US20160040383A1

US20160040383A1 - Floating system integration methodology

Info

Publication number: US20160040383A1
Application number: US14/454,487
Authority: US
Inventors: Robert Kwan Meng Seah; David J. Wisch
Original assignee: Chevron USA Inc
Current assignee: Chevron USA Inc
Priority date: 2014-08-07
Filing date: 2014-08-07
Publication date: 2016-02-11

Abstract

Disclosed is a floating system integration method involving integrated lifting equipment. The topsides and the hull are integrated at a first location such as a dock. The floating system is then transported to a second location such as an offshore location. The topsides is lifted after transportation to the second location. In addition to eliminating the need for heavy lifts, the method provides additional stability during transportation to the second location as the topsides is in a lowered position and has not been lifted yet.

Description

FIELD OF THE INVENTION

This invention relates to a floating system integration methodology. In particular, this invention relates to an integration method for a floating system involving integrated lifting equipment.

BACKGROUND OF THE INVENTION

Offshore facilities may be either floating or settled on the seafloor. The components of a floating system typically include a hull, a topsides, a support mechanism, a floating mechanism, and equipment. The current methodology for the integration of floating systems typically involves quayside, float-over, or offshore heavy lifts. Such lifts are required as the operational draft of the floating platforms is much deeper than the depth of the construction yard dock. With respect to quayside integration, facilities to perform quayside integrations are limited and involve transportation routes for the individual components to the facility and for the integrated system to the site. With respect to offshore integration, offshore lifts require specialized heavy lift vessels, typically which have a long lead time, and are subject to prevailing weather. In addition, offshore integration often carries a significant cost premium required to mobilize personnel and material to the site. Both the quayside and offshore are also schedule limited due to the number of units and facilities.
An alternative method for integration is the float-over method. In the float-over method, the topsides is floated to the site either on a barge or pontoons, lifted or jacked up, and set down atop the platform. This method requires the additional barge or pontoons. In addition, additional cost is associated with this offshore integration method. Another method for integration is to build the topsides next to a dry dock containing the hull and to skid the topsides directly on top of the hull. This method requires a specialized dry dock to be available. Further, an integration variant which can achieve the benefits of a deeper draft is to use an extensible draft platform in which a secondary structure is lowered from the main structure providing the buoyancy. However, these structures still require heavy lift capability.
To address these scheduling and costs issues, it would be desirable to provide a method for the integration of floating systems involving integrated lifting equipment.

SUMMARY OF THE INVENTION

According to one embodiment, a floating system integration method involving integrated lifting equipment is disclosed. The method includes providing a topsides and a hull at a first location.
In one embodiment, the topsides is constructed atop a plurality of skid rails. The topsides includes a deck. The deck may include many embodiments. For example, the deck may be a single-level or multi-level structure and may include other components or modules such as living quarters and/or a rig.
In one embodiment, the hull includes a floatation device, a plurality of columns, and a plurality of integrated lifting mechanisms. In one embodiment, the floatation device is a pontoon. In another embodiment, the pontoon is a ring pontoon. The ring pontoon can include four connected pontoons, two pontoons side by side, or a single large pontoon (also referred to as a barge). The flotation device is a typical component of the hull. The flotation device may be a temporary component or a permanent component. In one embodiment, the plurality of columns can include two or more columns. In one embodiment, the plurality of columns includes six columns. The plurality of integrated lifting mechanisms may include many embodiments. For example, in one embodiment each of the plurality of columns may be equipped with an integrated lifting mechanism. In another embodiment an integrated lifting mechanism is not needed for every column and the plurality of integrated lifting mechanisms may include two integrated lifting mechanisms. In the embodiment where each column is not equipped with an integrated lifting mechanism, guide wires may be used to assist with the lifting process. In some embodiments, the integrated lifting mechanism may also be equipped with a locking mechanism. In some embodiments, a single column may be equipped with multiple integrated lifting mechanisms—for example, side by side or one integrated lifting mechanism above the other integrated lifting mechanism. A number of lifting mechanisms are known in the art. For example, the lifting mechanism (also known as a jack-up mechanism) may comprise a rack and pinion system, a plurality of short stroke hydraulic rams with locks, or a modified mooring chain with chain jacks. In one embodiment where the lifting mechanism is a modified mooring chain with chain locks, the lifting mechanism may later be used during installation for mooring.
In one embodiment, the hull is a semisubmersible hull. In another embodiment, the hull is a tension leg platform. In another embodiment, the plurality of columns may be atypically tall for deep draft capabilities.
In one embodiment, the first location is a dock of moderate depth. In one embodiment, both the topsides and the hull are constructed locally at the first location. In another embodiment, the topsides is constructed locally at the first location and the hull is constructed remotely and floated to the first location for integration with the topsides. In another embodiment, the hull is constructed locally at the first location and the topsides is constructed remotely and transported to the first location for integration with the hull. In another embodiment, neither the topsides nor the hull is constructed at the first location—both the topsides and the hull are constructed remotely and transported to the first location for integration.
In addition to addressing scheduling and costs issues, the floating system integration method involving integrated lifting equipment may also reduce long distance transport and may also enable local fabrication in remote locations. For example, in one embodiment, the topsides and hull may both be built locally at the first location.
In one embodiment, as part of the integration, the topsides is skidded onto the ring pontoon and between the plurality of columns of the hull at the first location. No cranes and no heavy lifts are needed for this integration step. Next, the topsides is mated with the integrated lifting mechanisms creating a floating system comprising the topsides and the hull at the first location. After the integration of the floating system, the floating system is towed to a second location. In one embodiment, the second location is an offshore field. In addition to eliminating the need for heavy lifts, the method provides additional stability during transportation to the second location as the topsides is in a lowered position and has not been lifted yet. In addition, due to the lowered position, additional sponsons for stability during transportation may not be required. At the second location, the topsides is lifted up to the plurality of columns with the integrated lifting mechanisms. After lifting, the hull is ballasted to the operational depth and the topsides is secured. Finally, the specific installation will depend on the second location.
In another embodiment, additional wings can be added to augment the area available. The wings could be connected to the topsides at either the first location or the second location. In another embodiment, a flare boom can be added. The flare boom could be connected to the topsides at either the first location or the second location.

