US20010041098A1 - Emergency dump apparatus for buoyancy air tanks on buoyant riser systems - Google Patents
Emergency dump apparatus for buoyancy air tanks on buoyant riser systems Download PDFInfo
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- US20010041098A1 US20010041098A1 US09/915,011 US91501101A US2001041098A1 US 20010041098 A1 US20010041098 A1 US 20010041098A1 US 91501101 A US91501101 A US 91501101A US 2001041098 A1 US2001041098 A1 US 2001041098A1
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- riser
- buoyancy tank
- buoyancy
- housings
- housing
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- 239000002360 explosive Substances 0.000 claims description 14
- 238000007789 sealing Methods 0.000 claims description 4
- 230000003213 activating effect Effects 0.000 claims 1
- 238000005553 drilling Methods 0.000 abstract description 14
- 238000013022 venting Methods 0.000 abstract description 13
- 238000009877 rendering Methods 0.000 abstract description 6
- 230000001174 ascending effect Effects 0.000 abstract description 2
- 230000002028 premature Effects 0.000 abstract 1
- 230000000452 restraining effect Effects 0.000 description 12
- 230000000712 assembly Effects 0.000 description 7
- 238000000429 assembly Methods 0.000 description 7
- 230000004913 activation Effects 0.000 description 4
- 230000000717 retained effect Effects 0.000 description 3
- 230000004075 alteration Effects 0.000 description 2
- 231100001261 hazardous Toxicity 0.000 description 2
- 238000000034 method Methods 0.000 description 2
- 238000012986 modification Methods 0.000 description 2
- 230000004048 modification Effects 0.000 description 2
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 2
- 238000001514 detection method Methods 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 229920000728 polyester Polymers 0.000 description 1
- 239000013535 sea water Substances 0.000 description 1
- 239000000725 suspension Substances 0.000 description 1
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Classifications
-
- 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
- E21B17/00—Drilling rods or pipes; Flexible drill strings; Kellies; Drill collars; Sucker rods; Cables; Casings; Tubings
- E21B17/01—Risers
- E21B17/012—Risers with buoyancy elements
Definitions
- This invention relates to a novel apparatus for quickly releasing the air from buoyancy tanks or housings in those situations when a quick deballasting of the buoyancy tanks or housings is required.
- a typical situation where this might occur is the case of a free-standing drilling riser that replaces most of the rig tension with positive buoyancy provided by buoyancy tanks or housings mounted on the riser sections.
- the positively buoyant riser sections with attached buoyancy tanks or housings would ascend to the surface with increasing velocity to impact the drilling rig's or ship's hull with sufficient force to seriously damage the drilling rig.
- the impact of the riser and buoyancy tank or buoyancy housing could sufficiently damage the drilling rig or ship to cause it to sink and lives to be lost.
- buoyancy tanks or housings provide the buoyancy
- the buoyancy tanks or housings are usually constructed with an open lower end to facilitate filling of the buoyancy tanks or housings by compressed air or other suitable gas. The volume and pressure of the supplied compressed air is determined by the water depth in which the buoyancy tanks or housings are to be used.
- Various methods of filling the buoyancy tank or housings either individually or in groups are well known to those of ordinary skill in the art.
- the present invention has particular applicability.
- the riser should fail as noted above, a particularly hazardous situation is presented by the positively buoyant tanks or housings.
- the present invention minimizes this hazardous situation by allowing a means to vent or deballast the buoyancy tank or housings in a few seconds. It is the rapid venting or deballasting of these buoyancy tanks or housings to which the present invention most closely applies.
- a marine riser with open bottom air cans is shown in U.S. Pat. No. 4,099,560 (Fischer et al.)
- the apparatus shown by Fischer et al. discloses an air dump valve attached to a tether line that is activated in the event of the riser parting.
- U.S. Pat. No. 4,176,986 to Taft et al. discloses another type of riser system with buoyancy tanks attached. A dump valve for rapidly venting the compressed air and controlled by a pilot valve assembly is shown.
- U.S. Pat. No. 4,646,840 to Bartholomew et al. owned by the assignee of the current invention, discloses a buoyancy tank or housing system with a cascading system for supplying air to the buoyancy tank or housings.
- the current invention uses a frangible joint or connection to allow for rapid venting of the compressed air and deballasting of a buoyancy tank or housing in a positively buoyant riser system in the event of a riser section parting.
- the rapid venting of the compressed air ensures that the riser section cannot rapidly ascend to the surface and damage the drill rig positioned above.
- the buoyancy tank or housing in a first embodiment of the invention, includes a circumferentially shaped channel positioned on its upper face.
- An annularly shaped cover plate is placed over the circumferentially shaped channel and sealed in place by a frangible weld.
- the annularly shaped cover plate includes a ring positioned on its lower face to which a tether line is anchored.
- the tether line extends downwardly to similarly positioned rings on the subsequent riser sections and buoyancy tanks or housings.
- the tether line extends from the lowermost buoyancy tank or housing and is anchored on the BOP stack below.
- the buoyancy tank or housing includes an annularly shaped flange positioned on the top.
- the annularly shaped flange has a weld joint on its interior and a seal on its exterior to seal against the riser sections and buoyancy tank or housing, respectively.
- the flange is retained by a plurality of toggle retainer clamps.
- the toggle retainer clamps are connected to a tether line that extends from the lowermost buoyancy tank or housing and is anchored on the BOP stack below.
- the buoyancy tank or housing includes an annularly shaped flange positioned on the top.
