KR101793959B1

KR101793959B1 - Semi-submersible drill rig with wide column span and lowered derrick

Info

Publication number: KR101793959B1
Application number: KR1020160004246A
Authority: KR
Inventors: 박승균
Original assignee: 서울대학교산학협력단
Priority date: 2016-01-13
Filing date: 2016-01-13
Publication date: 2017-11-06
Also published as: KR20170084867A

Abstract

The present invention improves the safety performance of the overturning of offshore structures such as semi-submersible drilling rigs, and it is possible to manufacture small and light-weight vessels having the same performance when used, thereby reducing the long- The width of left and right contour of columns is wider than the width of pontoons and decks. The drilling tower is used for large scale weight reduction and simultaneous weight down centering It is installed directly on the upper deck to improve the stability and reduce the size of the hull.

Description

{SEMI-SUBMERSIBLE DRILL RIG WITH WIDE COLUMN SPAN AND LOWERED DERRICK}

More particularly, the present invention relates to a semi-submersible drilling rig with wide column spacing and a low drilling column. More particularly, the present invention relates to a semi-submersible drilling rig, This large material is filled with permanent ballast to greatly improve the restoration ability of the horizontal sagittal strap, which eliminates the need for the ballast that is required for ordinary lines, and allows for wide column spacing and low drill tower to reduce the size of the ship without reducing the fundamental performance. Semi-submersible drilling rig.

Generally, the hull of semi-submersible drilling rig is divided into two rectangular diving hulls (hereinafter referred to as "pontoon"), four or more columns erected on top of the pontoon, And an upper deck unit. The two pontoons are firmly connected to each other by a connecting rod called a brace.

The maximum advantage of the above-mentioned hull is that it is possible to perform stable marine work because the influence of the wave is less in the Nether Cave because the water force is formed on the column portion, and therefore the action force of the wave on the hull is remarkably smaller than that of the general hull.

On the other hand, since the elevation profile of the columns is small, the buoyancy due to the waves is reduced, but the water plane area of the water line is small and the restoring force at the time of inclination is not large.

In particular, the drilling rig is installed on a high drilling derrick and loads heavy heavy consumables such as drilling pipes, risers, and muds on the upper deck. In order to secure the resilience that becomes insufficient due to the necessity, the pontoon and the column are inevitably enlarged in order to increase the number of the ballast water, and the existing design inevitably contains inherent inefficiency.

Korean Patent Publication No. 10-2013-0051259

SUMMARY OF THE INVENTION Accordingly, the present invention has been made in order to solve the above-mentioned problems, and it is an object of the present invention to provide a hull structure which is capable of reducing the size of hull, And to provide semi-submersible drilling rig with low drilling tower.

According to an aspect of the present invention, an upper half deck and a pontoon of a small semi-submersible hull are left as they are but if the lateral spacing of the columns is widened, .

The left and right outline widths of the columns are wider than the width of the upper deck. The upper surface of the column, which is not covered with the upper deck, can be used as a mooring deck for installing an anchor windlass.

The lower part of the column may be inclined toward the upper end of the pontoon and converged to be inclined and seated.

The inclination angle of the inclined portion may be provided within a range that does not hinder the elevator operation installed between the pontoons and the upper deck.

If the drill floor is removed from the drill floor and installed on the upper deck, the weight of the drill tower will be reduced and the center of gravity will be downgraded.

In the lower part of the drilling tower, a vertical trunk structure that surrounds the artillery section from below the upper deck is extended to a lower level than the double bottom floor of the upper deck unit for securing the vertical space required for installing risers and BOPs You can install a sella deck and a mural.

In mounting the BOP on the upper deck, the upper deck is dug so that the height of the non-opaque crane for loading the BOP into the lower part of the drilling tower is not too high, It should be created and connected to the portal.

In mounting the riser of the longest length of 90 feet to the upper deck of the smaller size, a running rail of the gantry type riser crane should be installed by projecting a part of the riser length to the outside of the upper deck and connecting a platform to the end of the upper deck .

In the pontoons, an intermediate deck was installed in four ballast tanks, and two bulk tanks, usually installed in a column, were installed downward one by two.