BRIEF DESCRIPTION OF THE DRAWINGS

The description is presented with reference to the accompanying figure in which:

FIG. 1 illustrates an overhead view of one embodiment of the floating system integration method.

FIG. 1A illustrates a side view of one embodiment of the floating system integration method.

FIG. 2 illustrates an overhead view of one embodiment of one of the steps of the floating system integration method.

FIG. 2A illustrates a side view of one embodiment of one of the steps of the floating system integration method.

FIG. 3 illustrates a side view of one embodiment of one of the steps of the floating system integration method.

FIG. 4 illustrates a side view of one embodiment of one of the steps of the floating system integration method.

FIG. 5 illustrates a side view of one embodiment of one of the steps of the floating system integration method.

FIG. 6 illustrates a side view of one embodiment of one of the steps of the floating system integration method.

FIG. 7 illustrates an embodiment with atypically tall columns for deep draft capabilities.

FIG. 8 illustrates an overhead view of an embodiment with additional wings attached to the topsides of the floating system.

FIG. 8A illustrates a side view of an embodiment with additional wings attached to the topsides of the floating system.

FIG. 9 illustrates an embodiment with a flare boom attached to the topsides of the floating system.

DETAILED DESCRIPTION OF THE INVENTION

In one embodiment, a floating system integration method involving integrated lifting equipment is disclosed. FIG. 1 illustrates one embodiment of the floating system integration method. An overhead view is shown. A topsides 101 and a hull 103 are provided at a first location for integration. In one embodiment, the topsides 101 and the hull 103 are constructed and integrated at the first location. In another embodiment, the topsides 101 is constructed at the first location and the hull 103 is constructed at a third location and floated to the first location for integration with the topsides 101. In another embodiment, the hull 103 is constructed at the first location and the topsides 101 is constructed at a third location and transported to the first location for integration with the hull 103. In another embodiment, neither the topsides 101 nor the hull 103 is constructed at the first location—both the topsides 101 and the hull 103 are transported to the first location for integration.
The topsides 101 is constructed atop a plurality of skid rails 102. In the embodiment shown in FIG. 1, the topsides 101 include a deck 107. The deck 107 includes living quarters 104 and a rig 105. In the embodiment shown in FIG. 1, the hull 103 comprises a floatation device, a plurality of columns, and a plurality of integrated lifting mechanisms. In the embodiment shown in FIG. 1, the floatation device is a ring pontoon including four connected pontoons 110, 111, 112, 113. In the embodiment shown in FIG. 1, the plurality of column includes four columns 120, 121, 122, 123. Each of the four columns 120, 121, 122, 123 is equipped with an integrated lifting mechanism 130, 131, 132, 133. FIG. 1A illustrates a side view including the topsides 101 with one skid rail 102 shown and the hull 103 with one pontoon 112 shown and two columns 121, 122 shown.
In another embodiment, the topsides may not include skid rails. Instead, the topsides may include wheels and be wheeled onto the hull. One embodiment of the steps of the integration method is shown in FIGS. 2 through 5. Variations may be made to both the order and location of the following steps.
As shown in the overhead view of FIG. 2, in one embodiment, the topsides 101 is skidded along the plurality of skid rails 102 onto the ring pontoon 110, 111, 112, 113 and between the plurality of columns 120, 121, 122, 123 of the hull 103 at the first location. No cranes and no heavy lifts are needed for this integration step. After skidding, the topsides 101 is mated with the integrated lifting mechanism of each of the plurality of columns of the hull 103 creating a floating system 140 comprising the topsides 101 and the hull 103 at the first location. FIG. 2A illustrates a side view of the floating system 140 including the topsides 101 with one skid rail 102 shown and the hull with one pontoon 112 shown and two columns 121, 122 shown.
In one embodiment, after the integration of the topsides 101 and hull 103, the floating system 140 is towed to a second location as shown in the side view of FIG. 3. As shown in FIG. 3, the topsides 101 is in a lowered position and has not been lifted yet.
