NL2023604B1 - Semi-submersible drilling vessel with a mud treatment and circulation system. - Google Patents
Semi-submersible drilling vessel with a mud treatment and circulation system. Download PDFInfo
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- NL2023604B1 NL2023604B1 NL2023604A NL2023604A NL2023604B1 NL 2023604 B1 NL2023604 B1 NL 2023604B1 NL 2023604 A NL2023604 A NL 2023604A NL 2023604 A NL2023604 A NL 2023604A NL 2023604 B1 NL2023604 B1 NL 2023604B1
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- Netherlands
- Prior art keywords
- mud
- vessel
- drilling
- pontoons
- semi
- Prior art date
Links
- 238000005553 drilling Methods 0.000 title claims abstract description 51
- 238000010304 firing Methods 0.000 claims abstract description 8
- 238000000034 method Methods 0.000 claims description 2
- PEDCQBHIVMGVHV-UHFFFAOYSA-N Glycerine Chemical compound OCC(O)CO PEDCQBHIVMGVHV-UHFFFAOYSA-N 0.000 claims 1
- 238000009434 installation Methods 0.000 abstract description 5
- 238000011144 upstream manufacturing Methods 0.000 description 6
- 238000005520 cutting process Methods 0.000 description 3
- 230000005484 gravity Effects 0.000 description 3
- 230000015572 biosynthetic process Effects 0.000 description 2
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 2
- 235000003934 Abelmoschus esculentus Nutrition 0.000 description 1
- 240000004507 Abelmoschus esculentus Species 0.000 description 1
- 239000000654 additive Substances 0.000 description 1
- TZCXTZWJZNENPQ-UHFFFAOYSA-L barium sulfate Chemical compound [Ba+2].[O-]S([O-])(=O)=O TZCXTZWJZNENPQ-UHFFFAOYSA-L 0.000 description 1
- 239000010428 baryte Substances 0.000 description 1
- 229910052601 baryte Inorganic materials 0.000 description 1
- 239000002199 base oil Substances 0.000 description 1
- 239000000440 bentonite Substances 0.000 description 1
- 229910000278 bentonite Inorganic materials 0.000 description 1
- SVPXDRXYRYOSEX-UHFFFAOYSA-N bentoquatam Chemical compound O.O=[Si]=O.O=[Al]O[Al]=O SVPXDRXYRYOSEX-UHFFFAOYSA-N 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 239000007788 liquid Substances 0.000 description 1
- 229920000136 polysorbate Polymers 0.000 description 1
- 238000005086 pumping Methods 0.000 description 1
- 239000004576 sand Substances 0.000 description 1
- 239000013535 sea water Substances 0.000 description 1
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B63—SHIPS OR OTHER WATERBORNE VESSELS; RELATED EQUIPMENT
- B63B—SHIPS OR OTHER WATERBORNE VESSELS; EQUIPMENT FOR SHIPPING
- B63B1/00—Hydrodynamic or hydrostatic features of hulls or of hydrofoils
- B63B1/02—Hydrodynamic or hydrostatic features of hulls or of hydrofoils deriving lift mainly from water displacement
- B63B1/10—Hydrodynamic or hydrostatic features of hulls or of hydrofoils deriving lift mainly from water displacement with multiple hulls
- B63B1/107—Semi-submersibles; Small waterline area multiple hull vessels and the like, e.g. SWATH
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B63—SHIPS OR OTHER WATERBORNE VESSELS; RELATED EQUIPMENT
- B63B—SHIPS OR OTHER WATERBORNE VESSELS; EQUIPMENT FOR SHIPPING
- B63B35/00—Vessels or similar floating structures specially adapted for specific purposes and not otherwise provided for
- B63B35/44—Floating buildings, stores, drilling platforms, or workshops, e.g. carrying water-oil separating devices
- B63B35/4413—Floating drilling platforms, e.g. carrying water-oil separating devices
-
- E—FIXED CONSTRUCTIONS
- E21—EARTH OR ROCK DRILLING; MINING
- E21B—EARTH OR ROCK DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
- E21B21/00—Methods or apparatus for flushing boreholes, e.g. by use of exhaust air from motor
- E21B21/01—Arrangements for handling drilling fluids or cuttings outside the borehole, e.g. mud boxes
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B63—SHIPS OR OTHER WATERBORNE VESSELS; RELATED EQUIPMENT
- B63B—SHIPS OR OTHER WATERBORNE VESSELS; EQUIPMENT FOR SHIPPING
- B63B1/00—Hydrodynamic or hydrostatic features of hulls or of hydrofoils
- B63B1/02—Hydrodynamic or hydrostatic features of hulls or of hydrofoils deriving lift mainly from water displacement
- B63B1/04—Hydrodynamic or hydrostatic features of hulls or of hydrofoils deriving lift mainly from water displacement with single hull
- B63B2001/044—Hydrodynamic or hydrostatic features of hulls or of hydrofoils deriving lift mainly from water displacement with single hull with a small waterline area compared to total displacement, e.g. of semi-submersible type
Landscapes
- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Chemical & Material Sciences (AREA)
- Physics & Mathematics (AREA)
- Life Sciences & Earth Sciences (AREA)
- Fluid Mechanics (AREA)
- Geology (AREA)
