GB2285650A - Riser tensioner system for use on offshore platforms using nested elastomeric pads or helical metal compression springs - Google Patents
Riser tensioner system for use on offshore platforms using nested elastomeric pads or helical metal compression springs Download PDFInfo
- Publication number
- GB2285650A GB2285650A GB9505462A GB9505462A GB2285650A GB 2285650 A GB2285650 A GB 2285650A GB 9505462 A GB9505462 A GB 9505462A GB 9505462 A GB9505462 A GB 9505462A GB 2285650 A GB2285650 A GB 2285650A
- Authority
- GB
- United Kingdom
- Prior art keywords
- riser
- spring
- housing
- rod
- end portion
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
- 230000006835 compression Effects 0.000 title claims description 40
- 238000007906 compression Methods 0.000 title claims description 40
- 239000002184 metal Substances 0.000 title claims description 7
- 238000005553 drilling Methods 0.000 claims abstract description 18
- 238000007667 floating Methods 0.000 claims description 14
- 230000008878 coupling Effects 0.000 claims description 4
- 238000010168 coupling process Methods 0.000 claims description 4
- 238000005859 coupling reaction Methods 0.000 claims description 4
- 239000003381 stabilizer Substances 0.000 claims description 3
- 239000006096 absorbing agent Substances 0.000 description 38
- 230000035939 shock Effects 0.000 description 38
- 230000004044 response Effects 0.000 description 9
- 239000012530 fluid Substances 0.000 description 4
- 230000003534 oscillatory effect Effects 0.000 description 4
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 4
- 229920001971 elastomer Polymers 0.000 description 3
- 230000008901 benefit Effects 0.000 description 2
- 239000000806 elastomer Substances 0.000 description 2
- 239000013536 elastomeric material Substances 0.000 description 2
- 230000001965 increasing effect Effects 0.000 description 2
- 239000000463 material Substances 0.000 description 2
- 230000007246 mechanism Effects 0.000 description 2
- 238000000034 method Methods 0.000 description 2
- 230000009471 action Effects 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- 230000008859 change Effects 0.000 description 1
- 238000005520 cutting process Methods 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 230000002708 enhancing effect Effects 0.000 description 1
- 239000006260 foam Substances 0.000 description 1
- 238000005755 formation reaction Methods 0.000 description 1
- 238000012423 maintenance Methods 0.000 description 1
- 238000010008 shearing Methods 0.000 description 1
- 239000011800 void material Substances 0.000 description 1
- 239000003643 water by type Substances 0.000 description 1
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
- E21B19/00—Handling rods, casings, tubes or the like outside the borehole, e.g. in the derrick; Apparatus for feeding the rods or cables
- E21B19/002—Handling rods, casings, tubes or the like outside the borehole, e.g. in the derrick; Apparatus for feeding the rods or cables specially adapted for underwater drilling
- E21B19/004—Handling rods, casings, tubes or the like outside the borehole, e.g. in the derrick; Apparatus for feeding the rods or cables specially adapted for underwater drilling supporting a riser from a drilling or production platform
- E21B19/006—Handling rods, casings, tubes or the like outside the borehole, e.g. in the derrick; Apparatus for feeding the rods or cables specially adapted for underwater drilling supporting a riser from a drilling or production platform including heave compensators
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16F—SPRINGS; SHOCK-ABSORBERS; MEANS FOR DAMPING VIBRATION
- F16F2236/00—Mode of stressing of basic spring or damper elements or devices incorporating such elements
- F16F2236/04—Compression
- F16F2236/045—Compression the spring material being generally enclosed
Landscapes
- Engineering & Computer Science (AREA)
- Life Sciences & Earth Sciences (AREA)
- Geology (AREA)
- Mining & Mineral Resources (AREA)
- Mechanical Engineering (AREA)
- Physics & Mathematics (AREA)
- Environmental & Geological Engineering (AREA)
- Fluid Mechanics (AREA)
- General Life Sciences & Earth Sciences (AREA)
- Geochemistry & Mineralogy (AREA)
- Earth Drilling (AREA)
Abstract
A riser tensioner system (10) is provided for applying a generally upward force to a riser whilst allowing limited vertical movement the riser and an oil drilling platform. The riser has a plunger assembly adapted for telescopic movement. The plunger assembly has a rod (28) having a first end portion and a plate (30) coupled to the second end portion of the rod (28). At least one inner spring (50) and one outer spring (52) are compressed by the plunger assembly. A strut (18) has first and second end portions and an intermediate portion, the intermediate portion being rotatably coupled to the plunger assembly, the strut first end portion being rotatably coupled to the offshore drilling platform, and the strut second end portion being rotatably coupled to the riser. <IMAGE>
Description
RISER PENSIONER SYSTEM FOR USE ON OFFSHORE PLSIFORMS USING ELASPOMERIC PADS OR HELICAL METAL
COMPRESSION SPRINGS
This invention relates generally to riser tensioner systems for use on offshore platforms and, more particularly, to a riser tensioner system that utilizes a compression spring to absorb oscillatory, vertical movement of the platform while supporting the riser.