- the annularly shaped flange has a weld joint on its interior and a seal on its exterior to seal against the riser sections and buoyancy tank or housing, respectively.
- the flange is retained by a plurality of retainer pin assemblies.
- the retainer pin assemblies are connected to a tether line that extends from the lowermost buoyancy tank or housing and is anchored on the BOP stack below. In the event of a catastrophic parting of the riser, the parting of the riser causes the tether line to release removable retainer pins thereby releasing the annularly shaped flange from the buoyancy tank or housing. This causes an immediate and complete venting of the buoyancy tanks or housings, rendering them negatively buoyant.
- the buoyancy tank or housing includes an annularly shaped flange positioned on the top.
- the annularly shaped flange has a weld joint on its interior and a seal on its exterior to seal against the riser sections and buoyancy tank or housing, respectively.
- the flange is retained by a plurality of explosive bolt assemblies.
- the explosive bolt assemblies are connected to a transceiver box connected to the explosive bolt assemblies. In the event of a catastrophic parting of the riser, a signal is transmitted to the transceiver box that in turns fires the explosive bolt assemblies.
- the release of the explosive bolt assemblies allows the annularly shaped flange to be released from the buoyancy tank or housing. This causes an immediate and complete venting of the buoyancy tanks or housings, rendering them negatively buoyant.
- a principal object of the present invention is to provide an apparatus to quickly vent the air from buoyancy tanks or housings thereby preventing their uncontrolled and rapid ascension to the surface.
- Another object of the present invention is to provide an apparatus to quickly vent the air from buoyancy tanks or housings without requiring any operator intervention in the event the riser parts.
- FIG. 1 is an elevation view of a riser system with buoyancy tank or housings used in subsea oil and gas drilling operations that incorporates the emergency dump apparatus of the present invention
- FIG. 2 is an isometric view of the first embodiment of the emergency dump apparatus prior to being activated.
- FIG. 3 is an isometric view of the first embodiment of the emergency dump apparatus after activation.
- FIG. 4 is a sectional view of the second embodiment of the emergency dump apparatus prior to being activated.
- FIG. 5 is a sectional view of the second embodiment of the emergency dump apparatus after activation.
- FIG. 6 is a sectional view of the third embodiment of the emergency dump apparatus prior to being activated.
- FIG. 7 is a sectional view of the third embodiment of the emergency dump apparatus after activation.
- FIG. 8 is a sectional view of the fourth embodiment of the emergency dump apparatus prior to being activated.
- FIG. 9 is a sectional view of the fourth embodiment of the emergency dump apparatus after activation.
- Subsea drilling riser system 100 is shown in an elevation view.
- Subsea drilling riser system 100 extends from floating drilling rig or vessel 102 to BOP stack 104 located on ocean floor 106 .
- Subsea drilling riser system 100 is composed of a plurality of riser sections 108 connected in end to end relationship by suitable mechanical means as end connections 110 which may be threaded connections, flanged end connections or clamp hub connections as is well known to those of ordinary skill in the art.
- Some of riser sections 108 have buoyancy tank or housings 112 clamped thereon or they may be integrally formed therewith without departing from the scope of the invention.
- Buoyancy tank or housings 112 air filled with compressed air to provide buoyancy to subsea drilling riser system 100 thereby lessening or obviating the need for a riser tensioner system.
- Upper riser connector 114 is provided near the upper end of riser system 100 to allow drilling rig 102 to disconnect from riser system 100 in the event of a drive off or inclement weather that necessitates the suspension of drilling operations.
- Tether line 116 of suitable material as chain, wire or polyester rope, extends from buoyancy tank or housings 112 to BOP stack 104 below the lower marine riser package where it is anchored for purposes that will be explained hereinafter.
- the first embodiment of the present invention includes buoyancy tank or housing 210 attached to riser section 108 .
- Buoyancy tank or housing 210 includes frangible section 212 to which actuation ring 214 is attached.
- Tether line 116 is connected to actuation ring 214 and extends downwardly to BOP stack 104 as previously noted.
- Frangible section 212 includes circumferentially shaped channel 216 in buoyancy tank or housing 210 that is sealed by annularly shaped ring 218 .
- Annularly shaped ring 218 is sealed by frangible welded joint 220 .
- Annularly shaped ring 218 extends circumferentially around buoyancy tank or housing 210 and is sealed completely around its periphery by frangible welded joint 220 .
- Frangible welded joint 220 is sized to break when a suitable predetermined force is applied by tether line 116 .
- Restraining line 222 extends between buoyancy tank or housing 210 and riser section 108 and connects to restraining hoops 224 that are welded to buoyancy tank 210 and riser section 108 .
- buoyancy tank or housings 210 In the event of a catastrophic riser failure, i.e., where the riser below the buoyancy tanks or housings has parted, the positively buoyant riser sections 108 with attached buoyancy tank or housings 210 will ascend to the surface with increasing velocity unless the compressed air in buoyancy tank or housings 210 is vented immediately. As positively buoyant riser sections 108 with attached buoyancy tank or housings 210 start to ascend toward the surface, tether line 116 is drawn taut and begins pulling on actuation ring 214 . As best seen in FIG. 3, continued ascent of riser sections 108 with attached buoyancy tank or housings 210 causes frangible welded joint 220 to break and peel annularly shaped ring 218 from buoyancy tank or housings 210 .
- FIGS. 4 and 5 A second embodiment of the present invention is shown in FIGS. 4 and 5. Those items that are the same as in the first embodiment retain the same numeric designation.