- Mining & Mineral Resources (AREA)
- Ocean & Marine Engineering (AREA)
- Combustion & Propulsion (AREA)
- Environmental & Geological Engineering (AREA)
- Geochemistry & Mineralogy (AREA)
- General Life Sciences & Earth Sciences (AREA)
- Architecture (AREA)
- Civil Engineering (AREA)
- Structural Engineering (AREA)
- Earth Drilling (AREA)
Abstract
A semi-submersible drilling vessel has a deckbox structure, one or more pontoons, e.g. two parallel pontoons or a ring pontoon, and has multiple support columns extending upward from the one or more pontoons and supporting thereon the deckbox structure. A moonpool extends through the deckbox structure. A drilling installation with a drilling tower is erected above the upper deck of the deckbox structure and is adapted to perform drilling operations along one or multiple firing lines through the moonpool involving a drill string. The vessel is provided with a mud treatment and circulation system, which comprises one or more active mud tanks from which drilling mud is supplied to the drill string. The one or more active mud tanks are arranged within the one or more pontoons of the vessel.
Description
P34202NL00 SEMI-SUBMERSIBLE DRILLING VESSEL WITH A MUD TREATMENT AND CIRCULATION SYSTEM.
The present invention relates to a semi-submersible drilling vessel. Such a vessel commonly has a deckbox structure, one or more pontoons, e.g. two parallel pontoons or a ring pontoon, and multiple support columns extending upward from the one or more pontoons and supporting thereon the deckbox structure.
The deckbox structure has an upper deck and a box bottom, with the box bottom being located at a height to provide an air gap between a highest wave crest and the box bottom of the deckbox structure. Herein the highest wave crest is related to sea conditions for the location and time of year where the vessel is operated.
The vessel also has a moonpool extending through the deckbox structure and a drilling installation with a drilling tower erected above the upper deck of the deckbox structure and adapted to perform drilling operations involving a drill string along one or multiple firing lines through the moonpool.
The vessel also has a mud treatment and circulation system further comprises active mud tanks from which drilling mud is supplied to the drill string, as well as reserve mud tanks, and other equipment, e.g. shaker devices, pumps, etc. The drilling mud is conventionally prepared on the vessel by mixing additives, such as barite and bentonite, to desalinated seawater, base oil or other liquids. During a drilling operation, the drilling mud is pumped from the active mud tank(s) to the drill bit in the well via the drill string. The drilling mud is then circulated back to the active mud tank(s) by flowing up in the annulus between the well bore/marine riser and the drill string, bringing drill cuttings removed from the formation by the drill bit along with it.
In known embodiments of the so-called flush deck design the semi-submersible vessel has a drill floor at the top end of the moonpool, wherein the drill floor is at the same level as the upper deck of the deckbox structure, e.g. allowing for (skid) rails to extend across the upper deck and continue on the drill floor for the transportation of drilling related equipment between a remote storage position and a position on the drill floor and/or aligned with the one or more firing lines.
2.
The present invention relates to the issue of incorporating the mud treatment and circulation system in the semi-submersible drilling vessel. Reference is made in this regard to the Andersson et al. document “Flush Drill Floor, A conceptual design that lowers the vertical center of gravity on semi-submersible offshore drilling rigs”, Chalmers University of Technology, Joakim Andersson & Mikael Ahlstedt, Göteborg, Sweden, 2014, Report No. E2014:019. URL: hitp://publications lib. chalmers se/records/fulitext/202824/202824 pdf As discussed in said Andersson et al. document the flush deck design places significant constraints on the layout of the mud treatment and circulation system as, compared to known designs where the drill floor is elevated above the upper deck, e.g. by some 10 meters, the available height within the deckbox structure is limited. Lowering the box bottom of the deckbox in order to increase height within the deckbox structure reduces the air gap, which reduces the operational window of the vessel. Keeping the box bottom at a certain height and raising the upper deck of the deckbox structure, and thus everything mounted on the upper deck, in order to increase the height within the deckbox structure significantly impacts the stability of the vessel.