Increased oil consumption has led to exploration and drilling in difficult geographic locations that were previously considered to be economically unfeasible. As is to be expected, drilling under these difficult conditions leads to problems that are not present under more ideal conditions. For example, an increasing number of exploratory wells are being drilled in deep water, offshore locations in an attempt to locate more oil and gas reservoirs. These exploratory wells are generally drilled from floating platforms, leading to a set of problems peculiar to that environment.
As in any drilling operation, offshore drilling requires that drilling fluid must be circulated through the drill bit to cool the bit and to carry away the cuttings. This drilling fluid is normally delivered to the drill bit through the drill string and returned to the floating vessel through an annulus formed between the drill string and a large diameter pipe, commonly known as a riser. The riser typically extends between a subsea wellhead assembly and the floating vessel and is sealed against water intrusion.
The lower end of this riser is connected to the wellhead assembly adjacent the ocean floor, and the upper end usually extends through a centrally located opening in the hull of the floating vessel. The drill string extends longitudinally through the riser and into earth formations lying below the body of water, and drilling fluid circulates downwardly through the drill string, out through the drill bit, and then upwardly through the annular space between the drill string and the riser, returning to the vessel.
As these drilling operations progress into deeper waters, the length of the riser and, consequently, its unsupported weight also increases. Riser structural failure may result if compressive stresses in the elements of the riser exceed the metallurgical limitations of the riser material. Riser tensioner systems are typically used to avoid of this type of riser failure.
Riser tensioner systems are installed onboard the platform, and apply an upward force to the upper end of the riser, usually by means of cable, sheave, and pneumatic cylinder mechanisms connected between the vessel and the upper end of the riser.
In addition, buoyancy or ballasting elements may also be attached to the submerged portion of the riser. These usually are comprised of synthetic foam elements or individual ballast or buoyancy tanks formed on the outer surface of the riser sections. The ballast or buoyancy tanks are capable of being selectively inflated with air or ballasted with water by using the floating vessel's air compression equipment. These buoyancy devices create upwardly directed forces in the riser, and, thereby, compensate for the compressive stresses created by the riser's weight.
Both types of these mechanisms suffer from inherent disadvantages. Hydraulic and pneumatic tensioning systems are large, heavy, and require extensive support equipment, such as, air compressors, hydraulic fluid, reservoirs, piping, valves, pumps, accumulators, electrical power, and control systems. The complexity of these systems necessitate extensive and frequent maintenance with their attendant high cost.
The present invention is directed to overcoming or minimizing one or more of the problems set forth above.
According to the present invention, there is provided a riser tensioner system for mounting between a floating platform and a riser, and for applying a generally upward force to the riser whilst allowing limited vertical movement therebetween, the system comprising:
a housing having a central opening extending therein, the housing being adapted for coupling to the floating platform;
a plunger assembly adapted for telescopic movement within the central opening of the housing, the plunger assembly comprising: a rod having first and second end portions, the rod first end portion being adapted to couple to the riser; and, a plate coupled to the second end portion of the rod and positioned within the housing central opening;
at least one inner spring located within the housing and having a longitudinal axis substantially aligned with the axis of the rod;
at least one outer spring located within the housing and having a longitudinal axis substantially aligned with the longitudinal axis of the rod, the outer spring having a diameter greater than the diameter of the inner spring, and being adapted for receiving the inner spring longitudinally disposed therein;;
a spring separator positioned between and contacting the inner and outer springs, the inner and outer springs being compressed by the plunger assembly urging one of the inner and outer springs against the spring separator, and the spring separator urging the other of the inner and outer springs against the housing; and,
a strut having first and second end portions and an intermediate portion, the intermediate portion being rotatably coupled to the plunger assembly, the strut first end portion being rotatably coupled to the offshore drilling platform, and the strut second end portion being rotatably coupled to the riser.