- riser section 108 has buoyancy tank or housing 310 attached thereto.
- Buoyancy tank or housing 310 has toggle clamp assembly 312 positioned at its upper end to which actuation arm 314 is attached.
- Tether line 116 is connected to actuation arm 314 and extends downwardly to BOP stack 104 as previously noted.
- Toggle clamp assembly 312 holds toggle retainer clamps 322 in engagement retaining annularly shaped flange 316 that seals inside the top of buoyancy tank or housing 310 with an annular seal ring 320 .
- Annularly shaped flange 316 is attached and sealed against riser section 108 by welds 318 .
- Rapidly removable section such as annularly shaped flange 316 is held by in sealing engagement with buoyancy tank or housing 310 by toggle retainer clamps 322 .
- Toggle retainer clamps 322 include a frangible retainer pin 324 .
- Frangible retainer pin 324 is sized to break when a suitable predetermined force is applied by tether line 116 .
- Restraining line 326 extends between buoyancy tank or housing 310 and riser section 108 and connects to restraining hoops 328 that are welded to buoyancy tank 310 and riser section 108 .
- FIGS. 6 and 7. A third embodiment of the present invention is shown in FIGS. 6 and 7. Those items that are the same as in the first embodiment retain the same numeric designation.
- riser section 108 has buoyancy tank or housing 410 attached thereto.
- Buoyancy tank or housing 410 has retainer pin assembly 412 positioned at its upper end to which actuation arm 414 is attached.
- Tether line 116 is connected to actuation arm 414 and extends downwardly to BOP stack 104 as previously noted.
- Retainer pin assembly 412 holds retainer arm 416 in engagement retaining annularly shaped flange 418 that seals inside the top of buoyancy tank or housing 410 with an annular seal ring 420 .
- Rapidly removable section such as annularly shaped flange 418 is attached and sealed against riser section 108 by welds 422 .
- Annularly shaped flange 418 is held by in sealing engagement with buoyancy tank or housing 410 by retainer arm 416 .
- Retainer arm 416 is held in position by retainer pin assembly 412 that includes removable retainer pin 424 .
- Removable retainer pin 424 is released when a suitable predetermined force is applied by tether line 116 to actuation arm 414 and pivoting retainer pin assembly 412 outwardly.
- Restraining line 426 extends between buoyancy tank or housing 410 and riser section 108 and connects to restraining hoops 428 that are welded to buoyancy tank 410 and riser section 108 .
- FIGS. 8 and 9 A fourth embodiment of the present invention is shown in FIGS. 8 and 9. Those items that are the same as in the first embodiment retain the same numeric designation.
- riser section 108 has buoyancy tank or housing 510 attached thereto.
- Buoyancy tank or housing 510 has explosive bolt assembly 512 positioned at its upper end.
- a sensing means such as transceiver box 514 is attached to buoyancy tank or housing adjacent explosive bolt assembly 512 .
- Control lead 516 connects transceiver box 514 to a remote releasing means such as explosive bolt assembly 512 .
- Explosive bolt assembly 512 retains annularly shaped flange 518 that seals inside the top of buoyancy tank or housing 510 with an annular seal ring 520 .
- Annularly shaped flange 518 is attached and sealed against riser section 108 by welds 522 .
- Rapidly removable section such as annularly shaped flange 518 is held in sealing engagement with buoyancy tank or housing 510 by explosive bolt assembly 512 .
- Explosive bolt assembly 512 is activated when upon detection of a parting of the riser a signal is sent to a sensing means such as transceiver box 514 .
- a sensing means such as transceiver box 514 .
- Restraining line 524 extends between buoyancy tank or housing 510 and riser section 108 and connects to restraining hoops 526 that are welded to buoyancy tank 510 and riser section 108 .
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Abstract
An apparatus for rapid venting of the compressed air and deballasting of a buoyant air tank in a positively buoyant riser system in the event of a premature drive off or a riser section parting is shown. The rapid venting of the compressed air ensures that the riser section cannot rapidly ascend to the surface and damage the drilling rig positioned above. In a first embodiment, the buoyancy tank or housing includes a circumferentially shaped channel positioned on its upper end. An annularly shaped ring is placed over the circumferentially shaped channel and sealed in place by a frangible weld. A tether line attaches to the annularly shaped ring and extends to an anchor point on the BOP stack below. In the event of a catastrophic parting of the riser, as the riser sections and attached buoyancy tank or housings begin ascending, the tether line is drawn tight. Further ascension of the buoyancy tank or housings, causes the frangible weld joints to break and peel back the annularly shaped ring, exposing the circumferentially shaped channel. This causes an immediate and complete venting of the buoyancy tank or housings, rendering them negatively buoyant. Alternate embodiments using an annularly shaped flange releasable by toggle clamps or retainer pins are also shown.
Description
- This is a divisional application of application Ser. No. 09/753,348 filed Jan. 2, 2001, hereby incorporated herein by reference; which is a divisional application of application Ser. No. 09/339,630 filed Jun. 24, 1999, now U.S. Pat. No. 6,193,441, hereby incorporated herein by reference.
