NO340840B1

NO340840B1 - Method and a system for performing several well activities.

Info

Publication number: NO340840B1
Application number: NO20151749A
Authority: NO
Inventors: Rune Stanghelle; Håkon Klepsvik; Thomas Borsholm
Original assignee: Odfjell Drilling As
Priority date: 2015-12-18
Filing date: 2015-12-18
Publication date: 2017-06-26
Also published as: KR102629169B1; SG11201804955YA; US20170175457A1; NO20151749A1; CN108463610A; WO2017102109A1; EP3390762A1; KR20180125443A; EP3390762B1; MX2018007373A

Description

The present invention rektes to a method and a system for performing several well activities, comprising a main platform with a main drilling unit with a drill floor and equipped with several distributed well centers on a wellhead spread.

BACKGROUND OF THE INVENTION

This invention relates to a novel method for well operations. More specifically, this invention relates to a method and apparatus for conducting simultaneous operations on several wells by utilizing one main drilling unit with several distributed well centers or "drilling pods". This can also be defined as Multi well drilling, from one drilling unit.

For development, drilling multiple wells will normally be drilled from one platform or area. On shallow water drilling, wellhead jacket platforms are normally used. For some wellhead jackets it is normal to use a drilling module placed on an x-y skid module for moving between the different wells. For wellhead jacket platforms without drilling module or if the platform drilling module is removed after the wells are finished, or the drilling module is not fit for further use due to different reasons (regulations, certification, low efficiency), a Jack-up rig may be a solution for further drilling, workover or plugging the wells on this platform.

The publication US 2008/044234 Al discloses a support framework mounted on a self-elevating platform. The frameworks are retractable to allow the self-elevating unit to position itself closer to the jackets than would otherwise be possible.

The publication US 6932553 Bl, discloses a multipurpose system for a drilling and well intervention made of a pivotable, slideable cantilever on a platform adapted to pivot and slide along an x-y axis.

The publication US 6056071 A, discloses a multi-activity drillship with a single derrick and a multiple tubular activity stations within the derrick wherein primary drilling activity may be conducted from the derrick and simultaneously auxiliary drilling activity may be conducted from the same derrick to reduce the length of the primary drilling activity critical path.

The present invention is intended to increase the efficiency of the work by being able to work on several wells at the same time by use of one main drilling unit and one or several smaller drilling units (drilling pods), and by this method reduce the time and cost for each well.

The present invention uses two or more separate independent "drilling pods" with short hoisting masts situated on the different wells supported by a drilling unit with an elevated drill floor, such as a jack up rig. The elevated drill floor can skid above the drilling pods and assist to improve efficiency or increase capacity of some operations like; trip in and out with drill pipe, run or pull large casings/tubings/conductors. The elevated drill floor can be equipped with large storage capacity and allow for offline activities.

A large jack-up with drill floor on the cantilever or an elevated drilling module, with reach to all or a portion of the well slot positions, is required to enable increased efficiency for the overall operation. The drilling unit can handle the installation, and support the operation of the "drilling pods" with; accommodation, power, air, water, hydraulics, mud, cement, cuttings handling, bop control fluid and drain fluid handling in addition to tubular and well tools logistics. The drilling control system for the elevated drilling rig can be able to take over the control for each "drilling pod". The elevated drilling rig can have separate operation rooms where the support of the "drilling pod" can be done. Service companies can assist the simultaneous well operations from the drilling areas on the drilling unit or the wellhead deck or surroundings.

Each of the "drilling pods" can have its own driller/operator cabin, where full control of the operation shall be possible. The units can be made such as they are optimized for their intended purpose with an optimal footprint, height and weight allowing close by operations as well as easy mobilization by the main drilling unit on to the wellhead deck. Only a few lifts can be required to enable fast rig up of the "drilling pods". The "drilling pods" can be able to trip to the specified depth, drill, ream, circulate and set plugs as a normal drilling rig as well as facilitating for other well operations such as wireline, coiled tubing, snubbing, etc. The BOP can be placed in the substructure of the "drilling pods", and the kill and choke lines connected back to the main drilling unit by high-pressure hoses. The rigs shall meet the governmental regulations and international regulations for the equipment.