In the next integration step, in one embodiment, the topsides 101 is lifted up to the plurality of columns with the integrated lifting mechanism of each of the plurality of columns. Lifting can include raising or elevating, FIG. 4 illustrates a side view including the topsides 101 lifted up to the two columns 121, 122 shown with the integrated lifting mechanisms 131, 132 not shown—also not shown are two additional columns 120, 123 and two additional integrated lifting mechanisms 130, 133. In one embodiment, after lifting, the hull 103 is ballasted to the operational depth and the topsides 101 is secured.
Finally, as shown in the side view of FIG. 5, in one embodiment the installation of the floating system 140 at the second location includes hooking up the mooring lines 160. The embodiment shown in FIG. 5 is a semisubmersible hull.
In another embodiment, as shown in FIG. 6, the hull is a tension leg platform. In this embodiment, the installation of the floating system 140 at the second location includes connecting the tendons 170.
As shown in FIG. 7, in another embodiment, the plurality of columns 180 may be atypically tall for deep draft capabilities.
As shown in the overhead view of FIG. 8, in another embodiment, at least one wing 200 can be added to augment the area available. The at least one wing 200 could be connected to the topsides at 101 either the first location or the second location. As shown in the side view of FIG. 8A, an additional wing can be attached to the topsides 101 of the floating system.
As shown in FIG. 9, in another embodiment, a flare boom 300 can be added. The flare boom 300 could be connected to the topsides 101 at either the first location or the second location. Another embodiment with a flare boom is also illustrated in FIG. 6. As shown in FIG. 6, a flare boom 108 can be added. The flare boom 108 could be connected to the topsides 101 at either the first location or the second location.
The above methods may also be used with other topsides/hulls configurations including, but not limited to, two decks with one deck above the other deck or two decks side by side.
While the methods of this invention have been described in terms of preferred or illustrative embodiments, it will be apparent to those of skill in the art that variations may be applied to the process described herein without departing from the concept and scope of the invention. All such similar substitutes and modifications apparent to those skilled in the art are deemed to be within the scope and concept of the invention as it is set out in the following claims.

Claims

What is claimed is:

1. A method for the integration of a floating system comprising:

a. providing a hull at a first location wherein the hull comprises a floatation device, a plurality of columns, and a plurality of integrated lifting mechanisms;

b. providing a topsides at the first location;

c. moving the topsides onto the floatation device and between the plurality of columns at the first location;

d. mating the topsides with the plurality of integrated lifting mechanisms and creating a floating system comprising the topsides and the hull at the first location; and

e. lifting the topsides up to the top of the plurality of columns with the plurality of integrated lifting mechanisms.

2. The method of claim 1 wherein the topsides is constructed atop a plurality of skid rails.

3. The method of claim 1 wherein the topsides includes wheels.

4. The method of claim 1 further comprising ballasting the hull to operational depth, securing the topsides, and installing the floating system.

5. The method of claim 1 further comprising towing the floating system to a second location.

6. The method of claim 5 further comprising ballasting the hull to operational depth, securing the topsides, and installing the floating system at the second location.

7. The method of claim 1 wherein the plurality of integrated lifting mechanisms comprises a rack and pinion system.

8. The method of claim 1 wherein the plurality of integrated lifting mechanism comprises a plurality of short stroke hydraulic rams with locks.

9. The method of claim 1 wherein the plurality of integrated lifting mechanism comprises a modified mooring chain with chain jacks.

10. The method of claim 1 wherein the topsides and the hull are constructed at the first location.

11. The method of claim 1 wherein the topsides is constructed at the first location and the hull is constructed at a third location and floated to the first location.

12. The method of claim 1 wherein the hull is constructed at the first location and the topsides is constructed as a third location and transported to the first location.

13. The method of claim 1 wherein the topsides and the hull are transported to the first location.

14. The method of claim 1 wherein the hull is a semisubmersible hull.

15. The method of claim 1 wherein the hull is a tension leg platform.

16. The method of claim 1 wherein the plurality of columns are atypically tall.

17. The method of claim 1 wherein the topsides further comprises at least one wing.

18. The method of claim 1 wherein the topsides further comprises a flare boom.