- 1. Field of the Invention
- This invention relates to a novel apparatus for quickly releasing the air from buoyancy tanks or housings in those situations when a quick deballasting of the buoyancy tanks or housings is required. A typical situation where this might occur is the case of a free-standing drilling riser that replaces most of the rig tension with positive buoyancy provided by buoyancy tanks or housings mounted on the riser sections. In the event of a catastrophic riser failure, i.e., where the riser below the buoyancy tanks or housings has parted or a bottom release in a dynamically positioned vessel drive off, the positively buoyant riser sections with attached buoyancy tanks or housings would ascend to the surface with increasing velocity to impact the drilling rig's or ship's hull with sufficient force to seriously damage the drilling rig. In the extreme case, the impact of the riser and buoyancy tank or buoyancy housing could sufficiently damage the drilling rig or ship to cause it to sink and lives to be lost.
- The use of such positively buoyant risers with buoyancy tanks or housings providing the buoyancy is well known to those of ordinary skill in the art. Typical use dictates several riser sections will have buoyancy tanks or housings attached, depending on the water depth, to leave the riser disconnected and free standing or at least minimize the load on the rig's tensioner system while connected. The buoyancy tanks or housings are usually constructed with an open lower end to facilitate filling of the buoyancy tanks or housings by compressed air or other suitable gas. The volume and pressure of the supplied compressed air is determined by the water depth in which the buoyancy tanks or housings are to be used. Various methods of filling the buoyancy tank or housings either individually or in groups are well known to those of ordinary skill in the art.
- Once the riser sections with attached buoyancy tanks or housings are in place the present invention has particular applicability. In the event the riser should fail as noted above, a particularly hazardous situation is presented by the positively buoyant tanks or housings. The present invention minimizes this hazardous situation by allowing a means to vent or deballast the buoyancy tank or housings in a few seconds. It is the rapid venting or deballasting of these buoyancy tanks or housings to which the present invention most closely applies.
- 2. Description of Related Art
- A marine riser with open bottom air cans is shown in U.S. Pat. No. 4,099,560 (Fischer et al.) The apparatus shown by Fischer et al. discloses an air dump valve attached to a tether line that is activated in the event of the riser parting.
- U.S. Pat. No. 4,176,986 to Taft et al. discloses another type of riser system with buoyancy tanks attached. A dump valve for rapidly venting the compressed air and controlled by a pilot valve assembly is shown.
- Another marine riser with buoyancy system is disclosed in U.S. Pat. No. 4,422,801 (Hale et al.) The system shown by Hale et al. uses a quarter turn ball valve actuated by a trigger cable and air cylinder to vent the buoyancy air tanks.
- U.S. Pat. No. 4,646,840 to Bartholomew et al., owned by the assignee of the current invention, discloses a buoyancy tank or housing system with a cascading system for supplying air to the buoyancy tank or housings.
- All these systems are too slow for a dynamically positioned vessel that must vent in less than thirty seconds to avoid damage to the drilling vessel.
- The current invention uses a frangible joint or connection to allow for rapid venting of the compressed air and deballasting of a buoyancy tank or housing in a positively buoyant riser system in the event of a riser section parting. The rapid venting of the compressed air ensures that the riser section cannot rapidly ascend to the surface and damage the drill rig positioned above.
- According to the present invention, in a first embodiment of the invention, the buoyancy tank or housing includes a circumferentially shaped channel positioned on its upper face. An annularly shaped cover plate is placed over the circumferentially shaped channel and sealed in place by a frangible weld. The annularly shaped cover plate includes a ring positioned on its lower face to which a tether line is anchored. The tether line extends downwardly to similarly positioned rings on the subsequent riser sections and buoyancy tanks or housings. The tether line extends from the lowermost buoyancy tank or housing and is anchored on the BOP stack below. In the event of a catastrophic parting of the riser, as the riser sections and attached buoyancy tanks or housings begin ascending, the tether line is drawn tight. Further ascension of the buoyancy tanks or housings, causes the frangible weld joints to break and peel back the cover plate, exposing the circumferentially shaped channels. This causes an immediate and complete venting of the buoyancy tanks or housings, rendering them negatively buoyant.
- In a second embodiment of the invention, the buoyancy tank or housing includes an annularly shaped flange positioned on the top. The annularly shaped flange has a weld joint on its interior and a seal on its exterior to seal against the riser sections and buoyancy tank or housing, respectively. The flange is retained by a plurality of toggle retainer clamps. The toggle retainer clamps are connected to a tether line that extends from the lowermost buoyancy tank or housing and is anchored on the BOP stack below. In the event of a catastrophic parting of the riser, the parting of the riser causes the tether line to release frangible retainer pins holding the toggle retainer clamps thereby releasing the annularly shaped flange from the buoyancy housing. This causes an immediate and complete venting of the buoyancy tanks or housings, rendering them negatively buoyant.
- In a third embodiment of the invention, the buoyancy tank or housing includes an annularly shaped flange positioned on the top. The annularly shaped flange has a weld joint on its interior and a seal on its exterior to seal against the riser sections and buoyancy tank or housing, respectively. The flange is retained by a plurality of retainer pin assemblies. The retainer pin assemblies are connected to a tether line that extends from the lowermost buoyancy tank or housing and is anchored on the BOP stack below. In the event of a catastrophic parting of the riser, the parting of the riser causes the tether line to release removable retainer pins thereby releasing the annularly shaped flange from the buoyancy tank or housing. This causes an immediate and complete venting of the buoyancy tanks or housings, rendering them negatively buoyant.