The above described main drilling rig and the "drilling pods" units will be able to skid independently between well slots and work independently in a planned pattern to obtain high efficiency for the work. By planning the well sequence, it can be possible that only one unit at the time is working in the reservoir section. For some periods, the main drilling rig can perform well operations adjacent to the "drilling pods" such as pulling and lay out conductors, which has already been cut below ground. At the same time, the two or more drilling pods are working on other wells. Even with two drilling pods, this enable up to three well operations at the same time supported from one main drilling rig.

It may also be possible to get started with other well operations such as wireline operations or coiled tubing operations on wells not being operated on by the "drilling pods" in order to perform well killing, intervention or similar. If the main drilling unit needs repositioning to reach all wells on the well spread, such operations may provide operational progress on the wells program until the weather allows the moving of the main drilling rig to a new position with an extended coverage of the platform.

By including other well service equipment and services such as wireline units, coil tubing units or more than two drilling pods further efficiency can be achieved. This method can be used for drilling, completion, intervention, plug and abandonment and other well operations. The space and capacities of the main drilling unit may be limiting the number of simultaneous operations, which can be possible.

The operating concept of drilling from two drill floors at different elevations in the same well and on several wells simultaneously can ideally be done by use of a jack-up rig, but can also be done by an elevated drilling rig on a fixed offshore installation or use of a land rig on elevated skid beams or similar, as well as on subsea wells using a mobile offshore drilling rig, drill ship, drill barge or similar above drilling pods situated below the main drilling rig.

The drilling pods can either be operated locally by operator on the unit or remotely from the main drilling rig.

OBJECTS OF THE INVENTION

It is a specific object of the invention to provide a novel method and apparatus utilizing a main drilling rig to support the operation of several well centers. The new idea of using two or more module rigs optimized for size and weight supported from the main drilling rig with the necessaryUtilities, and to be able to position the main drilling rig directly above the drilling pods to assist with heavy lifts and long trips, compensating for the limited capabilities built into the drilling pods. The combination of the drilling pods and main drilling rig will by this obtain a considerably higher efficiency than the traditional drilling rig alone and will be able to work on simultaneous wells located on a relative narrow well spread area.

It is another object of the invention to provide a novel method and apparatus for drilling several wells simultaneously by use of smaller drilling pods assisted by an elevated high spee drilling unit to increase the efficiency of the total operation by performing tubular operations in the bigger derrick and other well operations by the smaller drilling pods.

It is a related object of the invention to provide a novel drilling method and apparatus where the distributed well centers can be utilized to reduce the time consequence of equipment breakdown, as progress will still be made with a functional "drilling pod" or main derrick, and thus enhancing the reliability of the operation.

It is a further object of the invention to provide a novel drilling method and apparatus for shallow water drilling from a jack-up where the distributed well centers can be used to reduce the need to wait for weather window for reposition the jack-up as the drilling pods may be skidded out of reach from the jack-up and proceed well operations as well as tubular operations on such wells.

It is also an object of the invention to provide a novel drilling method and apparatus for drilling from a fixed offshore installation or land rig where the distributed well centers can be used to reduce time and cost for field development and well decommissioning (Plug & Abandonment).

BRIEF SUMMARY OF PREFERRED EMBODIMENTS OF THE INVENTION

A preferred embodiment of the invention which is intended to accomplish at least some of the foregoing objects comprises distributing well activities to "drilling pods" to carry out several simultaneous drilling or well operations supported from one drilling unit such as a jack-up, drilling module, drillship, tension leg platform, jacket, land rig or semi-submersible.