Other objects and advantages of the invention will become apparent upon reading the following detailed description and upon reference to the drawings, in which:
Fig. 1 illustrates a partially cut-away, perspective view of a first embodiment of a compression mode riser tensioner system with nested elastomeric pads;
Fig. 1A illustrates a cross sectional side view of one embodiment of a pair of elastomeric pads used in the riser tensioner system of Fig. 1;
Fig. 1B illustrates a cross sectional side view of another embodiment of a pair of elastomeric pads used in the riser tensioner system of Fig. 1;
Fig. 2 shows a cross sectional side view of another embodiment of a compression mode riser tensioner system that uses a nested arrangement of elastomeric pads;;
Fig. 3 shows a cross sectional side view of an embodiment of a tension mode riser tensioner system that uses a nested arrangement of elastomeric pads;
Fig. 4 illustrates a cross sectional side view of another embodiment of a compression mode riser tensioner system using conical elastomeric pads in a nested configuration;
Fig. 5 illustrates a partially cut-away, perspective view of a riser tensioner system using nested stacks of compression type helical springs;
Fig. 6 illustrates a cross sectional side view of the riser tensioner system of Fig. 5 arranged to operate in the tension mode;
Fig. 7 illustrates a cross sectional side view of the riser tensioner system of Fig. 5 arranged to operate in the compression mode;
Fig. 8 illustrates a perspective view of another embodiment of a riser tensioner system that employs three parallel shock absorbers attached to the strut; and,
Fig. 9 illustrates a perspective view of another embodiment of a riser tensioner system that uses three parallel shock absorbers and a series of lever arms to enhance the force applied to the riser.
Referring now to the drawings and, in particular, to
Fig. 1, a perspective view of a riser tensioner system 10 is illustrated. The riser tensioner system 10 is connected to a riser 12 that extends from a subsea wellhead (not shown) to a floating platform (not shown).
As is to be expected, the floating platform oscillates relative to the riser 12 in accordance with wave action.
The riser tensioner system 10 compensates for this oscillatory movement of the floating platform while supporting the riser 12 and preventing it from collapsing under its own weight.
The riser tensioner system 10 is mounted to the floating platform (not shown) via a pair of spaced-apart, pin-type connections 14, 16 located within a first end portion of a strut 18 and shock absorber 20, respectively.
The strut 18 also has a second end portion pivotally coupled to the riser 12 via a sleeve 22 and pin-type connection 24. The shock absorber 20 is positioned below the strut 18 and has a second end portion connected to an intermediate portion of the strut 18 to support the strut 18 and riser 12. In this manner, the riser tensioner system 10 supports the riser 12 and prevents it from collapsing under its own weight, while still allowing limited vertical movement of the riser 12 relative to the floating platform.
The shock absorber 20 is formed from a generally cylindrical housing 26 having a central passage 27 extending longitudinally therethrough and opening adjacent the shock absorber second end portion. A rod 28 forms the shock absorber second end portion and extends longitudinally into the housing central passage 27, but is capable of limited telescopic movement therewith.
A plate 30 is connected to and movable with the rod 28, but is captured within the central passage 27. A plurality of nested elastomeric pads 32 are positioned in contact with one another and are longitudinally disposed in the central passage 27 between the plate 30 and the first end portion of the shock absorber 20. Thus, downward relative movement of the riser 12 urges the strut 18 to pivot about the pin-type connection 14 and force the rod 28 and plate 30 downward, toward the first end portion of the shock absorber 20, compressing the elastomeric pads 32. The combined spring rate of the elastomeric pads 32 effectively resists downward relative movement of the riser 12.
A riser tensioner system 10 of the type illustrated in Fig. 1 is herein referred to as a compression mode riser tensioner system because the shock absorber 20, as a whole, is compressed by downward movement of the riser 12.
As is more fully described below, a second embodiment of the riser tensioner system 10 is illustrated in which the shock absorber 20, as a whole, is placed in tension by downward movement of the riser 12, and, therefore, is referred to as a tension mode riser tensioner system.
The riser tensioner system 10 of the present invention places the elastomeric pads 32 in compression instead of shear. Placing the elastomeric pads 32 in compression offers the advantage of a longer fatigue life and a more acceptable failure mode.