- In a fourth embodiment of the invention, the buoyancy tank or housing includes an annularly shaped flange positioned on the top. The annularly shaped flange has a weld joint on its interior and a seal on its exterior to seal against the riser sections and buoyancy tank or housing, respectively. The flange is retained by a plurality of explosive bolt assemblies. The explosive bolt assemblies are connected to a transceiver box connected to the explosive bolt assemblies. In the event of a catastrophic parting of the riser, a signal is transmitted to the transceiver box that in turns fires the explosive bolt assemblies. The release of the explosive bolt assemblies allows the annularly shaped flange to be released from the buoyancy tank or housing. This causes an immediate and complete venting of the buoyancy tanks or housings, rendering them negatively buoyant.
- A principal object of the present invention is to provide an apparatus to quickly vent the air from buoyancy tanks or housings thereby preventing their uncontrolled and rapid ascension to the surface.
- Another object of the present invention is to provide an apparatus to quickly vent the air from buoyancy tanks or housings without requiring any operator intervention in the event the riser parts.
- These with other objects and advantages of the present invention are pointed out with specificness in the claims annexed hereto and form a part of this disclosure. A full and complete understanding of the invention may be had by reference to the accompanying drawings and description of the preferred embodiments.
- These and other objects and advantages of the present invention are set forth below and further made clear by reference to the drawings, wherein:
- FIG. 1 is an elevation view of a riser system with buoyancy tank or housings used in subsea oil and gas drilling operations that incorporates the emergency dump apparatus of the present invention
- FIG. 2 is an isometric view of the first embodiment of the emergency dump apparatus prior to being activated.
- FIG. 3 is an isometric view of the first embodiment of the emergency dump apparatus after activation.
- FIG. 4 is a sectional view of the second embodiment of the emergency dump apparatus prior to being activated.
- FIG. 5 is a sectional view of the second embodiment of the emergency dump apparatus after activation.
- FIG. 6 is a sectional view of the third embodiment of the emergency dump apparatus prior to being activated.
- FIG. 7 is a sectional view of the third embodiment of the emergency dump apparatus after activation.
- FIG. 8 is a sectional view of the fourth embodiment of the emergency dump apparatus prior to being activated.
- FIG. 9 is a sectional view of the fourth embodiment of the emergency dump apparatus after activation.
- With reference to the drawings, and particularly to FIG. 1, subsea
drilling riser system 100 is shown in an elevation view. Subseadrilling riser system 100 extends from floating drilling rig orvessel 102 to BOP stack 104 located onocean floor 106. Subseadrilling riser system 100 is composed of a plurality ofriser sections 108 connected in end to end relationship by suitable mechanical means asend connections 110 which may be threaded connections, flanged end connections or clamp hub connections as is well known to those of ordinary skill in the art. Some ofriser sections 108 have buoyancy tank orhousings 112 clamped thereon or they may be integrally formed therewith without departing from the scope of the invention. Buoyancy tank orhousings 112 air filled with compressed air to provide buoyancy to subseadrilling riser system 100 thereby lessening or obviating the need for a riser tensioner system.Upper riser connector 114 is provided near the upper end ofriser system 100 to allowdrilling rig 102 to disconnect fromriser system 100 in the event of a drive off or inclement weather that necessitates the suspension of drilling operations.Tether line 116, of suitable material as chain, wire or polyester rope, extends from buoyancy tank orhousings 112 to BOP stack 104 below the lower marine riser package where it is anchored for purposes that will be explained hereinafter. - As best seen in FIGS. 2 and 3, the first embodiment of the present invention includes buoyancy tank or
housing 210 attached toriser section 108. Buoyancy tank orhousing 210 includesfrangible section 212 to whichactuation ring 214 is attached.Tether line 116 is connected toactuation ring 214 and extends downwardly to BOP stack 104 as previously noted.Frangible section 212 includes circumferentially shapedchannel 216 in buoyancy tank orhousing 210 that is sealed by annularly shapedring 218. - Annularly shaped
ring 218 is sealed by frangible welded joint 220. Annularly shapedring 218 extends circumferentially around buoyancy tank orhousing 210 and is sealed completely around its periphery by frangible welded joint 220. Frangible welded joint 220 is sized to break when a suitable predetermined force is applied bytether line 116. Restrainingline 222 extends between buoyancy tank orhousing 210 andriser section 108 and connects to restraininghoops 224 that are welded tobuoyancy tank 210 andriser section 108. In the event of a catastrophic riser failure, i.e., where the riser below the buoyancy tanks or housings has parted, the positivelybuoyant riser sections 108 with attached buoyancy tank orhousings 210 will ascend to the surface with increasing velocity unless the compressed air in buoyancy tank orhousings 210 is vented immediately. As positivelybuoyant riser sections 108 with attached buoyancy tank orhousings 210 start to ascend toward the surface,tether line 116 is drawn taut and begins pulling onactuation ring 214. As best seen in FIG. 3, continued ascent ofriser sections 108 with attached buoyancy tank orhousings 210 causes frangible welded joint 220 to break and peel annularly shapedring 218 from buoyancy tank orhousings 210. This detachment of annularly shapedring 218 leaves circumferentially shapedchannel 216 open to sea water and thereby venting the compressed air from buoyancy tank orhousings 210 andrendering riser sections 108 negatively buoyant. Restrainingline 222 ensures that buoyancy tank orhousing 210 does not completely separate fromriser section 108 and thereby aids in salvage operations. - A second embodiment of the present invention is shown in FIGS. 4 and 5. Those items that are the same as in the first embodiment retain the same numeric designation. As in the first embodiment,