The distributed well activities are obtained by placing "drilling pods" on the wellhead platform (wellhead spread), jacket or similar in order to carry out well operations such as drilling, reaming, milling and similar from the "drilling pod". The "drilling pod" is supported by umbilicals and service loops from the main drilling unit in order to provide the necessary power andUtilities from the main drilling unit to the distributed well centers.

The above mentioned objects are achieved with a system for distributed well activities, comprising a main drilling unit with a main drilling rig with a drill floor equipped with one or more of well centers, set back/racking area, racking machines, catwalk machinery and iron roughnecks, said main drilling rig is placed on a skiddable deck or cantilever, wherein a wellhead spread is placed adjacent and below the cantilever or skiddable deck of the main drilling unit, said wellhead deck comprises several drilling pods, where each drilling pod has its own drilling equipment for performing well operations, and each drilling pod is being arranged for simultaneously well operations in separate wells, while being supported by the main drilling rig.

Similarly, the same can be achieved for subsea wellhead templates by use of floating main drilling rig and suitable drilling pods.

The wellhead platform spread may comprise distributed well centers, i.e. drilling pods.

The main drilling unit can be a jack-up rig standing on support legs and with a barge that can be raised or lowered, said jack-up rig is further equipped with the cantilever with the main drilling rig, where the cantilever can be driven or skidded out over water, such that the main drilling rig is above an operational area to perform desired well operations.

The main drilling unit can also be other solutions with elevated movable drill rig able to work above the drilling pods.

The drilling pods can each comprises a mast, drill floor and BOP, and in the mast of the drilling pod, can there be a rotary drilling machine, which is adapted to drive a tubular through the BOP and into a desired wellhead.

The main drilling unit can comprise a driller's cabin/control station connected by umbilicals to the equipment on the wellhead deck, for control and operations of the drilling pods and equipment on the wellhead deck.

The main drilling unit can support the drilling pods and other equipment on the wellhead deck with all main services andUtilities, such as mud, power, hydraulics and similar.

The above mentioned objects are also achieved with a method for distributed well activities, comprising a main drilling unit with an elevated main drilling rig on a skiddable cantilever equipped with one or several well centers, and a wellhead spread placed adjacent and below the cantilever of the main drilling unit, wherein the method comprises the steps of: (a) deploying from the elevated main drilling unit several drilling pods on a well deck of the wellhead spread; (b) run well operations to a first well from the main drilling rig through a first drilling pod on the wellhead spread; (c) break the connection between the main drilling rig and the first drilling pod; (d) proceed with drilling operations in the first well using the first drilling pod; (e) move the main drilling rig to a position above a second drilling pod on the wellhead spread; (f) run well operations in a second well from the main drilling rig through the second drilling pod on the wellhead spread; (g) break the connection between the main drilling rig and the second drilling pod; and (h) proceed with drilling operations in the second well using the second drilling pod.

The elevated drilling rig can perform preparations for the next activity, such as making up bottom hole assembly or rack up or down casing, while not supporting one of the drilling pods.

The main elevated drilling rig in step (b) can be tripping in with bottom-hole assembly through the first drilling pod's rotary bushing and BOP, and when reaching total well depth (TD) the drill string is landed in said drilling pods rotary bushing and an iron roughneck machine on the drilling pod breaks the connection freeing the main drilling rig for other operations.

The main drilling rig can move over immediately to the second drilling pod, after breaking the connection between the main drilling rig and the first drilling pod, to assist the second drilling pod while the first drilling pod is drilling ahead using local pipe storage.

The elevated main drilling rig in step (f) can be tripping in with the bottom hole assembly to TD through the second drilling pod, and when reaching TD the string is landed out in the rotary bushing on the second drilling pod and an iron roughneck breaks the connection releasing the drill string from the elevated main well center, while the second drilling pod starts drilling by use of its own local drill pipe storage.

The elevated main drilling rig can prepare the casing section for the first drilling pod, move over and when ready, pull out the drill string from the first drilling pod and then run in the casing section through the drilling pod's rotary bushing and BOP.

