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
  • E21B33/00—Sealing or packing boreholes or wells
  • E21B33/10—Sealing or packing boreholes or wells in the borehole
  • E21B33/13—Methods or devices for cementing, for plugging holes, crevices or the like
  • E21B33/14—Methods or devices for cementing, for plugging holes, crevices or the like for cementing casings into boreholes
• • 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
  • E21B2200/00—Special features related to earth drilling for obtaining oil, gas or water
  • E21B2200/01—Sealings characterised by their shape
• • 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
  • E21B2200/00—Special features related to earth drilling for obtaining oil, gas or water
  • E21B2200/06—Sleeve valves

Definitions

• the present invention relates to a sealing device to be used in tough conditions, such as conditions with strongly varying pressure, conditions with strongly varying temperature and conditions with an chemically stressing environment.
• the sealing device according to the present invention shall fullfil the requirement of a reliable and maintenancefree function in the long run.
• the oil industry uses a great variety of sealing device in all stages of the processes which lead to the conduction of oil and gas from a subterranean reser- voir, up to the surface and on to the end user.
• the present invention particularly relates to sealing devices to be used underground, but the advantages of the sealing devices according to the present invention may also find their use in other context where there is a need for robust sealing devices.
• cementing valves When completing oil and gas wells so-called cementing valves are used in the cementing work.
• the cementing valves form parts of the production tubing and is arranged in such a way that they can be opened and closed as needed during the cementing work.
• Cementing valves are subjected to large and varying loadings, such as large pressure differentials, elevated temperatures and/or large temperature variations, strong physical loadings and also a very tough chemical environment.
• One kind of cementing valves comprises an inner sleeve which can be slid back and forth to close and open radial valve openings or -ports in a base tube, respectively, an open cementing valve form communication between the inside and outside of production tubing.
• the base tube is screwed in as a part of the pro- duction tubing, the cementing valve thereby form a tubing section of the production tubing.
• ring shaped sealing devices are arranged between the outside of the inner sleeve and the inside of the base tube. These ring shaped sealing devices are usually situated in encircling grooves which are milled out or in another way are arranged in the sleeve.
• sealing ring there is a limited range of materials which are suitable for use in sealings of this kind.
• One way to arrange the sealing ring in the sealing groove is to heat expand the sealing ring when it is threaded over the sleeve and into the sealing groove. When the sealing ring is cooled down, it will tighten into place in the sealing groove.
• This method does, however, limit the material choice with a view to strenghts and temperature resistance, chemical resistance and tolerance to pressure.
• Some of the chemicals the sealing can be exposed to down in the well comprise formic acid, hydrochloric acid, saline solutions, acid gases such as H 2 , etc. It is a known problem that elevated temperatures can make the sealings brittle.
• Futher gas may penetrate into the sealing material and form gas bobbles which cause the sealing to "blow up".
• sealings can be dissolved in mud. The combination of these factors, which sometimes also occure concurrently, make the choice of sealing material difficult.
• the sealing in addition must have certain mechanical qualities in order to enable installation, the choice is further limited.
• Teflon has a tendency to expand and get softer at elevated temperatures, but will again retract when the temperature falls.
• a material called Devlon V has inter alia been used. Devlon V is mechanically stronger than Teflon and will endure higher differential pressures than e.g. Teflon. Although Devlon V also ex- ,
• Devlon V has a melting point of 216 0 C. If the sealings shall be used in environments with even higher temperatures, there is a material called Peek which endure up to 333°C. If Teflon or Peek is used in environments with H 2 S, the sealings will swell and get brittle over time. There are other materials which can be used, but this may be at the expence of other qualities. Price is also a factor which of course is taken into consideration: Devlon V is considerably more expensive than Teflon and Peek is considerable more expensive than Devlon V, etc.
• the sealings must be flexible enought to be threaded over the cementing valve sleeve and down into a groove arranged for that purpose. If the requirements to mechanical strenghts of the sealing are particularly strict, the sealing of the preferred sealing material will be too hard to be threaded over the sleeve.
• Fig. 1 illustrate a conventional sealing system
• Fig. 2 and 3 illustrate longitudinal sections of a cementing valve provided with the sealing device according to the present invention
• FIG. 4 and 5 illustrate in closer detail the sealing device according the present invention.
• Fig. 1 illustrates a conventional sealing system in conjunction with a sleeve
• a sealing in the shape of an O-ring 21 is arranged in a groove 22 which encircles the sleeve 20.
• the groove 22 in the sleeve 20 is big enough to contain additional rings 23, 24 which purpose is to protect the O-ring 21 , but these additional rings 23, 24 does not contribute to support and retain the O- ring in place by radially outwardly directed forces.
• the rings 23, 24 are similar to the O-ring 21 preferably manufactured from Teflon, and must similar to the O-ring
• the present invention provides a sealing device 10 (see fig. 2 to 5) which comprises a sealing 1 , e.g. in the form of a sealing ring, which is held in place by support rings 2.