riser section 108 has buoyancy tank orhousing 310 attached thereto. Buoyancy tank orhousing 310 hastoggle clamp assembly 312 positioned at its upper end to whichactuation arm 314 is attached.Tether line 116 is connected toactuation arm 314 and extends downwardly to BOP stack 104 as previously noted.Toggle clamp assembly 312 holds toggle retainer clamps 322 in engagement retaining annularly shapedflange 316 that seals inside the top of buoyancy tank orhousing 310 with anannular seal ring 320. Annularly shapedflange 316 is attached and sealed againstriser section 108 bywelds 318. - Rapidly removable section such as annularly shaped
flange 316 is held by in sealing engagement with buoyancy tank orhousing 310 by toggle retainer clamps 322. Toggle retainer clamps 322 include afrangible retainer pin 324.Frangible retainer pin 324 is sized to break when a suitable predetermined force is applied bytether line 116. Restrainingline 326 extends between buoyancy tank orhousing 310 andriser section 108 and connects to restraininghoops 328 that are welded tobuoyancy tank 310 andriser section 108. As in the previous embodiments when a catastrophic riser failure occurs the ascent of positivelybuoyant riser sections 108 with attached buoyancy tank orhousings 310 causestether line 116 to be drawn taut and begins pulling onactuation arm 314. As best seen in FIG. 5, continued ascent ofriser sections 108 with attached buoyancy tank orhousings 310 causesfrangible retainer pin 324 to break and toggle retainer clamps 322 to release annularly shapedflange 316 from buoyancy tank orhousings 310. This detachment of annularly shapedflange 316 allows buoyancy tank orhousing 310 to vent the compressed air therein and renderriser sections 108 negatively buoyant. Restrainingline 326 ensures that buoyancy tank orhousing 310 does not completely separate fromriser section 108 and thereby aids in salvage operations. - A third embodiment of the present invention is shown in FIGS. 6 and 7. Those items that are the same as in the first embodiment retain the same numeric designation. As in the first embodiment,
riser section 108 has buoyancy tank orhousing 410 attached thereto. Buoyancy tank orhousing 410 hasretainer pin assembly 412 positioned at its upper end to whichactuation arm 414 is attached.Tether line 116 is connected toactuation arm 414 and extends downwardly to BOP stack 104 as previously noted.Retainer pin assembly 412 holdsretainer arm 416 in engagement retaining annularly shapedflange 418 that seals inside the top of buoyancy tank orhousing 410 with anannular seal ring 420. Rapidly removable section such as annularly shapedflange 418 is attached and sealed againstriser section 108 bywelds 422. - Annularly shaped
flange 418 is held by in sealing engagement with buoyancy tank orhousing 410 byretainer arm 416.Retainer arm 416 is held in position byretainer pin assembly 412 that includesremovable retainer pin 424.Removable retainer pin 424 is released when a suitable predetermined force is applied bytether line 116 toactuation arm 414 and pivotingretainer pin assembly 412 outwardly. Restrainingline 426 extends between buoyancy tank orhousing 410 andriser section 108 and connects to restraininghoops 428 that are welded tobuoyancy tank 410 andriser section 108. As in the previous embodiments when a catastrophic riser failure occurs the ascent of positivelybuoyant riser sections 108 with attached buoyancy tank orhousings 410 causestether line 116 to be drawn taut and begins pulling onactuation arm 414. As best seen in FIG. 7, continued ascent ofriser sections 108 with attached buoyancy tank orhousings 410 causesretainer pin assembly 412 to pivot outward and withdrawretainer pin 424 fromretainer arm 416 to release annularly shapedflange 418 from buoyancy tank orhousings 410. This detachment of annularly shapedflange 418 allows buoyancy tank orhousing 410 to vent the compressed air therein and renderriser sections 108 negatively buoyant. Restrainingline 426 ensures that buoyancy tank orhousing 410 does not completely separate fromriser section 108 and thereby aids in salvage operations. - A fourth embodiment of the present invention is shown in FIGS. 8 and 9. Those items that are the same as in the first embodiment retain the same numeric designation. As in the first embodiment,
riser section 108 has buoyancy tank orhousing 510 attached thereto. Buoyancy tank orhousing 510 hasexplosive bolt assembly 512 positioned at its upper end. A sensing means such astransceiver box 514 is attached to buoyancy tank or housing adjacentexplosive bolt assembly 512.Control lead 516 connectstransceiver box 514 to a remote releasing means such asexplosive bolt assembly 512.Explosive bolt assembly 512 retains annularly shapedflange 518 that seals inside the top of buoyancy tank orhousing 510 with anannular seal ring 520. Annularly shapedflange 518 is attached and sealed againstriser section 108 bywelds 522. - Rapidly removable section such as annularly shaped
flange 518 is held in sealing engagement with buoyancy tank orhousing 510 byexplosive bolt assembly 512.Explosive bolt assembly 512 is activated when upon detection of a parting of the riser a signal is sent to a sensing means such astransceiver box 514. Such signal could be mechanical, electrical, acoustic or hydraulic without departing from the scope of the present invention. Restrainingline 524 extends between buoyancy tank orhousing 510 andriser section 108 and connects to restraininghoops 526 that are welded tobuoyancy tank 510 andriser section 108. When a catastrophic riser failure occurs a signal is transmitted totransceiver box 514 that in turns firesexplosive bolt assembly 512 throughcontrol lead 516. As best seen in FIG. 9, the release ofexplosive bolt assembly 512 allows annularly shapedflange 518 to be released from buoyancy tank orhousings 510. This detachment of annularly shapedflange 518 allows buoyancy tank orhousing 510 to vent the compressed air therein and renderriser sections 108 negatively buoyant. Restrainingline 524 ensures that buoyancy tank orhousing 510 does not completely separate fromriser section 108 and thereby aids in salvage operations. - My improved apparatus to provide for rapid venting of the compressed air and deballasting of a buoyant air tank in a positively buoyant riser system in the event of a riser section parting and the methods of its application will be readily understood from the foregoing description. Furthermore, while the invention has been shown and described with respect to certain preferred embodiments, it is obvious that equivalent alterations and modifications will occur to others skilled in the art upon the reading and understanding of the specification. The present invention includes all such equivalent alterations and modifications, and is limited only by the scope of the appended claims.