When the run is close to be completed, the casing landing string can be transferred to the drilling pod, which is landing out the casing.

THE DRAWINGS

Figure 1 illustrates a drilling pod for use in the invention.

Figure 2 illustrates a jack-up drilling unit for use in the invention.

Figure 3 illustrates a jack-up drilling unit and a drilling rig and drilling pods for use in the invention.

Figure 4 illustrates a drill floor on a drilling rig.

Figure 5 shows a comparison between standard drilling unit and distributed well concept according to the invention.

DETAILED DESCRIPTION

A jack-up rig or a self-elevating unit is a type of mobile platform that consists of a buoyant hull fitted with a number of movable legs, capable of raising its hull over the surface of the sea. The buoyant hull enables transportation of the unit and all attached machinery to a desired location. Once on location the hull is raised to the required elevation above the sea surface supported by the seabed. The legs of such units may be designed to penetrate the seabed, may be fitted with enlarged sections or footings, or may be attached to a bottom mat. A jack-up rig is regarded as well-known to a skilled person and is therefore not described in detail, but a typical jack-up rig is in general discussed later in the description.

A jack-up is floating barge fitted with long support legs that can be raised or lowered. The jack-up is maneuvered (self-propelled or by towing) into location with its legs up and the hull floating on the water. Upon arrival at the work location, the legs are jacked down onto the seafloor. Then "preloading" takes place, where the weight of the barge and additional ballast water are used to drive the legs securely into the sea bottom so they will not penetrate further while operations are carried out. After preloading, the jacking system is used to raise the entire barge above the water to a predetermined height or "air gap", so that wave, tidal and current loading acts only on the relatively slender legs and not on the barge hull.

Modern jacking systems use a rack and pinion gear arrangement where the pinion gears are driven by hydraulic or electric motors and the rack is affixed to the legs.

Jack-up rigs can only be placed in relatively shallow waters, generally less than 120 meters (390 ft) of water. However, specialized classes of jack-up rigs known as premium or ultra-premium jack-ups are known to have operational capability in water depths ranging from 150 to 190 meters (500 to 625 feet).

Fig. 2 is a typical drawing of a jack-up drilling rig 10 suitable for use together with the distributed well concept to perform effective tubular operations through a drilling pod and then transfer the operation back to the pod for performing slower drilling, milling or similar operations. The jack-up rig comprises a barge 12 fitted with long support legs 14 that can be raised or lowered, wherein said support legs 14 are placed on the sea floor 18. As shown, the barge 12 is located above the sea level 16 at a desired level. The jack-up rig 10 is further equipped with a cantilever 20 with a main drilling unit 22, and where the cantilever can be driven or skidded out over the water, such that the main drilling unit 22 is above an operational area to perform the desired drilling operations. The operational area is indicated by the two vertical dotted lines running down from the cantilever 20. The main drilling unit 22 is equipped in a normal manner with a drilling mast/derrick 24, drilling machinery 26 and drill floor 28.

Fig 1 shows a typical drawing of a "drilling pod" 30 with mast 32, drill floor 34 and BOP 36. The BOP is located above the wellhead 42. In the mast 32 of the drilling pod 30 is a rotary drilling and hoisting machine 38 fitted, and which is adapted to drive a tubular 40 through the BOP 36 and into a desired wellhead 42. Simple "drilling pods" like this is suitable for use in the distributed well activity concepts. The drilling pods can also be more advanced if the well operations require. Fig 3 is a typical setup for the distributed well center operation with two "drilling pods" 30 assisted by a jack-up 10. As shown, the drilling pods 30 are placed on a separate platform 50 standing on its own legs 54 on the sea floor 18, such as a wellhead platform (wellhead spread). Several drilling pods 30, at least two, are placed on the drill floor 34 of the auxiliary wellhead platform 50, and can be skidded around for placement above a desired wellhead 42. A riser 44 can be placed between the BOP 36 and the wellhead 42. From the wellheads 42 several tubulars 56 runs down into the water and down into the sea floor 18. Umbilicals 58 and service loops runs from the main drilling unit 22 in order to provide the necessary power andUtilities from the main drilling unit to the distributed well centers on the wellhead platform 50. Fig. 4 is a typical layout of a drill floor 28 on a jack-up rig 10 capable of efficient tubular handling and offline stand building. As shown, in the upper left corner, is a driller's cabin/control station 60 connected to the equipment on the drill floor 28 on the cantilever 20, and connected by the umbilicals 58 to the equipment on the wellhead platform 50, for control and operations of the equipment and the drilling pods.