Inthe Andersson et al. document the drilling installation comprises a diverter arranged in the moonpool below the drill floor. The diverter connects via a downward sloping mud return line to a mud treatment and circulation system. Within the deckbox structure, adjacent the moonpool, there is a shaker room and the mud passes by gravity via the downward sloping mud return line from the diverter to the shaker room. In the shaker room there are provided: - one or more shale shaker devices, - one or more upstream mud tanks arranged to receive gas cut mud from the one or more shale shaker devices, e.g. one or more sand trap tanks, - a vacuum degasser having an inlet pipe extending into an upstream mud tank, a vacuum tank, a vacuum pump, and an outlet, and - adegassed mud tank receiving degassed mud from the outlet of the vacuum degasser. The mud treatment and circulation system further comprises, within the deckbox structure: - one or more active mud tanks, - one or more mud pumps having inlets connected to the one or more active mud tanks.
As part of the flush deck design in the Andersson et al. document the upper deck of the deckbox structure, at least the portion thereof above the shaker room and the active mud tanks, is at the same level as the drill floor.
-3- In order to fit the mud treatment and circulation system Andersson et al. mentions a number of design choices which include placing the tanks of the system either on the lower deck of the deck box or even directly on the box bottom, and includes providing a low depth design of the upstream tanks, degassed mud receiving tank, and active mud tanks. As a result of the shallow design of the tanks, including the active tanks, in Andersson et al. the floor area occupied by the system is significantly greater than in non-flush deck vessel designs where more height is available to accommodate the mud treatment and circulation system.
In WO2018/1644572 a semi-submersible vessel is disclosed, wherein the degassed mud tank receiving degassed mud from the vacuum degasser has an effective height between the bottom thereof to the operational mud level in the degassed mud tank that is greater than the corresponding effective height of the one or more upstream mud tanks. The degassed mud tank is mounted so that, in operation, the operational mud level in the degassed mud tank is atleast 1.5 meter, preferably at least 2 meters, e.g. between 2 and 3 meters, higher than in the one or more upstream tanks with the vacuum degassers self-suction effect causing the mud to be pumped from the upstream tank, via the vacuum degasser, into the degassed mud tank. This arrangement allows for a flush deck design to be combined with an optimal air gap of the deckbox structure and with an optimal use of floor area occupied by the mud treatment system.
In WO2015/039667 a semi-submersible vessel is disclosed, wherein the active mud tanks are arranged within the deckbox structure, in the vicinity of the moonpool. The document discusses converting water ballast tanks in the pontoons of the vessel into reserve mud tanks, also called mud holding tanks. Dedicated piping and one or more pumps, serve to transfer drilling mud between the mud holding tank in the pontoon and the active mud tanks in the deckbox structure.
The present invention aims to provide an improved semi-submersible vessel, in particular with respect to the mud treatment and circulation system thereof.
According to the invention a semi-submersible drilling vessel is provided as described in claim 1.
Inthe inventive semi-submersible drilling, the multiple active mud tanks, preferably all active mud tanks of the vessel, are arranged within the one or more pontoons of the vessel. As explained, in existing vessels the one or more active mud tanks are arranged within the
4- deckbox. So the invention proposes to move these active mud tanks to a location within the one or more pontoons. Preferably, one or more reserve mud tanks, or mud holding tanks, are also arranged within the one or more pontoons of the vessel.
The vessel will have one or more pumps and related piping configured to move the drilling mud from these low-mounted active mud tanks to the drill string during a drilling operation wherein the mud is circulated.
In an embodiment, the vessel is provided with a shaker room within the deckbox structure and in proximity of, e.g. adjacent, the moonpool, e.g. on the lower deck of the deckbox structure. A mud return line, e.g. a downward sloping mud return line, is provided that passes mud from the annulus between the drill string and the riser to the shaker room, wherein the mud treatment and circulation system comprises, in said shaker room, one or more shale shaker devices.
