as oil is gradually increasing, and thus the stable production and supply of crude oil is becoming an increasingly important issue globally.

For this reason, recently marginal field or deep-sea oil development has been economically feasible, which has been neglected due to economic difficulties so far. Therefore, with the development of submarine mining technology, drilling facilities suitable for the development of such oilfields A drill ship having a plurality of drill holes has been developed.

Conventional submarine drilling has been mainly used for a rig ship or a fixed platform for underwater drilling which can be sailed only by other tugboats and which is used for drilling underwater at anchor point on the sea using a mooring device.

Drill ships and semi-submersible rigs, which are manufactured in the same form as general vessels, have been developed to mount sophisticated drilling rigs and to navigate with their own power, It is used in production.

And recently, oil and gas have been found in deep-water, requiring drilling at depths of over 3,000 meters.

The drilling work in the deep sea has the following problems.

The first is the handling problem of the drill pipe. As the depth of the drill pipe increases, the length of the drill pipe becomes longer and the breakage due to torsion or buckling may become frequent.

Since the length of the drill pipe is increased, the contact with the casing may be frequently caused by the distortion due to the twisting or buckling.

The second problem is the top drive. The top drive is used in place of a rotary table as a means of delivering rotational motion to a drill string.

The top drive is suspended from a traveling block, driven by an electric or hydraulic motor, and the drill string is directly connected to the top drive.

As described above, since the length of the drill pipe increases toward the deep sea, the increase in the weight of the drill string is expected to increase the down-time of the top drive.

In particular, the travel block is a very large and diverse sheave lifting block that basically supports the weight of the drill string during drilling.

The travel block is also used to move the drill pipe and casing into and out of the drilling hole by up and down movements by drawworks.

As the depth of the drill string increases toward the deep sea, the size of the travel block must be increased to support the load of the drill string, which increases the size of the heave compensator.

Further, since the weight of the drill string is increased, there is a disadvantage that the energy generated due to the falling load braking can not be absorbed quickly during the lowering of the dowel work, and the moment of the main AC power source Instantaneous transients may occur due to a power outage.

In addition, since a plurality of high-load drilling equipments are arranged in the upper area of the main deck, the center of gravity of the hull becomes higher. As a result, when the ship is tilted sideways by the external force, the stability of the ship, which is the property of returning to the original state, is also degraded, which may adversely affect the stability of the drill ship. Good stability and stable operation can be achieved without overturning in severe winds and waves.

Therefore, a new improvement is needed which can overcome the above-mentioned disadvantages caused by supporting the load of the drill string in the upper region of the main deck.

International Patent Publication No. WO2004-018826 (seabed rig as) 2004.03.04

SUMMARY OF THE INVENTION Accordingly, it is an object of the present invention to provide a drilling system capable of supporting a load of a drill pipe on a seabed so as to remove a heavy load drilling equipment disposed in an upper area of a main deck.

According to an aspect of the present invention, there is provided a drilling system for drilling a submarine resource, the drilling system comprising: a drilling structure installed in an offshore structure for drilling; And a drill pipe support unit provided at the seabed and connected to the drilling structure for supporting the weight of the drill pipe to be drilled.

The drill pipe support unit includes: a main body fixed to a seabed and provided with an internal space in which the inflow of seawater is blocked; A drill pipe holding part provided on the main body and holding the drill pipe and rotated together with the drill pipe; And a drill pipe load supporting portion provided on the main body and rotatably supporting the drill pipe holding portion.

The drill pipe holding portion includes: a holding body rotatably supported by the load supporting portion of the drill pipe; And a plurality of holding cylinders provided on the holding body and holding the drill pipe passing through the holding body.

The holding body may be supported by a plurality of guide rods provided inside the body when rotating, such as the drill pipe held by the plurality of holding cylinders.

The drill pipe load supporting portion includes: a support frame rotatably supporting the drill pipe holding portion; And a plurality of load supporting cylinders provided inside the main body to support the support frame in a movable manner.

The drilling system may further include a mud return unit connected to a blowout preventer (BOP) provided at the seabed and returning a mud without a riser pipe.

The mud return unit includes a mud storage tank connected to the BOP and storing a mud returned from the drilling hole; And a mud return pump provided in the mud storage tank for pumping the stored mud to the drilling structure.

The drilling system may further include a drill pipe rotating part provided inside the body for rotating the drill pipe held by the drill pipe holding part.