Deflections of the elastomeric pads 32 in compression allows the riser 12 to stroke, or change the amount of compression, while maintaining tension on the riser 12.
The spring rate of the shock absorber 20 is determined by the number of elastomeric pads 32 in the stack. The spring rate may also be manipulated by varying the modulus of the elastomer as well as the shape of the elastomeric material.
A further means of achieving a desired response curve is to use varying moduli of rubber throughout the stack of elastomeric pads. Varying the moduli through the stack of the elastomeric pads will activate more springs as the load increases and will allow softening of the curve where needed. Changing the modulus is designed to enhance the input-output response ratio so as to flatten the load vs.
deflection curve of the shock absorber 20. The ideal curve is a constant load over a large deflection range so as to minimize the oscillatory stresses in the riser tensioner apparatus.
The nested elastomeric pads 32 have inner elastomeric pads 50 and outer elastomeric pads 52. The nested arrangement of elastomeric pads 32 is another way of varying the response curve and allowing greater stroke and response range of the shock absorber 20.
Figs. 1A and B illustrate first and second embodiments of the outer elastomeric pads 52. In the first embodiment shown in Fig. 1A, the outer elastomeric pad 52 includes a metallic disk 54 with a pair of elastomeric disks 56, 58 bonded on opposite sides thereof. The elastomeric disks 56, 58 and the metallic disk 54 have a relatively large central opening 60 to accept the inner elastomeric disks 50 therein. Further, to vary the response characteristics of the shock absorber 20, the elastomeric disks 56, 58 are formed with an annular void 62 extending therethrough.
Guide pins 66 and corresponding openings 68 are formed on the elastomeric disks 56, 58 to prevent rotation of the elastomeric pads 52 relative to one another. The guide pins 66 can take the form of elastomer material bonded to or formed with the elastomeric disks 56, 58, or, alternatively, may be formed by an extension of the metallic disk 54.
The second embodiment illustrated in Fig. 1B is substantially similar to the first embodiment, differing slightly in the shape of the elastomeric disks 56, 58 and having no voids formed therein. These differences in the configuration of the elastomeric disks 56, 58 are used to vary the response characteristics of the shock absorber 20.
Fig. 2 shows a cross sectional side view of the nested shock absorber 20 shown in Fig. 1. A nested pad plunger 70 is constructed from a rod 72 and plate 74 which telescopes into and out of a nested pad housing 76. The nested pad plunger 70 applies pressure directly to the inner elastomeric pads 50. The inner elastomeric pads 50 transfer force from the nested pad plunger 70 to an inner and outer elastomeric pad separator 78. The inner and outer elastomeric pad separator 78 transfers force to the outer elastomeric pads 52 which rest against the nested pad housing 76.
Fig. 3 shows a cross sectional side view of a second embodiment of a nested shock absorber 20 arranged as a tension mode shock absorber 20. The shock absorber 20 of
Fig. 3, although used in tension mode, advantageously maintains the inner elastomeric pads 50 and outer elastomeric pads 52 in compression. The shock absorber 20 is formed by inverting the nested pad plunger 70 in the nested pad housing 76. By pulling on the rod 72 of the inverted nested pad plunger 70, the same forces are applied to the remaining components of the shock absorber 20, as in
Fig. 2.
Fig. 4 shows another embodiment of a shock absorber 20 which uses conical elastomeric pads 88 in a nested configuration. The shock absorber 20 consists of the conical nested pad plunger 70, which telescopes into and out of conical nested pad housing 76, inner conical pads 90, outer conical pads 92, and an inner and outer conical pad separator 94. The conical elastomeric pads 88 deform in both the shear and compression directions, however, the compression spring rate dominates at most angles. The conical configuration offers the reliability of compression with a softer spring rate due to partial shearing deflection. The conical configuration also has a greater column alignment stability than a flat elastomeric pad.
Fig. 5 shows a tension mode shock absorber 20 using nested stacks of compression type helical springs 100 arranged in a series array as a substitute for the elastomeric pads of the previous embodiments. Operation of this helical spring embodiment is substantially similar to the previous elastomeric spring embodiments, but advantageously applies the highly developed and well understood field of metal spring technology.
Fig. 6 is a cross sectional view of Fig. 5, showing the tension mode nested spring shock absorber 20, with the springs 100 placed in compression, much like the elastomeric shock absorber of Fig. 3. Operating the spring in compression offers enhanced fatigue life and fail-safe operation just as with an elastomeric material shown in Fig. 3.