As described above, according to the present invention, according to the semi-submersible drilling line having the column width widening and the low drilling column, the performance is the same as that of the conventional semi-submersible drilling hull, and the hull is small and light, As a result, there is a good effect on investment and operational competitiveness.

Second, since the hull is small and light, thruster operation for maintaining its position is low, fuel consumption is low, and the number of ballast pump operations is small and the quantity of water to be treated is small, so fuel consumption can be reduced and fuel cost can be saved.

Third, the drill floor supporting the drilling tower and the support structure for the riser and drilling pipe injection device can be removed, which makes handling of heavy materials using the crane convenient, and the work to be done on the high place is greatly reduced, thereby improving the work efficiency and improving the health of the crew. There is an effect that can be done.

1 is a vertical cross-sectional view of a semi-submersible rig according to the present invention from the front to the stern side.
FIG. 2 is a side view of the semi-submersible drill ship from the right side to the left side according to the present invention.
3 is a bottom view of a semi-submersible drilling rig according to the present invention.
4 is a plan view of a semi-submersible drilling rig according to the present invention.
FIG. 5 is a plan view showing the bottom of the drilling tower of the semi-submersible drill ship according to the present invention. FIG.
6A is a cross-sectional view taken along the line "AA" in Fig.
6B is a sectional view taken along the line "BB" in Fig.
6C is a cross-sectional view taken along line "CC" in Fig.
6D is a cross-sectional view taken along the line "DD" in Fig.
7 is an exemplary view showing a vertically arranged column and access trunk of semi-submersible drilling rig according to the present invention.
8 is an exemplary view showing a state in which a lower portion of a bulk tank of a semi-submersible drill ship is installed downward on an intermediate deck of a pontoon.
9 is a sectional view of a pontoon of semi-submersible drilling rig according to the present invention.
10 is a plan view showing an upper deck of a semi-submersible drilling rig according to the present invention.
Fig. 11A is a self-weight estimating chart of the experimental design line, and Fig. 11B is a calculation of the restoring force coefficient (GM) of the loading line at the drafting time of the experimental design line.

Hereinafter, embodiments according to the present invention will be described in more detail with reference to the accompanying drawings and simple calculations.

Before describing the present invention, the following specific features, structures, and functional descriptions are merely illustrative for the purpose of describing an embodiment according to the concept of the present invention, and embodiments according to the concept of the present invention may be implemented in various forms , The embodiments set forth herein should not be construed as limiting.

In addition, although the embodiments according to the present invention can make various changes and have various forms, specific embodiments are illustrated in the drawings and described in detail herein.

It is to be understood, however, that the intention is not to limit the embodiments according to the concept of the present invention to any particular timekeeping form, and that all changes that come within the spirit and scope of the invention include equivalents and alternatives.

1 to 4, the linear shape to which the present invention is applied has a pontoon 100 and an upper deck 300 in the same shape as a normal line, but the interval between the columns 200 is widened, It can be seen that it is installed directly on the upper deck 300 without a drill floor which is a pedestal structure.

The main reason for this change is to improve the ability of rescue of small ships so that they can drill in 10,000 feet of water that can be operated by large ships. A specific method for improving the resilience capability is to increase the distance between the columns 200 by raising the metacenter to a higher position and lowering the center of gravity further, Moving to a lower position will lower the center of gravity.

The center of gravity is the center of buoyancy naturally caught by the various inclined conditions of the hull, that is, the center of the volume occupied by the hull in the water, Is concentrated in almost one place, and it is regarded as a peculiarity as this is a unique characteristic point. Mark the center of gravity as "M" and the center of gravity as "G" and use the distance GM between two points as a measure of the resilience. When G is low and M is high, the GM value becomes positive. The larger the value, the greater the restoration ability. If the GM value is less than 0, that is, if the value is negative, a small inclination causes the overturning moment rather than the restoring force to be applied. This is because the sine of the tilt angle and the GM's enemy (multiplied value) are the arm lengths of the restoring force moments generated by the inclined ship. This principle is not only the most basic ship stabilization theory of shipbuilding engineering, but also the fact that when the center of gravity of the object is in a low position, it is stable.