The drill pipe rotating portion includes: a driven gear provided on an outer circumferential surface of the drill pipe holding portion; And a driving motor which is supported by the drill pipe holding part and engaged with the driven gear to rotate the drill pipe holding part holding the drill pipe.

The drill pipe rotating part may further include a lifting guider provided inside the main body and guiding the lifting and lowering of the driving motor.

The drilling system may further comprise a drill string handling unit for handling the drill string when connecting or disconnecting the drill pipe.

The drill string handling unit comprising: a clamp for clamping the drill string; And a clamp lifting unit provided on the drilling structure for lifting the clamp.

The clamp lifting unit includes: a drawrow installed on a drill floor of the drilling structure to lift and lower the clamp and connected to the clamp through a derrick; And a plurality of rollers provided on the derrick to support a connecting member connecting the drawrows and the clamp.

The drilling system may include: a rotating shaft rotatably installed inside the body; A connecting member connecting the rotating shaft and the drill pipe to rotate the drill pipe; And a drill pipe rotation unit provided inside the main body and having a rotation axis drive motor for rotating the rotation.

According to another aspect of the present invention, there is also provided a method of manufacturing a drill pipe, comprising the steps of: fixing a drill pipe supporting unit for holding a drill pipe on a seabed; And rotating the drilling pipe connected to the drilling structure in a state where the drill pipe supporting unit supports the weight of the drill pipe at the seabed by rotating the drilling pipe.

Wherein the drilling method further comprises a mud returning step of returning the mud supplied to the drilling hole during the drilling operation and wherein the mud is returned by the mud return unit to the drilling structure without a riser pipe .

Embodiments of the present invention can remove the conventional top drive, traveling block, etc. by supporting the drill pipe with a drill pipe support unit at the bottom of the main deck rather than the upper area of the main deck, thereby simplifying the equipment of the drilling structure.

Also, since the drilling equipment with high load is removed in the upper area of the main deck, the center of gravity of the hull can be lowered and the stability of the drilling structure can be improved.

1 is a schematic view of a drilling system according to a first embodiment of the present invention.
Fig. 2 is a cross-sectional view schematically showing the drill pipe support unit shown in Fig. 1. Fig.
3 is a cross-sectional view taken along the line III-III in Fig.
FIG. 4 is a view schematically showing a process of a mud returned from a drilling hole in the present embodiment.
5 is an enlarged view of the "A" area in Fig.
6 is a modified embodiment of the drill pipe rotating part shown in Fig.
7 is a schematic view of a drill pipe and rotating equipment in a drilling system according to a second embodiment of the present invention.
8 is a schematic view of a drill pipe and rotating equipment in a drilling system according to a third embodiment of the present invention.

In order to fully understand the present invention, operational advantages of the present invention, and objects achieved by the practice of the present invention, reference should be made to the accompanying drawings and the accompanying drawings which illustrate preferred embodiments of the present invention.

Hereinafter, the present invention will be described in detail with reference to the preferred embodiments of the present invention with reference to the accompanying drawings. Like reference symbols in the drawings denote like elements.

FIG. 1 is a schematic view of a drilling system according to a first embodiment of the present invention, FIG. 2 is a sectional view schematically showing the drill pipe support unit shown in FIG. 1, and FIG. 3 is a cross- FIG. 4 is a view schematically showing the process of the mud returned from the drilling hole in this embodiment, and FIG. 5 is an enlarged view of the "A" region of FIG.

As shown in these drawings, the drilling system 1 according to the present embodiment includes a drilling structure 100, and a drill pipe (drill pipe) provided on the seabed and connected to the drilling structure 100 A drill pipe support unit 200 for supporting a load, a mud return unit 300 connected to a BOP (blowout preventer) provided on the sea bed to return a mud without a riser pipe, A drill pipe rotating part 400 provided inside the drill pipe holding part 220 for rotating the drill pipe DP held by the drill pipe holding part 220 and a drill pipe rotating part 400 for handling a drill string when connecting or disconnecting the drill pipe DP and a drill string handling unit 500 for handling the drill string.

The drilling structure 100 includes a drillship or a semi-submerged rig in which a drill pipe DP necessary for a drilling operation is loaded.

In the present embodiment, the drilling structure 100 is provided with a moonpool MP as a passage through which the drill pipe DP is moved to the seabed. A drill floor DF and a derrick D) are provided.

The present embodiment supports the load of the drill pipe DP on the underside of the main deck MD rather than the upper area of the main deck MD so that the top drive, traveling block, It is not necessary to install a heave compensator.