The nested spring shock absorber 20 of Figs. 5 and 6 consists of the nested compression spring plunger 70 telescoping into and out of the nested compression spring housing 76. The nested compression spring plunger 70 compresses inner compression springs 102 which transfer force to the inner and outer nested compression spring separator 104. The inner and outer nested compression separator 104 transfers force to the outer compression springs 106, which are supported by the nested compression spring housing 76. Intermediate separator plates 108 separate the stacks of inner compression springs 102 and outer compression springs 106. The intermedlate stabilizer plates 108 reduce column instability.
Fig. 7 shows the nested spring shock absorber 20 of
Fig. 6 with the shock absorber 20 and nested metal springs 100 placed in compression similar to the elastomeric pad shock absorber of Fig. 2. The shock absorber 20 of Fig. 7 has the same components as Fig. 6, with the nested compression spring plunger 70 inverted in the nested compression spring housing 76.
Figs. 8 and 9 show that the response characteristics of a riser tensioner system 10 may also be manipulated via the use of mechanical lever systems and by adding multiple shock absorbers 20. By this means the response curve can be tailored as required. Such measures will allow enhancing the input-output response ratio and flattening of the load vs. deflection curve of the riser tensioner system 10. The ideal curve is a constant load over a large deflection range. This serves to minimize the oscillatory stresses in the riser system.
Reference is made to application no. 9118562.9, from which the present application is divided, and in which there is disclosed, in one aspect, a riser tensioner system adapted for use in an offshore drilling platform to support a riser whilst allowing limited vertical movement therebetween, the system comprising:
a strut having a first and second end portion and an intermediate portion, the first end portion being adapted to couple to the offshore drilling platform, and the second end portion being adapted to connect to the riser;
a first shock absorber having a rod and plate assembly telescoping into and out of a housing adapted to couple to the offshore drilling platform, the rod being coupled at a first end portion to the plate and at a second end portion to the intermediate portion of the strut; and
a spring positioned in the housing between the housing and the plate, whereby movement of the riser and strut in a first direction is resisted by the spring being compressed between the plate and housing.
In another aspect, there is disclosed a method for using a shock absorber and strut to support a riser on an offshore drilling platform whilst allowing limited vertical movement therebetween, the method comprising the steps of:
rotatably coupling a first end portion of the strut to the riser and a second end portion of the strut to the offshore drilling platform;
rotatably coupling the shock absorber at a first end portion to the strut and at a second end portion to the drilling platform; and,
positioning a spring within the shock absorber so that movement of the riser and strut in a first direction is resisted by compression of the spring within the shock absorber.
Claims (4)
1. A riser tensioner system for mounting between a floating platform and a riser, and for applying a generally upward force to the riser whilst allowing limited vertical movement therebetween, the system comprising:
a housing having a central opening extending therein, the housing being adapted for coupling to the floating platform;
a plunger assembly adapted for telescopic movement within the central opening of the housing, the plunger assembly comprising: a rod having first and second end portions, the rod first end portion being adapted to couple to the riser; and, a plate coupled to the second end portion of the rod and positioned within the housing central opening;
at least one inner spring located within the housing and having a longitudinal axis substantially aligned with the axis of the rod;
at least one outer spring located within the housing and having a longitudinal axis substantially aligned with the longitudinal axis of the rod, the outer spring having a diameter greater than the diameter of the inner spring, and being adapted for receiving the inner spring longitudinally disposed therein;;
a spring separator positioned between and contacting the inner and outer springs, the inner and outer springs being compressed by the plunger assembly urging one of the inner and outer springs against the spring separator, and the spring separator urging the other of the inner and outer springs against the housing; and,
a strut having first and second end portions and an intermediate portion, the intermediate portion being rotatably coupled to the plunger assembly, the strut first end portion being rotatably coupled to the offshore drilling platform, and the strut second end portion being rotatably coupled to the riser.
2. A riser tensioner system according to claim 1, wherein the inner and outer springs comprise:
a plurality of longitudinally disposed helical compression springs having a longitudinal axis generally aligned with the rod; and,
intermediate stabilizer plates located within the housing central opening in longitudinally spaced apart relationship, positioned between the helical compression springs.