Claims (4)
1. An emergency dump apparatus for buoyancy tanks or housings on buoyant riser systems in a subsea environment, comprising:
a buoyancy housing positioned about a riser section, said buoyancy housing including a frangible section;
a sensing means;
a remote releasing means positioned on said frangible section of said buoyancy housing and controlled by said sensing means, said sensing means activating said remote releasing means upon a parting of said riser to detach said frangible section from said buoyancy housing and flood said buoyancy housing.
2. An emergency dump apparatus for buoyancy tank or housings used on buoyant riser systems in a subsea environment according to wherein:
claim 1
said frangible section of said buoyancy housing includes an annular flange sealing the annulus between said riser section and said buoyancy housing to maintain pressure within said buoyancy housing prior to detachment of said frangible section.
3. An emergency dump apparatus for buoyancy tank or housings used on buoyant riser systems in a subsea environment according to wherein:
claim 2
said sensing means is responsive to a parting of the riser.
4. An emergency dump apparatus for buoyancy tank or housings used on buoyant riser systems in a subsea environment according to wherein:
claim 3
said remote releasing means is an explosive bolt assembly.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US09/915,011 US6394702B2 (en) | 1999-06-24 | 2001-07-25 | Emergency dump apparatus for buoyancy air tanks on buoyant riser systems |
Applications Claiming Priority (3)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US09/339,630 US6193441B1 (en) | 1999-06-24 | 1999-06-24 | Emergency dump apparatus for buoyancy air tanks on buoyant riser systems |
US09/753,348 US6296421B2 (en) | 1999-06-24 | 2001-01-02 | Emergency dump apparatus for buoyancy air tanks on buoyant riser systems |
US09/915,011 US6394702B2 (en) | 1999-06-24 | 2001-07-25 | Emergency dump apparatus for buoyancy air tanks on buoyant riser systems |
Related Parent Applications (1)
Application Number | Title | Priority Date | Filing Date |
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US09/753,348 Division US6296421B2 (en) | 1999-06-24 | 2001-01-02 | Emergency dump apparatus for buoyancy air tanks on buoyant riser systems |
Publications (2)
Publication Number | Publication Date |
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US20010041098A1 true US20010041098A1 (en) | 2001-11-15 |
US6394702B2 US6394702B2 (en) | 2002-05-28 |
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Application Number | Title | Priority Date | Filing Date |
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US09/339,630 Expired - Lifetime US6193441B1 (en) | 1999-06-24 | 1999-06-24 | Emergency dump apparatus for buoyancy air tanks on buoyant riser systems |
US09/753,348 Expired - Lifetime US6296421B2 (en) | 1999-06-24 | 2001-01-02 | Emergency dump apparatus for buoyancy air tanks on buoyant riser systems |
US09/915,011 Expired - Lifetime US6394702B2 (en) | 1999-06-24 | 2001-07-25 | Emergency dump apparatus for buoyancy air tanks on buoyant riser systems |
Family Applications Before (2)
Application Number | Title | Priority Date | Filing Date |
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US09/339,630 Expired - Lifetime US6193441B1 (en) | 1999-06-24 | 1999-06-24 | Emergency dump apparatus for buoyancy air tanks on buoyant riser systems |
US09/753,348 Expired - Lifetime US6296421B2 (en) | 1999-06-24 | 2001-01-02 | Emergency dump apparatus for buoyancy air tanks on buoyant riser systems |
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US (3) | US6193441B1 (en) |
BR (1) | BR0002848B1 (en) |
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US20070187109A1 (en) * | 2006-02-10 | 2007-08-16 | Millheim Keith K | System for and method of restraining a subsurface exploration and production system |
Families Citing this family (19)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
FR2807814B1 (en) * | 2000-04-17 | 2002-07-12 | Techlam | DEVICE FOR CONNECTING A SUBMERSIBLE FLUID TRANSPORT LINE |
US6435775B1 (en) * | 2000-05-22 | 2002-08-20 | Edo Corporation, Fiber Science Division | Buoyancy system with buoyancy module seal |
US6632112B2 (en) | 2000-11-30 | 2003-10-14 | Edo Corporation, Fiber Science Division | Buoyancy module with external frame |
US6595293B2 (en) | 2001-05-23 | 2003-07-22 | Cooper Cameron Corporation | Apparatus and method for connecting riser between a floating vessel and a subsea structure |
US6805201B2 (en) * | 2002-01-31 | 2004-10-19 | Edo Corporation, Fiber Science Division | Internal beam buoyancy system for offshore platforms |
US7096957B2 (en) * | 2002-01-31 | 2006-08-29 | Technip Offshore, Inc. | Internal beam buoyancy system for offshore platforms |