Therefore, the upper structure of the derrick D can be simplified, and the vertical center of gravity of the hull can be lowered, thereby improving the stability and improving the stability.

In addition, since the load of the drill pipe DP is supported at the seabed, the size and the capacity of the drawworks 521 used for raising and lowering the drill pipe DP can be reduced compared to the past.

The drill pipe support unit 200 is provided on the seabed as shown in Fig. 1 and supports loads such as a drill pipe DP at the seabed during drilling work, and functions as a conventional travel block .

Therefore, in this embodiment, it is not necessary to install the traveling block in the drilling structure 100, so that the time and cost required for installing the traveling block can be reduced.

2, the drill pipe support unit 200 includes a main body 210 fixed to a seabed and provided with an inner space for blocking the inflow of seawater, A drill pipe load holding part 230 provided in the main body 210 and rotatably supporting the drill pipe holding part 220 to rotate together with the drill pipe DP while holding the drill pipe holding part DP, .

The main body 210 of the drill pipe support unit 200 can be fixed to the seabed by a plurality of support legs 211 provided on the lower side. 2, the drill pipe DP is penetrated into the main body 210 so that the drill pipe DP and the main body 210 prevent the seawater from flowing into the main body 210, A sealing portion 212 is provided in the contact area.

In this embodiment, the sealing part 212 includes a housing (not shown) provided in a hole of the main body 210 through which the drill pipe DP passes, a bearing (not shown) rotatably coupled to the housing, And a sealing member (not shown) that rotates together with the bearing and seals the gap between the drill pipe DP and the main body 210.

The drill pipe holding portion 220 of the drill pipe support unit 200 holds the drill pipe DP to support the load of the drill pipe DP and is rotated as the drill pipe DP.

2, the drill pipe holding part 220 includes a holding body 221 rotatably supported on the drill pipe load supporting part 230, a holding body 221 provided on the holding body 221, And a plurality of holding cylinders 222 for holding a drill pipe DP passing through the pipe 221.

2, a hole through which the drill pipe DP passes is formed at the central portion of the holding main body 221 of the drill pipe holding portion 220. As shown in Fig. 3, a guide hole 221a through which a guide rod 213 provided in the main body 210 passes is continuously provided in a circular shape, and the holding main body 221 is rotatably supported by a guide rod 221, (213).

The plurality of holding cylinders 222 of the drill pipe holding part 220 are provided inside the holding body 221 to press and hold the drill pipe DP as shown in FIG.

The plurality of holding cylinders 222 are provided inside the holding body 221 and rotate together with the holding body 221 so that when the holding cylinder 222 is operated with hydraulic pressure, The hydraulic line connected to the cylinder 222 may be twisted, and a separate device must be installed to prevent such twisting.

Therefore, in this embodiment, the plurality of holding cylinders 222 may be electromechanical operated cylinders, and power supply to the electric cylinders may be supplied by a large capacity battery (not shown) provided on the upper portion of the holding body 221 . In this case, since the large-capacity battery also rotates together with the holding body 221, there is no problem of twisting the electric wire.

The drill pipe load supporting portion 230 of the drill pipe support unit 200 supports the drill pipe holding portion 220 holding the drill pipe DP to control the load applied to the drill bit during drilling.

2, the drill pipe load supporting portion 230 includes a support frame 231 for rotatably supporting the holding main body 221, a plurality of load supporting members 231 for supporting the support frame 231, And a support cylinder 232.

2, a support bearing 231a is provided between the support frame 231 of the drill pipe load supporting portion 230 and the holding main body 221, and the support bearing 231a is fixed to the holding main body 221 221 are freely rotated without being restrained by the support frame 231.

A plurality of load supporting cylinders 232 of the drill pipe load supporting portion 230 are provided inside the main body 210 to support the support frame 231 as shown in FIG.

In this embodiment, the plurality of load-supporting cylinders 232 can be lowered at a speed corresponding to the drilling speed of the drill pipe DP.

As shown in FIG. 1, the mud return unit 300 serves to return the mud returned from the drilling hole to the drilling structure 100 without a riser pipe, which is connected to a blowout preventer (BOP).

The present embodiment rotates the drill pipe DP at the bottom of the main deck MD rather than the upper area of the main deck MD so that if the riser pipe surrounds the outside of the drill pipe DP, DP, or it may be difficult to rotate the drill pipe DP.