The width of the left and right contours of the column 200 is greater than the contour width of the pontoons 100 and the upper deck 300.

As described above, the effect of moving the metacenter M upward and downward by a wide spreading of the column 200 toward the outer periphery is calculated,

For example, the two pontoons 100 of the experimental design line are 100 m long, 17 m wide and 10 m deep, and the distance between the left and right outlines of the two pontoons 100 is 70 m.

The four columns 200 laid on the fore / aft side upper deck 300 of the pontoon 100 have a width of 17 m, a length of 16 m and a height of 25 m and a distance between the left and right outlines of the column 200 is 80 m.

The drainage volume of the underwater hull at 21m of the drilling waterline is 45,968㎥ (100 × 17 × 10 × 2 + 17 × 16 × 11 × 4) and the calculated center of buoyancy is 7.734m above the bottom.

In order to know the height up to the critical point M, it is necessary to know the length of the line segment BM, but the calculation is possible because it is defined that the area moment of the water line surface is divided by the drain volume. 17 × 17 × 1/12 + 16 × 17 × 31.5 × 31.5 = 1,105,768, where 31.5 is the distance from the center line of the ship to the midpoint of the waterline area.

Since BM = 1,105,768 / 45,968 .... 24,055m, the position of the center of gravity is 31.79m plus the umpire point 7.734m. As shown in Fig. 11, the estimated center point (G) at the time of loading of the experimental design line is about 27.6 m, which shows that there is sufficient margin for the stability (GM value).

That is, as shown in Figs. 11A and 11B, the gap between the raised center-of-gravity point M and the center-of-gravity point G is greatly increased.

Even if the anchor chain included in 3,237 tons is not loaded, the center point rises to 29.22 m, but it has a margin of more than 3.4 m in comparison with the height of 32.68 m at the new point of 18.1 m (the bill is omitted). )

As shown in FIGS. 1 to 4, the left and right outline widths of the column 200 are wider than the outline width of the pontoon 100.

The width of the left and right contour lines of the column 200 is larger than the width of the upper deck 300.

Accordingly, the upper surface of the column 200 exposed without being covered with the upper deck 300 can be used as a mooring deck 220 for installing an anchor windlass.

Thus, the width of the upper deck 300 is optimized to a required area irrespective of the width of the columns 200, and the upper surface of the column 200, which is not covered with the upper deck 300, The mooring deck (220), which is a mooring windlass installation site with a weight of about 250 tons and a depth of 9 m below the deck structure, contributes to the reduction of water consumption as well as the weight reduction of the hull.

Considering that the estimator of the experimental design line and the estimated center point are 27,000 tons and about 30 meters, the effect of downward adjustment of Windrass is 1 / 27,000 × (27.000 × 30-9 × 250) = 29.917m, Contributing to the 8.3cm reduction of the center of gravity.

As shown in FIG. 1, the lower part of the column 200 is inclined toward the center line of the water line so that the lower part of the column 200 can converge toward the upper deck 300 of the pontoon 100, do.

In this manner, the slope part 230 is installed so as to incline the lower part of the column 200 in a structural joining manner with the column 200 opened to the exterior side of the pontoon 100, The range is set to a range that satisfies the necessary stiffness of the hull and the installation of the elevator, which is a vertical connection path to the pontoons 100, and the arrangement capable of manually lifting emergency patients / casualties.

The amount of the horizontal braces 400 structurally interconnecting the two pontoons 100 is reduced by the spacing of the narrow pontoons 100 and the verticality of the vertical braces 410 supporting the drilling tower 600 is reduced The supporting efficiency is improved and the amount of the structure is reduced.

In this way, by installing the drilling tower 600, which is about 1,000 tons, directly on the upper deck 300 without a drill floor, at least 300 tonnes of steel reduction can be considered as common sense evaluation, and the center- 1 / 27,000 × (27,000 × 30-1,000 × 10) = 29.63 m, contributing to the downward movement of the center of gravity by 37 cm.