• the support rings 2 functions as shape-adapted keys which both contribute to clamping around the sealing 1 and which themselves are keyed or clamped into position by outer locking rings 3.
• the outer locking rings 3 are in turn shaped to fit into suitable locking grooves 6 in sleeve 7.
• Sleeve 7 comprises a threaded portion 8 and also possibly a recessed portion 9 which contribute to reducing the diameter 11 of the sleeve.
• the sealing device 10 is arranged in such a way that an applied differential pressure will cause the sealing 1 , the support rings 2 and the locking rings 3 to interlock and thereby protect against scouring. .
• the sealing device 10 gives much greater freedom in choice of materials for the sealing 1. Because the support rings 2 and the locking rings 3 are arranged to take up many of the mechanical loadings, and since the sealing 1 in itself can be put in place without the need to heat expand it in advance or forcibly threaded over the sleeve 1 and down in a locking groove, materials may be chosen for the sealing 1 which to a much larger extent have good sealing, thermal, chemical, pressure and abrasion properties.
• the material which the support rings 2 are manufactured from may also be adapted to the use and the material which the sealing 1 is made from, and may also be manu- factured from the same material as the sealing 1.
• the locking rings 3 will preferably be manufactured from the same material as sleeve 7, but may also be manufactured from another material, e.g. a material which has properties which can be said to be between the material which sleeve 7 is manufactured from and the material the support ring 2 are manufactured from with respect to hardness, tough-5 ness, expansibility, etc.
• the locking nut 5 is as a rule manufactured from the same or equivalent material as sleeve 7.
• the sealing device 10 is allowed to expand when pressure and temperature increase.
• the sealing device 10 is arranged in such a way that the sealing 1 gets better supporto the higher pressure the sealing device 10 is subjected to.
• the support rings 2 will press harder against the sealing, the sealing 1 is thereby squeezed together and expand in radial direction. This again will contribute to an increase in pressure from the sealing 1 against the inside of the base tube 11, which contributes to an improvement of the sealing.
• the support rings 2 and the5 shaping between the support rings 2 and the sealing 1 prevents, however, the sealings from being squeezed, scoured or sucked out of the groove the sealing 1 is located in and through the valve openings 12 when the sealing 1 is exposed to these.
• the support rings 2 and the shaping between the support rings 2 and the sealing 1 will prevent the sealing 1 from being displaced relative to or be-0 ing twisted out of the groove the sealing 1 lies in.
• the sealing and the support rings 2 are provided with a tongue-and-groove configuration, e.g. in the form of elevations 13 or "wings" on each side in axial direction of the sealing 1 which match corresponding grooves in the support rings 2 (see fig. 4 and 5), which contribute to holding the sealing 1 in correct location between the support rings 2, both with a view to prevent sucking out and with a view to preventing the sealing 1 from twisting relative to the support rings 2.
• Other configurations com- prise dovetail 2, U-shaped groove, V-shaped groove, drop-shaped groove, etc., depending on what is regarded being optimal for every single case.
• the support rings 2 are provided with a lip which partly overlies the sealing 1 (see fig. 4 and 5).
• the support rings 2 can possibly be shaped in such a way that the support rings 2 partly encircles the sealing 1. Such designs contribute to an even greater extent to holding the sealing 1 in place between the support rings 2.
• the support rings 2 and the locking rings 3 are designed such that the support rings 2 are held in place between the locking rings 2, e.g. by the locking rings 3 comprising key-shaped lips which project partly over the support rings 2 and thereby prevent the support ring 2 in bulging too much or bouncing out of its allocated position between the locking rings 3 (see fig. 4 and 5).
• the sealing device 10 vil function as a scraper against the inside of the base tube 11 , to thereby ensure that the sealing surface between the sealing device 10 and the base tube 11 stay free from cement and other unwanted particles.
• salt may crystallize out and settle around the sealing.
• the sealing device will also function as a scraper, without the sealing itself being cut or get damaged from the salt crystals.
• the strenght and durability of the sealing device 10 may further be improved by providing the cementing valve with oval ventilation ports 12 (see fig. 2-4). By giving the valve port 12 an oval shaping, the distribution of tension in the base tube 11 vil be improved, something which result in considerably improved tensile strength.
• valve port 12 may with advantage be designed as an embrasure, so that the edge the sealing 1 bends around get less sharp.
• a favourable taper angle has turned out to be approximately 20°.
• the inside of the valve port 12 is somewhat rounded.
• the sealing device 10 can be adapted to the environment and the loadings the cementing valve shall be subjected to, by adapting the support rings 2 and the sealings 1 materials and possibly also design to the individual instances of use and conditions of use.
• the sealing device 10 may also be retrofit on existing equipment which need robust and maintenancefree sealings.
• the present invention provides a stronger, maintenancefree and durable sealing device.
• the support rings 2 and the locking rings 3 are configured in such a way that they can take up more of the mechanical forces the sealing 1 is subjected to, by the fact that the configuration with support rings 2 and locking rings 3 ensures that the sealing 1 is held better in place, and by the fact that the sealing 1 may be threaded of the sleeve 7 without the sealing 1 need to be flexible, far more materials can be used for the sealing 1.
• the sealing device 10 in any case configured in such a way that the strenghts, service life and usefulness is radically improved relative to todays conventional solutions.