Therefore, when the mud is returned without the riser pipe as in the present embodiment, the load of the drill pipe DP can be smoothly supported or rotated.

1, the mud return unit 300 includes a mud storage tank 310 connected to the BOP and storing a mud returned from the drilling hole, a mud storage tank 310 provided in the mud storage tank 310, And a mud return pump 320 for pumping the stored mud to the drilling structure 100.

The riserless drilling system to which this embodiment is applied circulates the mud, the rock, and the like using a small-diameter pipe instead of the large-diameter riser pipe used in the conventional marine riser system.

This system keeps the pressure at the top of the wells equal to the hydrostatic pressure due to seawater. Various methods are available for this purpose, but a method may be used in which a pump is installed on the seabed so that the suction pressure of the pump is maintained at the same value as the hydrostatic pressure due to seawater.

Hereinafter, a processing procedure of the mud returned from the drilling hole will be briefly described with reference to FIG.

The mud supplied to the borehole is returned to the mud return unit 300 through a processing system as shown in FIG. 4 for reuse. That is, pieces of rock such as gravel or coarse stones contained in cutting cuts, including returned mud, are filtered in a gumbo box. The shale, clay, or rock fragments contained in cutting cuts that pass through the gumbo box are divided into separate shale shakers by a flow divider.

Mute cutting cuts through the flow divider are separated into mud, oil based mud and cutting, and water based mud and cutting through a water separator.

The mud separated from the water separator is supplied to the feed tank through the recycling system and then re-supplied to the drilling hole. The oil-based mud cutting cutting material is supplied to the cutting conveyor and stored in the container, And treated at sea via a centrifuge system.

The aqueous mud cutting cuts separated from the water separator are discharged to the sea via the cutting chute. The water separator is normally operated flexibly according to the operation and drilling conditions, and eight units are operated at maximum operation.

The drill pipe rotation unit 400 enables the drilling operation by rotating the drill pipe DP, and performs the function of a conventional top drive.

In this embodiment, the drill pipe rotation part 400 is provided inside the main body 210 and can rotate the drill pipe DP by rotating the drill pipe holding part 220, as shown in FIG.

2, the drill pipe rotating part 400 includes a driven gear 410 provided on the outer circumferential surface of the holding main body 221, a lifting support rod (not shown) provided inside the main body 210, A driving motor 430 which is provided on the upper portion of the main body 420 so as to be able to move up and down by the driven gear 410 and is engaged with the driven gear 410; And a lifting guider 440 for lifting and lowering the driving motor 430 at the time of lifting and lowering the driving motor 221.

The driven gear 410 of the drill pipe rotating part 400 may be continuously provided while surrounding the outer circumferential surface of the holding body 221 at 360 degrees as shown in FIG.

3, the driving motor 430 of the drill pipe rotating part 400 may be provided at an equal angle.

The lifting guider 440 of the drill pipe rotating part 400 is supported in a free state without being constrained by the upper surface of the holding main body 221 and the other side is fixedly connected to the driving motor 430, The lifting body 221 is lifted and lowered as shown in FIG.

Therefore, the driving motor 430, which is fixed to the elevating guider 440 at one side and is vertically supported by the elevating support rod 420, is elevated and lowered as the elevating guider 440 is lifted and lowered, (430).

The upper end of the drill pipe DP when rotating the drill pipe DP with the drill pipe rotation unit 400 in the present embodiment is connected to the rotary table RT provided in the drill floor DF of the drilling structure 100 As shown in Fig.

The drill string handling unit 500 may be used to support a pipe stand to connect pipe stands to each other during a drilling operation or in a tripping out operation to remove the entire drill string, And to raise the drill pipe (DP) to the drill floor (DF).

For reference, a pipe stand or a stand refers to a pre-assembled three drill pipes (DP) each having a length of 9 m, one pipe stand having a height of about 27 m, a lower part placed on a drill floor (DF) It is placed vertically in the fingerboard (FB).

Also in this embodiment the drill string comprises a drill pipe, a pipe stand, a drill bit or a drill collar.

This embodiment requires no new top drive or traveling block by supporting the load of the drill pipe DP at the underside thereof, and therefore, a new improvement measure for effectively handling the drill string in the drilling process is required. To solve this problem, A string handling unit 500 is provided.

 4, the drill string handling unit 500 includes a clamp 510 for clamping a drill string, a clamp elevating portion provided on the drilling structure 100 to elevate the clamp 510 520).