5 to 6, in the lower part of the drilling tower 600, a cellar deck (not shown) is installed so as to secure a height of a vertical space necessary for installing a riser and a BOP (Blow Off Preventer) deck 340 and the door frame structure are projected downward from the bottom of the upper deck 300 to extend.

In addition, the sanitary ware 340 and the door frame are left untouched, and the sanitary ware protecting trunk 341, which encloses the sella deck 340, further extends downward.

Below the drilling tower 600, a vertical space of about 10 m or more is required for the BOP 10 and the riser installation work. The bottom of the vertical space is called a Sella deck 340 and an opening called a moon pool It is drilled.

However, since the height from the upper deck 300 to the bottom plate is 9 m, the sella deck 340 is disposed at a necessary position and the culture protection trunk 341 wrapping around the sella deck 340 is moved down by at least 4 m If the overall structure depth of the vertical trunk is extended to 13 m and the structure thickness of the sella deck 340 is made 1 m, the height of the vertical space up to the sella deck 340 becomes 12 m, which is a reasonable height.

At this time, the air gap (also referred to as an air gap / air draft) from the drilling draft 21 m to the sella deck 340 was 11 m, and a level value corresponding to a problem-free category was obtained.

Also, if the anchor chain is not loaded in the sea area where the marine condition is very bad, the water line will be lowered to 18.1m and the air gap will increase up to 3m, up to 3m, up to the sella deck (340).

In addition, the present invention can reduce the obstacles to the operation that can be received from the blue color by further reducing the structure of the protection work trunk 341 as another design option that can be selected. Of course, the blue color can be applied to the outer wall of the protection work trunk 341 Is the part of the force that causes the hull shaking, so it is a matter of choice for the operator to take the local circumstances of the mainstream site into consideration.

As shown in FIG. 6D, a non-opaque vessel 313 for charging the BOP 10 to the lower part of the drilling tower 600 when the BOP 10 is mounted on the upper deck 300, So as to reduce the height of the upper deck 300 and form a recess-shaped non-owning stock 331 on the main deck 330.

In addition, the recessed area of the non-operative stockyard 331 must extend from the non-opaque (BOP)

7, an access trunk 210 is installed perpendicularly to the column 200, and the seawater-side shell plate of the access trunk 210 is installed in a double-walled structure to prevent flooding do.

As shown in FIG. 8, the pontoon 100 is provided with an intermediate deck 110 in four ballast tanks 120, two bulk tanks 111 each having 20 to 25 tons in one place, Downward.

When the bulk tank 111 is 180 ton, the calculation is 1 / 27,000 × (27,000 × 30-180 × 12) = 29.92 m, and the center downward effect is 8 cm.

As shown in FIG. 9, when the bottom portion of the pontoon 100 is filled with a ballast material, centering down is achieved most efficiently.

At this time, a simple calculation to show that the dramatic effect is obtained by small measures though not included in the calculation of the center of the experimental design line is as follows. For example, in a compartment of the pontoon (100) Four ballast tanks 120 each having a length of 10 m and a width of 5 m are provided in each of the left and right pontoons 100.

(27,000 × 30 + 1,500 × 1) × 1 / (27,000 + 1,500) = 28.474 If the iron ore with a specific gravity of 4.48 is filled, it can be charged up to 1,500 tons even if the filling rate is considered. m. The increase of the draft caused by the increase of 1,500 tons is equivalent to 1,463,4㎥ of sea water volume divided by the repair area of 1,088㎡, which is 1.345m.

Thus, it is a good choice for designers as to which point is the focus of optimization while proceeding with detailed design.

As shown in FIG. 10, a portion of the riser length protrudes to the outside of the upper deck 300 when the riser (not shown) of the longest 90 feet is installed despite the narrow upper deck 300 A platform is connected to the end of the upper deck 300 so as to pass therethrough so as to install a running rail 315 of a gantry type riser crane 312.

That is, since the riser must be held on both ends by the riser cranes 312, the crane driving wheels must be at the end of the stockyard.

Once again, as described above, by increasing the distance from the center of gravity (G point: from the center of gravity) to the metacenter by applying the column spacing widening according to the present invention and the semi-submersible drilling line applied with the low drilling tower, To raise the sigh to the higher and to lower the center to the lower.