CA2457269A1 (en) * | 2003-02-11 | 2004-08-11 | Tough Traveler, Ltd. | An apparatus having a bottom opening pocket |
FR2858648B1 (en) * | 2003-08-08 | 2006-11-10 | Saipem Sa | FOND-SURFACE BONDING DEVICE COMPRISING A SEALED FLEXIBLE JOINT BETWEEN A RISER AND A FLOAT |
US7328747B2 (en) * | 2004-05-03 | 2008-02-12 | Edo Corporation, Fiber Science Division | Integrated buoyancy joint |
US8696247B2 (en) * | 2005-08-30 | 2014-04-15 | Kellogg Brown & Root Llc | Systems and methods for controlling risers |
US20090044950A1 (en) * | 2007-08-13 | 2009-02-19 | Boudreau Paul R | Buoyancy tensioning systems for offshore marine risers and methods of use |
US20110284237A1 (en) * | 2010-05-20 | 2011-11-24 | Benton Ferderick Baugh | Drilling riser release method |
US8708038B2 (en) * | 2011-06-30 | 2014-04-29 | Donnie C. Tucker | Pipe grapple |
US9879396B2 (en) | 2013-06-24 | 2018-01-30 | Trendsetter Vulcan Offshore, Inc. | Systems and methods for tethering subsea structure mounted on a wellhead |
WO2014210026A2 (en) * | 2013-06-24 | 2014-12-31 | Bp Corporation North America, Inc. | Systems and methods for tethering subsea blowout preventers to enhance the strength and fatigue resistance of subsea wellheads and primary conductors |
US11187052B2 (en) * | 2016-12-08 | 2021-11-30 | Kinetic Pressure Control Ltd. | Explosive disconnect |
CN110036178A (en) * | 2016-12-08 | 2019-07-19 | 动压控制有限责任公司 | Explosivity disconnects |
CN106968610B (en) * | 2017-04-26 | 2019-07-19 | 中国石油大学(华东) | A kind of Offshore Drilling Riser that itself can be monitored is single |
EP3981946A1 (en) * | 2020-10-06 | 2022-04-13 | Kinetic Pressure Control, Ltd. | Explosive disconnect |
Family Cites Families (12)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3855656A (en) | 1973-03-30 | 1974-12-24 | Amoco Prod Co | Underwater buoy for a riser pipe |
GB1519203A (en) | 1974-10-02 | 1978-07-26 | Chevron Res | Marine risers in offshore drilling |
US4176986A (en) | 1977-11-03 | 1979-12-04 | Exxon Production Research Company | Subsea riser and flotation means therefor |
CA1136545A (en) | 1979-09-28 | 1982-11-30 | Neville E. Hale | Buoyancy system for large scale underwater risers |
US4511287A (en) | 1980-05-02 | 1985-04-16 | Global Marine, Inc. | Submerged buoyant offshore drilling and production tower |
US4448266A (en) * | 1980-11-14 | 1984-05-15 | Potts Harold L | Deep water riser system for offshore drilling |
US4432420A (en) | 1981-08-06 | 1984-02-21 | Exxon Production Research Co. | Riser tensioner safety system |
US4646840A (en) | 1985-05-02 | 1987-03-03 | Cameron Iron Works, Inc. | Flotation riser |
US5046896A (en) | 1990-05-30 | 1991-09-10 | Conoco Inc. | Inflatable buoyant near surface riser disconnect system |
US5657823A (en) | 1995-11-13 | 1997-08-19 | Kogure; Eiji | Near surface disconnect riser |
US5706897A (en) * | 1995-11-29 | 1998-01-13 | Deep Oil Technology, Incorporated | Drilling, production, test, and oil storage caisson |
US5758990A (en) * | 1997-02-21 | 1998-06-02 | Deep Oil Technology, Incorporated | Riser tensioning device |
-
1999
- 1999-06-24 US US09/339,630 patent/US6193441B1/en not_active Expired - Lifetime
-
2000
- 2000-06-21 BR BRPI0002848-7A patent/BR0002848B1/en not_active IP Right Cessation
-
2001
- 2001-01-02 US US09/753,348 patent/US6296421B2/en not_active Expired - Lifetime
- 2001-07-25 US US09/915,011 patent/US6394702B2/en not_active Expired - Lifetime
Cited By (6)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US20070187109A1 (en) * | 2006-02-10 | 2007-08-16 | Millheim Keith K | System for and method of restraining a subsurface exploration and production system |
WO2007092051A1 (en) * | 2006-02-10 | 2007-08-16 | Anadarko Petroleum Corporation | System for and method of restraining a subsurface exploration and production system |
EA013092B1 (en) * | 2006-02-10 | 2010-02-26 | Анадарко Петролеум Корпорейшен | System and method of restraining subsurface exploration and production system |
AU2006337668B2 (en) * | 2006-02-10 | 2011-01-27 | Anadarko Petroleum Corporation | System for and method of restraining a subsurface exploration and production system |
AP2423A (en) * | 2006-02-10 | 2012-06-13 | Anadarko Petroleum Corp | System for and method of restraining a subsurface exploration and production system. |
NO338609B1 (en) * | 2006-02-10 | 2016-09-12 | Anadarko Petroleum Corp | System and method for retaining an exploration and production system below the surface |
Also Published As
Publication number | Publication date |
---|---|
US6296421B2 (en) | 2001-10-02 |
US6394702B2 (en) | 2002-05-28 |
BR0002848A (en) | 2001-01-30 |
US20010001633A1 (en) | 2001-05-24 |
US6193441B1 (en) | 2001-02-27 |
BR0002848B1 (en) | 2009-01-13 |
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