The drill floor 28 further is equipped with set back/racking area 62, and as shown with two racking machines 64 placed in front. Running longitudinal on the drill floor 28 are two rails 66 for catwalk machinery. Between the rails 66 is a main well center 68, to the right in the drawing, and an auxiliary stand building area 70, to the left in the drawing, each equipped with an iron roughneck 72. At the end of the rails, the drilling machine 26 of the main drilling unit 22 is shown.

Sequence of operation

The sequence of operation and distribution of tasks between the elevated drilling rig and the distributed well centers is set up so that any tripping activities or similar where there is a significant efficiency gain to have a tall derrick and large setback area is performed by the elevated main drilling rig. All slow progressing activities such as drilling ahead, milling, circulating and so on where there is little difference between a high spee and low spee unit can be carried out in the distributed well centers. A typical sequence is illustrated in figures 3 and 5. Initially the distributed well centers or drilling pods 30 are deployed from the main drilling unit 22 and rigged on the well deck. The operation proceeds by the main elevated drilling rig tripping in with bottom-hole assembly through a first drilling pod's 30 rotary bushing and BOP. When reaching TD the drill string is landed in the drilling pods rotary bushing and the iron roughneck machine on the drilling pod breaks the connection freeing the main well center 22 for other operations. The elevated drilling rig will then move over immediately to a position above the second drilling pod 30 to assist this while the first drilling pod 30 is drilling ahead using local pipe storage. The elevated drilling rig 22 will perform preparations for the next activity such as making up bottom hole assembly or rack up or down casing. The elevated drilling rig will trip in with the bottom hole assembly to TD through the second distributed well center. When reaching TD the string is landed out in the rotary bushing on the drilling pod and the iron roughneck breaks the connection releasing the drill string from the elevated drilling rig. The second drilling pod can then start drilling by use of its own local drill pipe storage. The elevated drilling rig will prepare the casing section for the first drilling pod, move over and when ready pull out the drill string from the first drilling pod and then run in the casing section through the drilling pods rotary bushing and BOP. When the run is close to completed, the casing landing string is transferred to the drilling pod, which can land out the casing.

By using this principle two or more wells can be drilled simultaneously from one main drilling unit by use of two or more distributed well centers keeping the well control for the well at all times. The size of the distributed well centers can be kept small as the main drilling unit is supplying services including mud, power, and hydraulics and so on. Furthermore the main drilling rig can be utilized to time optimize operations or operations requiring increased capabilities such as tripping in and out of the hole and running or pulling casings.

Claims

1. System for distributed well activities, comprising a main drilling unit (10) with a main drilling rig (22), a drill floor (28) equipped with one or more well centers (68,70), and one or more of set back/racking area (62), racking machines (64), catwalk machinery and iron roughnecks (72), said main drilling rig (22) is placed on a skiddable cantilever (20) with a drilling mast (24) and drilling machinery (26),characterized inthat a wellhead spread (50) is placed adjacent and below the cantilever (20) of the main drilling unit (10), said wellhead spread (50) comprises several drilling pods (30), where each drilling pod (30) has its own drilling equipment for performing drilling operations, and each drilling pod (30) is being arranged for simultaneously well operations in separate wells, while being supported by the main drilling unit (10).