As a means for maximizing the depth of field, the pontoons 100 having no role and the upper deck 300 are left as they are and the spacing between the left and right columns 200 is enlarged. The drill tower 600 is directly placed on the upper deck 300 without providing a drill floor to support the drill tower 600, so that a series of weight saving and downward weight centering can be achieved .

In addition, since the lower part of the column 200 is inclined to the inner side, that is, the center line direction, the lower end part of the column 200 can be stably converged without being shifted on the upper part of the pontoon 100, .

A riser and a BOP 10 are installed between the drilling tower 600 and a sella deck 340 having a moon pool. The drilling tower 600 is installed on the upper deck 300 The installation space of the riser and the BOP 10 is insufficient so that the door protecting trunk 341 forming the door space is extended downward to a position lower than the lower portion of the upper deck 300, The space for installing the riser and the BOP 10 between the floor and the sella deck 340 is secured.

Therefore, according to the present invention, it is possible to design a product by utilizing characteristics of various sizes, features, and arrangements according to the characteristics of the marine environment and the operator's preferences, and thus it can be seen that the industrial utilization is high.

As described above, the present invention is not limited to the above-described specific preferred embodiments, and any person skilled in the art can make various modifications without departing from the gist of the present invention. It is to be understood that such changes and modifications are intended to fall within the scope of the appended claims.

10: BOP 100: pontoon
110: middle deck 111: bulk tank
120: ballast tank 200: column
210: access trunk 220: mooring deck
230: slope part 300: upper deck
311: Riser cage 312: Riser cranes
313: non-operative cranes 315: running rails
320: middle deck 330: main deck
331: Bifoan stock 340: Sella deck
341: Protecting the trunk of the picture frame 400: Horizontal brace
410: Vertical Place 600: Drilling Tower

Claims

A pontoon forming buoyancy, an upper deck installed on the upper part of the pontoon and equipped with various equipments necessary for drilling, and a door pool being formed at a central part thereof, a plurality of columns connecting the pontoon and the upper deck, Claims [1] A semi-submersible drilling rig having a drilling tower installed at an upper portion thereof and having a water line surface in a column,
The left and right outline widths of the column are set wider than the outline width of the pontoon,
The drilling tower installed on the upper part of the door frame is installed directly on the upper deck so as to improve the restoring force and downsize the hull by downsizing the center of gravity,
The left and right widths of the column are wider than the width of the upper deck. The upper surface of the column, which is not covered with the upper deck, is used as a mooring deck for installing an anchor wind lath,
In the lower part of the drilling tower, in order to secure the height of the vertical space necessary for installing risers and non-ops (BOPs), the sella deck and the portal structure are extended by projecting downward from the bottom of the upper deck, The deck is wrapped around the deck,
In order to reduce the height of the non-opaque crane which loads the BOP into the lower part of the drilling tower, a non-opaque stockyard is formed on the main deck, Is formed as a full path from the BOP mounting position to the door frame,
Characterized in that a riser of the gantry type riser crane is installed by protruding a part of the length of the 90 feet riser to the outside of the upper deck and connecting the platform to the end of the upper deck when the riser is mounted on the upper deck, Semi-submersible drilling rig with drilling tower.

delete

The method according to claim 1,
Wherein the left and right outline widths of the column are set to be wider than the outline width of the pontoon and the upper deck, and the semi-submersible drill ship to which the column spacing widening and low drilling tower is applied.

The method according to claim 1,
Wherein a lower portion of the column is inclined toward the centerline of the waterline so as to be converged and seated toward the upper end of the pontoon and assembled firmly.

5. The method of claim 4,
Wherein the inclination angle of the inclined portion is set within a range that does not interfere with the operation of an elevator provided between the pontoon and the upper deck, and the semi-submersible drilling rig to which the low-angle drilling column is applied.

delete

The method according to claim 1,
The pontoon is equipped with an intermediate deck in four ballast tanks and two bulk tanks downward in one place. The semi-submersible drilling rig with wide column spacing and low drilling tower.