In an embodiment, the upper deck of the deckbox structure, e.g. at least the portion thereof above the shaker room, is at the same level as a drill floor of the vessel. The invention also relates to a method for drilling a subsea wellbore wherein use is made of semi-submersible drilling vessel as disclosed herein. The invention will now be explained with reference to the drawings. In the drawings: Fig. 1 shows schematically an example of a semi-submersible drilling vessel of the invention, Fig. 2 shows schematically a cross-section of the deckbox structure of the semi-submersible drilling vessel of figure 1, Fig. 3 shows schematically the layout of a pontoon of a semi-submersible drilling vessel of the invention, Fig. 4 shows schematically the layout of the other pontoon of a semi-submersible drilling vessel of the invention, Fig. 5 shows the cross-section V-V in figure 3, Fig. 6 shows the cross-section VI-VI in figure 4.
-5- As is commonly known a semi-submersible drilling vessel 1 has a deckbox structure 2 that is supported via multiple buoyant columns 3 on one or more buoyant pontoons 4a,b, e.g. two parallel pontoons or a ring pontoon. The columns 3 extend upward from the one or more pontoons 4a, b and support thereon the deckbox structure 2.
The deckbox structure 2 has an upper deck 5, a lower deck 6, and possibly one or more tween decks. A main deckbox bottom 7 extends underneath the lower deck. For example, in practical embodiments, the vertical spacing between the upper deck 5 and the main box bottom 7 of the deckbox structure is between 8.5 and 11 meters. In the total design of the vessel, the bottom 7 is located at a height that provides an air gap between a predicted highest wave crest and the bottom 7 of the deckbox structure 2. The figures show part of a moonpool 15 that extends vertically through the deckbox structure
2. The vessel comprises a drilling installation with a drilling tower 20, e.g. a derrick over the moonpool or a mast 20 having an associated drawworks with a firing line 25 along an outer contour of the mast. The drilling tower 20 is erected above the upper deck 5 of the deckbox structure 2. The drilling installation is adapted to perform drilling operations along one or multiple firing lines 25 through the moonpool 15. The figures depict a drill floor 17 at the top end of the moonpool 15, and flush with the adjacent upper deck 5 of the deckbox structure 2. For example, as depicted here, one or more rails 18 extend over the upper deck 5 onto the drill floor 17, e.g. for transportation of drilling equipment onto the drill floor, e.g. into the firing line 25. For example, the transportation is done by skidding, using skiddable transporters.
In embodiments the drill floor 17 is mobile, e.g. vertically mobile, tiltable, or slidable in a horizontal plane, e.g. to allow for the passage of large items, e.g. a BOP into and out of the moonpool 15. For example, in an embodiment, the drill floor 17 is mounted on a set of vertically arranged hydraulic cylinders that allow for vertical motion of the drill floor between a lower position, flush with the upper deck 5, and an elevated position, e.g. the latter allowing for passage of a
-B- tall BOP between a storage position thereof and a position aligned with a firing line, so underneath the elevated drill floor. In an embodiment, drilling is done with the drill floor stationary in its lower position. In yet another embodiment, the hydraulic cylinders are embodied to allow the drill floor to perform a heave compensation motion relative to the deckbox structure. The vessel 1 is provided with a mud treatment and circulation system. The figures schematically show a shaker room 40 near to the moonpool 15. This shaker room 40 is provided in the deckbox structure, and the upper deck 5 above this shaker room 40 is flush with the drill floor 17. A downward sloping mud return line 30 is provided that passes, by gravity, mud from the annulus between the drill string and the riser to the shaker room 40.
In the shaker room 40 a distributor is provided for the mud emerging from the line 30, which distributor distributes the mud to be treated to multiple shale shaker devices 43, 44, 45. The deckbox structure 2 can accommodate more equipment involved in the mud circulation, for example a vacuum degasser, a centrifuge, a drill cuttings handling station, a gumbo box, a mud control system, etc. As shown in figures 3 — 6 the vessel 1 has the one or more active mud tanks 60 of the mud circulation system arranged within the pontoons 4a, b of the vessel.
Figure 2 shows riser 70 through which drill string 19 extends. During a drilling operation, the drilling mud is pumped from the active mud tanks 60 to the drill bit in the well via the drill string 19. The drilling mud is then circulated back to the active mud tanks by flowing up in the annulus between the riser 70 and the drill string 19, bringing drill cuttings removed from the formation by the drill bit along with it. This mud is then passed through the shaker room 40 and treated by related equipment, before being returned to the active mud tanks 60, from which drilling mud is supplied to the drill string 19 again via piping 61 and related pumping devices.