The clamp 510 of the drill string handling unit 500 can be operated by the built-in electric cylinder to clamp the drill string.

The clamp lifting unit 520 of the drill string handling unit 500 includes the drawrows 521 provided on the drill floor DF and the drawrows 521 provided on the derrick D, And a plurality of rollers 522 for supporting the wires connecting the clamps 510.

The present embodiment includes a stand building arm SB for lifting up a pipe stand assembled in the drill floor DF with a finger board FB and a pipe stand standing near the finger board FB, And a bridge crane (BC) that seats and stores the bridge crane (FB).

In the present embodiment, the stand building arm SB is provided with a function of clamping the stand pipe, and can be raised and lowered along a pair of rails R, which are long in the height direction of the derrick D.

In the present embodiment, the bridge crane BC can be moved in both the lateral direction and the longitudinal direction of the fingerboard FB and is movable in the longitudinal direction of the pair of guide rails GR, as shown in Fig. To a connection rod (CR) which is connected to the connecting rod (CR).

That is, in this embodiment, the bridge crane BC can be moved in the longitudinal direction of the connecting rod CR and in the longitudinal direction of the pair of guide rails GR. In this method, a gear and coupling structure of a rack and a pinion is provided at a connecting portion of the bridge crane BC and the connecting rod CR, and at a connecting portion of the connecting rod CR and the pair of guide rails GR, So that the pinion gear can be moved by the rotational force of the motor.

6 is a modified embodiment of the drill pipe rotating part shown in Fig.

In this embodiment, as shown in FIG. 6, a drill pipe rotation part 600 of a type different from that of the above-described embodiment is provided in the body 210 to rotate the drill pipe DP.

6, the drill pipe rotating unit 600 includes a rotating shaft 610 rotatably provided in the main body 210 and a rotating shaft 610 connected to the rotating shaft 610 and the drill pipe DP, A rotating shaft driving motor 630 provided inside the main body 210 and engaged with the rotating shaft 610 to rotate the rotating shaft 610; .

The rotating shaft 610 of the drill pipe rotating part 600 is fixed to a bearing provided on the inner bottom of the main body 210 and can be rotated. Also, although not shown, a guide rod 213 for rotatably supporting the rotary shaft 610 may be provided at the upper end of the rotary shaft 610.

The connecting member 620 of the drill pipe rotating part 600 may be a rope that is wound on the rotary shaft 610 at one side and connected to the drill pipe DP at the other side as shown in Fig. In this embodiment, the string as the connecting member 620 transmits the rotational force of the rotary shaft 610 to the drill pipe DP without slipping, and in order to prevent the string from slipping on the rotary shaft 610 itself, Likewise, it can be wound on most of the rotating shaft 610.

7 is a schematic view of a drill pipe and rotating equipment in a drilling system according to a second embodiment of the present invention.

The drilling system 1a according to the present embodiment is configured to deform the shape of the drill pipe DP into engagement with a part of the rotating equipment as shown in Fig. 7, and to rotate the drill pipe DP DP) can be drilled.

In this embodiment, the upper end and the lower end of the drill pipe DP may be provided so as to protrude to one side of the outer peripheral surface as shown in FIG. 7, and the rotary equipment may be a rotary table RT. Further, on the inner surface of the rotary table RT, a groove may be provided to receive a sharp projecting portion of the drill pipe DP.

In this embodiment, the rotary table RT is provided with a thread provided on the outer circumferential surface, a support table provided on the drill floor DF to the main deck MD and provided with threads for engaging the threads of the rotary table RT on the inner wall When the drill floor DF is lowered.

8 is a schematic view of a drill pipe and rotating equipment in a drilling system according to a third embodiment of the present invention.

The drilling system 1b according to the present embodiment may have a hexagonal shape in which the joint portion of the drill pipe DP is engaged with the rotating equipment, as shown in Fig. Therefore, when the rotating equipment is operated, the drilling pipe (DP) can be drilled down along the inside of the rotating equipment.

Meanwhile, in this embodiment, the drill pipe DP may mean one drill pipe, or may be a pipe stand in which three drill pipes are combined.

As described above, the present embodiment can remove the conventional top drive, traveling block, and the like by supporting the drill pipe with the drill pipe supporting unit at the bottom of the main deck rather than the upper area of the main deck, thereby simplifying the equipment of the drilling structure .

Also, since the drilling equipment with high load is removed in the upper area of the main deck, the center of gravity of the hull can be lowered and the stability of the drilling structure can be improved.