3. A riser tensioner system according to claim 1, wherein the inner and outer springs each comprise:
at least one helical metal compression spring having a longitudinal axis generally aligned with the longitudinal axis of the plunger assembly.
4. A riser tensioner system according to claim 1, wherein the inner and outer springs each comprise:
at least two longitudinally displaced helical metal compression springs having longitudinal axes generally aligned with the longitudinal axis of the plunger assembly; and,
at least one intermediate stabilizer plate positioned between and separating the helical metal compression springs.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB9505462A GB2285650B (en) | 1990-12-13 | 1991-08-30 | Riser tensioner system for use on offshore platforms using elastomeric pads or helical metal compresion springs |
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US62843990A | 1990-12-13 | 1990-12-13 | |
| GB9118562A GB2250763B (en) | 1990-12-13 | 1991-08-30 | Riser tensioner system for use on offshore platforms using elastomeric pads or helical metal compression springs |
| GB9505462A GB2285650B (en) | 1990-12-13 | 1991-08-30 | Riser tensioner system for use on offshore platforms using elastomeric pads or helical metal compresion springs |
Publications (3)
| Publication Number | Publication Date |
|---|---|
| GB9505462D0 GB9505462D0 (en) | 1995-05-03 |
| GB2285650A true GB2285650A (en) | 1995-07-19 |
| GB2285650B GB2285650B (en) | 1995-09-20 |
Family
ID=26299458
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB9505462A Expired - Fee Related GB2285650B (en) | 1990-12-13 | 1991-08-30 | Riser tensioner system for use on offshore platforms using elastomeric pads or helical metal compresion springs |
Country Status (1)
| Country | Link |
|---|---|
| GB (1) | GB2285650B (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| FR3025787B1 (en) * | 2014-09-16 | 2019-06-07 | IFP Energies Nouvelles | SYSTEM FOR MONITORING THE MOVEMENT OF A LOAD |
Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB2251874A (en) * | 1991-01-15 | 1992-07-22 | Ltv Energy Prod Co | Variable spring rate riser tensioner system |
-
1991
- 1991-08-30 GB GB9505462A patent/GB2285650B/en not_active Expired - Fee Related
Patent Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB2251874A (en) * | 1991-01-15 | 1992-07-22 | Ltv Energy Prod Co | Variable spring rate riser tensioner system |
Also Published As
| Publication number | Publication date |
|---|---|
| GB2285650B (en) | 1995-09-20 |
| GB9505462D0 (en) | 1995-05-03 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| US5366324A (en) | Riser tensioner system for use on offshore platforms using elastomeric pads or helical metal compression springs | |
| US5433423A (en) | Elastomeric strut for an elastomeric riser tensioner | |
| US4808035A (en) | Pneumatic riser tensioner | |
| US5160219A (en) | Variable spring rate riser tensioner system | |
| EP0408685B1 (en) | A method and a device for movement-compensation in riser pipes | |
| EP0894939B1 (en) | Controlled pressure multi-cylinder riser tensioner and method | |
| US4367981A (en) | Fluid pressure-tensioned slip joint for drilling riser | |
| US4848967A (en) | Load-transfer system for mating an integrated deck with an offshore platform substructure | |
| US4449854A (en) | Motion compensator system | |
| JPS62155322A (en) | Elastic ball joint supporter | |
| US4662786A (en) | Dynamic load compensating system | |
| US20020084077A1 (en) | Gimbaled table riser support system | |
| GB1591483A (en) | Joint assembly | |
| US5101905A (en) | Riser tensioner system for use on offshore platforms | |
| EP0360364B1 (en) | Riser tensioner | |
| US3897045A (en) | Riser pipe and guide line tensioning apparatus | |
| US4721417A (en) | Compliant offshore structure stabilized by resilient pile assemblies | |
| US4471709A (en) | Pretensioned catenary free deep sea mooring system | |
| US3779040A (en) | Vibration dampeners | |
| CA1192752A (en) | Well support system | |
| GB2285650A (en) | Riser tensioner system for use on offshore platforms using nested elastomeric pads or helical metal compression springs | |
| CA1205740A (en) | Marine riser tensioner | |
| US20020142683A1 (en) | Nonstructural buoyancy can | |
| EP0054091A1 (en) | Compression shock absorber device | |
| AU2002238025B2 (en) | Nonstructural buoyancy can |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PCNP | Patent ceased through non-payment of renewal fee |
Effective date: 20020830 |