The one or more active mud tanks 80 are arranged within the one or more pontoons 4a, b of the vessel.
-7- It is shown here, that a number of active mud tanks 60 are mounted in one pontoon 4a, and other active mud tanks 60 in the other pontoon 4b.
In addition to the active mud tanks 60 being arranged within the one or more pontoons 4a, b, also reserve mud tanks 80 are arranged within the one or more pontoons 4a, b.
It is shown that the mud tanks 60, 80 are arranged along an inner side of the elongated pontoons 4a, b in this twin-pontoon vessel 1. A hallway 90 for access by personnel extends over the length of the elongated pontoon 4a, b, along the linear array of mud tanks 60, 80. Underneath the mud tanks 60, 80 ballast water tanks are provided.
Claims (4)
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| NL2023604A NL2023604B1 (en) | 2019-08-02 | 2019-08-02 | Semi-submersible drilling vessel with a mud treatment and circulation system. |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| NL2023604A NL2023604B1 (en) | 2019-08-02 | 2019-08-02 | Semi-submersible drilling vessel with a mud treatment and circulation system. |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| NL2023604B1 true NL2023604B1 (en) | 2021-02-23 |
Family
ID=68073131
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| NL2023604A NL2023604B1 (en) | 2019-08-02 | 2019-08-02 | Semi-submersible drilling vessel with a mud treatment and circulation system. |
Country Status (1)
| Country | Link |
|---|---|
| NL (1) | NL2023604B1 (en) |
Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3874314A (en) * | 1973-06-29 | 1975-04-01 | John P Sanders | Method of constructing submersible structures utilizing submarine hulls |
| US4102288A (en) * | 1977-02-28 | 1978-07-25 | Sun Oil Company Limited | Operations vessel for ice covered seas |
| GB2310634A (en) * | 1996-02-27 | 1997-09-03 | Mp | Semi-Submersible Vessels |
| WO1999025608A1 (en) * | 1997-11-15 | 1999-05-27 | Sofitech N.V. | Ballasting of semi-submersible rig |
| WO2015039667A2 (en) | 2013-09-23 | 2015-03-26 | Semco Maritime A/S | A floating offshore rig for drilling in a hydrocarbons containing formation and having a converted ballasting tank, and a method of operating the same |
| WO2016124011A1 (en) * | 2015-02-02 | 2016-08-11 | 中集海洋工程研究院有限公司 | Middle depth water semi-submersible type drilling platform |
| WO2018164572A1 (en) | 2017-03-06 | 2018-09-13 | Itrec B.V. | Semi-submersible drilling vessel with a mud treatment and circulation system |
-
2019
- 2019-08-02 NL NL2023604A patent/NL2023604B1/en active
Patent Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3874314A (en) * | 1973-06-29 | 1975-04-01 | John P Sanders | Method of constructing submersible structures utilizing submarine hulls |
| US4102288A (en) * | 1977-02-28 | 1978-07-25 | Sun Oil Company Limited | Operations vessel for ice covered seas |
| GB2310634A (en) * | 1996-02-27 | 1997-09-03 | Mp | Semi-Submersible Vessels |
| WO1999025608A1 (en) * | 1997-11-15 | 1999-05-27 | Sofitech N.V. | Ballasting of semi-submersible rig |
| WO2015039667A2 (en) | 2013-09-23 | 2015-03-26 | Semco Maritime A/S | A floating offshore rig for drilling in a hydrocarbons containing formation and having a converted ballasting tank, and a method of operating the same |
| WO2016124011A1 (en) * | 2015-02-02 | 2016-08-11 | 中集海洋工程研究院有限公司 | Middle depth water semi-submersible type drilling platform |
| WO2018164572A1 (en) | 2017-03-06 | 2018-09-13 | Itrec B.V. | Semi-submersible drilling vessel with a mud treatment and circulation system |
Non-Patent Citations (1)
| Title |
|---|
| ANDERSSON ET AL.: "Flush Drill Floor, A conceptual design that lowers the vertical center of gravity on semi-submersible offshore drilling rigs", 2014, CHALMERS UNIVERSITY OF TECHNOLOGY, JOAKIM ANDERSSON & MIKAEL AHLSTEDT |
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