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 or scope of the invention. Accordingly, such modifications or variations are intended to fall within the scope of the appended claims.

1: Drilling system 100: Drilling structure
200: Drill pipe supporting unit 210: Body
220: Drill pipe holding part 230: Drill pipe load supporting part
300: Mud return unit 310: Mud storage tank
320: Mud return pump 400, 600: Drill pipe rotating part
410: driven gear 420: lifting / supporting rod
430: driving motor 440: lifting guider
500: Drill string handling unit 510: Clamp
520: clamp lifting part 610: rotating shaft
620: connecting member 630: rotating shaft driving motor
BC: Bridge crane CR: Connection load
D: Derrick DF: Drill Floor
DP: Drill pipe FB: Fingerboard
GR: Guide rail MD: Main deck
MP: Format R: Rail
RT: Rotary table SB: Stand building arm

Claims (16)

A drilling system for drilling underwater resources,
Drilling structures installed in offshore structures;
A drill pipe support unit provided at the seabed and connected to the drilling structure to support the weight of the drill pipe to be drilled; And
And a mud return unit connected to a BOP (blowout preventer) provided at the seabed and returning the mud without a riser pipe,
The drill pipe support unit includes:
A main body fixed to the seabed and provided with an internal space in which the inflow of seawater is blocked;
A drill pipe holding part provided on the main body and holding the drill pipe and rotated together with the drill pipe; And
And a drill pipe rotating part provided inside the body for rotating the drill pipe held by the drill pipe holding part,
Wherein the drilling structure does not include a top drive and the drill pipe is not rotated by the top drive. The method according to claim 1,
The drill pipe support unit includes:
Further comprising a drill pipe load supporting portion provided on the main body for rotatably supporting the drill pipe holding portion. The method according to claim 1,
The drill pipe holding portion
A holding body rotatably supported by the drill pipe load supporting portion; And
A plurality of holding cylinders provided on the holding body to hold the drill pipe passing through the holding body;
≪ / RTI > The method of claim 3,
Wherein the holding body is supported by a plurality of guide rods provided inside the main body when rotating as the drill pipe is held by the plurality of holding cylinders. The method of claim 2,
The drill pipe load supporting portion includes:
A support frame rotatably supporting the drill pipe holding part; And
A plurality of load supporting cylinders provided inside the main body and supporting the supporting frame so as to be able to move up and down;
≪ / RTI > delete The method according to claim 1,
The mud return unit includes:
A mud storage tank connected to the BOP and storing a mud returned from a drilling hole; And
A mud return pump provided in the mud storage tank for pumping the stored mud to the drilling structure;
≪ / RTI > delete The method according to claim 1,
The drill pipe rotation unit includes:
A driven gear provided on an outer circumferential surface of the drill pipe holding portion; And
A driving motor which is supported by the drill pipe holding part and engages with the driven gear to rotate the drill pipe holding part holding the drill pipe;
≪ / RTI > The method of claim 9,
The drill pipe rotation unit includes:
And a lifting guider provided inside the main body for guiding the lifting and lowering of the driving motor. The method according to claim 1,
Further comprising a drill string handling unit for handling the drill string when connecting or disconnecting the drill pipe. The method of claim 11,
The drill string handling unit comprises:
A clamp for clamping the drill string; And
A clamp elevating part provided on the drilled structure to elevate the clamp;
≪ / RTI > The method of claim 12,
Wherein the clamp-
A drill work provided on a drill floor of the drilling structure to raise and lower the clamp and connected to the clamp through a derrick; And
A plurality of rollers provided on the derrick to support a connecting member connecting the drawrows and the clamp;
≪ / RTI > The method according to claim 1,
A rotating shaft rotatably installed inside the body;
A connecting member connecting the rotating shaft and the drill pipe to rotate the drill pipe; And
A drill pipe rotation unit provided inside the body and having a rotation axis drive motor for rotating the rotation;
The drilling system further comprising: A drilling method for drilling underwater resources,
Securing a drill pipe support unit to hold the drill pipe at the seabed;
Drilling the drilling pipe connected to the drilling structure with the drill pipe supporting unit supporting the weight of the drill pipe at the sea floor by rotating the drilling pipe at the sea floor;
And returning the mud supplied to the drilling hole during the drilling operation,
In the mud returning stage, the mud is returned by the mud return unit to the drilling structure without a riser pipe,
Characterized in that the drill pipe is not rotated by the top drive. delete

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