Landscapes

• Geology (AREA)
• Life Sciences & Earth Sciences (AREA)
• Engineering & Computer Science (AREA)
• Mining & Mineral Resources (AREA)
• Environmental & Geological Engineering (AREA)
• Fluid Mechanics (AREA)
• Physics & Mathematics (AREA)
• General Life Sciences & Earth Sciences (AREA)
• Geochemistry & Mineralogy (AREA)
• Gasket Seals (AREA)
• Details Of Valves (AREA)
• Sealing Devices (AREA)
• Mechanical Sealing (AREA)

Priority Applications (7)

Applications Claiming Priority (2)

Publications (1)

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Family Applications (1)

Country Status (9)

Citations (3)

Family Cites Families (13)

• 2006
  • 2006-07-14 NO NO20063285A patent/NO20063285A/no unknown
• 2007
  • 2007-07-09 EP EP07793919.7A patent/EP2041392B8/en not_active Not-in-force
  • 2007-07-09 BR BRPI0713246-8A patent/BRPI0713246A2/pt not_active Application Discontinuation
  • 2007-07-09 DK DK07793919.7T patent/DK2041392T3/en active
  • 2007-07-09 MX MX2009000011A patent/MX2009000011A/es active IP Right Grant
  • 2007-07-09 US US12/308,654 patent/US20100187763A1/en not_active Abandoned
  • 2007-07-09 WO PCT/NO2007/000267 patent/WO2008020759A1/en active Application Filing
  • 2007-07-09 CA CA002656827A patent/CA2656827A1/en not_active Abandoned
• 2008
  • 2008-12-17 TN TNP2008000524A patent/TNSN08524A1/en unknown

Patent Citations (3)

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