2. System for distributed well activities according to claim 1, wherein the wellhead spread (50) comprises distributed well centers, such as drilling pods (30).

3. System for distributed well activities according to claim 1, wherein the main drilling unit (10) is a jack-up rig standing on support legs (14) and a with barge (12) that can be raised or lowered, the jack-up rig (10) is further equipped with the cantilever (20) with the main drilling rig (22), where the cantilever (20) can be driven or skidded out over water, such that the main drilling rig (22) is above an operational area to perform desired drilling operations.

4. System for distributed well activities according to claim 1, wherein the drilling pods (30) each comprises a mast (32), drill floor (34) and BOP (36), and in the mast (32) of the drilling pod (30) is a rotary drilling machine (38), which is adapted to drive a tubular (40) through the BOP (36) and into a desired wellhead (42).

5. System for distributed well activities according to claim 1, wherein the main drilling rig (22) comprises a driller's cabin/control station (60) connected by umbilicals (58) to the equipment on the wellhead spread (50), for control and operations of the drilling pods (30) and equipment on the wellhead spread (50).

6. System for distributed well activities according to claim 1, wherein the main drilling rig (22) is supporting the wellhead spread (50) with all main services, such as mud, power, hydraulics and similar.

7. Method for distributed well activities, comprising a main platform (10) with an elevated main drilling rig (22) with a drill floor (28) on a skiddable cantilever (20), equipped with several well centers (68,70),characterized in thata wellhead spread (50) is placed adjacent and below the cantilever (20) of the main drilling unit (10), wherein the method comprises the steps of: (a) deploying from the elevated main drilling unit (10) several drilling pods (30) on a well deck of the wellhead spread (50), (b) run well operations to a first well from the main well center (68) through a first drilling pod (30) on the wellhead spread (50), (c) break the connection between the main well center (68) and the first drilling pod (30), (d) proceed with drilling operations in the first well using the first drilling pod (30), (e) move the main drilling rig (22) to a position above a second drilling pod (30) on the wellhead spread (50), (f) run well operations to a second well from the main well center (68) through the second drilling pod (30) on the wellhead spread (50), (g) break the connection between the main well center (68) and the second drilling pod (30), and (h) proceed with well operations in the second well using the second drilling pod (30).

8. Method for distributed well activities according to claim 7, wherein the elevated drilling rig (22) performs preparations for the next activity, such as making up bottom hole assembly or rack up or down casing, while not supporting one of the drilling pods (30).

9. Method for distributed well activities according to claim 7, wherein the main elevated drilling rig (22) in step (b) is tripping in with bottom-hole assembly through the first drilling pod's (30) rotary bushing and BOP, and when reaching TD the drill string is landed in said drilling pods (30) rotary bushing and an iron roughneck machine on the drilling pod (30) breaks the connection freeing the main drilling rig (22) for other operations.

10. Method for distributed well activities according to claim 7, wherein the main drilling rig (22) moves over immediately to the second drilling pod (30), after breaking the connection between the main well center (68) and the first drilling pod (30), to assist the second drilling pod (30) while the first drilling pod is drilling ahead using local pipe storage.

11. Method for distributed well activities according to claim 7, wherein the elevated main drilling rig (22) in step (f) is tripping in with the bottom hole assembly to TD through the second drilling pod (30), and when reaching TD the string is landed out in the rotary bushing on the second drilling pod (30) and an iron roughneck breaks the connection releasing the drill string from the elevated main well center (68), while the second drilling pod (30) starts drilling by use of its own local drill pipe storage.

12. Method for distributed well activities according to claim 7, wherein the elevated drilling rig (22) prepares the casing section for the first drilling pod (30), moves over and when ready pulls out the drill string from the first drilling pod (30) and then run in the casing section through the drilling pod's rotary bushing and BOP.

13. Method for distributed well activities according to claim 12, wherein when the run is close to be completed, the casing landing string is transferred to the drilling pod (30) which is landing out the casing.