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

Definitions

• the present invention relates to a method of operating a wellbore formed in an earth formation, the wellbore being provided with a tubular element in which a wellbore device is to be arranged such that the wellbore device is sealed to the inner surface of the tubular element, and whereby an elongate member is to be extended through the tubular element for carrying out a wellbore operation.
• the production tubing can be provided with one or more devices, such as surface- controlled subsurface safety valves, tubing hangers, landing nipples, packers and sliding side-doors. Some of these devices are retrievable and are sealingly installed in the string.
• the production tubing string is assembled from a plurality of tubular sections, whereby one or more landing nipples are incorporated in the string at each location in the string where such retrievable device is to be installed.
• each landing nipple corresponds to the dimensions of a respective one of the retrievable devices. Sealing of the retrievable device to the inner surface of the landing nipple is achieved by suitable seal elements, such as chevron type seals. In order to achieve adequate sealing, the seal surface portions of the landing nipples are often polished so as to provide a very smooth seal surface.
• a seal assembly of a production tubing is formed by the lower end part of the production tubing and is received in a polished bore receptacle (PBR) of a production packer arranged near the producing zone of the wellbore.
• the seal assembly is axially movable relative to the PBR to allow for thermal expansion/contraction of the production tubing.
• Tubular elements like production tubings and PBR' s, are also used to convey equipment for conducting downhole operations.
• the downhole equipment can be lowered on a wireline through the production tubing or through the PBR.
• Such operation involves movement of the wireline (which can be of several kilometres length) at high speed through the production tubing or PBR whereby the wireline scratches along the polished seal surfaces.
• the seal surfaces may become damaged so that adequate sealing of the device in the tubular element can no longer be guaranteed. In many instances such situation leads to serious limitations in operating the well, and may even compromise the safety of the well.
• a method of operating a wellbore formed in an earth formation the wellbore being provided with a tubular element in which a wellbore device is to be arranged such that the wellbore device is sealed to the inner surface of the tubular element, and whereby an elongate member is to be extended through the tubular element for carrying out a wellbore operation, the method comprising: extending the elongate member through the tubular element so as to carry out said wellbore operation; removing the elongate member from the tubular element;
• the invention also relates to a wellbore device for use in a wellbore formed in an earth formation whereby the wellbore is provided with a tubular element in which the wellbore device is to be arranged in a manner that the wellbore device is sealed to the inner surface of the tubular element, and whereby an elongate member is to be extended through the tubular element for carrying out a wellbore operation, the wellbore device being provided at the outer surface thereof with a swelleable seal susceptible of swelling upon contact with a selected fluid.
• the tubular element is a production tubing for transporting hydrocarbon fluid produced from the earth formation to surface, or a part thereof such as a landing nipple for the wellbore device.
• the wellbore device is, for example, a safety valve assembly for selectively controlling flow of hydrocarbon fluid through the production tubing.
• tubular element is a polished bore receptacle (PBR)
• wellbore device is a seal assembly of a production tubing for transporting hydrocarbon fluid produced from the earth formation, to surface.
• the swelleable seal swells upon contact with hydrocarbon fluid, and includes a material selected from natural rubber, nitrile rubber, hydrogenated nitrile rubber, acrylate butadiene rubber, poly acrylate rubber, butyl rubber, brominated butyl rubber, chlorinated butyl rubber, chlorinated polyethylene, neoprene rubber, styrene butadiene copolymer rubber, sulphonated polyethylene, ethylene acrylate rubber, epichlorohydrin ethylene oxide copolymer, ethylene-propylene-copolymer (peroxide crosslinked) , ethylene-propylene-copolymer (sulphur crosslinked) , ethylene-propylene-diene terpolymer rubber, ethylene vinyl acetate copolymer, fluoro rubbers, fluoro silicone rubber, and silicone rubbers .
• a material selected from natural rubber, nitrile rubber, hydrogenated nitrile rubber, acrylate butadiene
• Said material is suitably selected from EP(D)M rubber (ethylene-propylene-copolymer, either peroxide or sulphur crosslinked) , EPT rubber (ethylene-propylene-diene terpolymer rubber) , butyl rubber, brominated butyl rubber, chlorinated butyl rubber, and chlorinated polyethylene.
• EP(D)M rubber ethylene-propylene-copolymer, either peroxide or sulphur crosslinked
• EPT rubber ethylene-propylene-diene terpolymer rubber
• butyl rubber brominated butyl rubber
• chlorinated butyl rubber chlorinated polyethylene
• the swelleable seal suitably swells upon contact with water, and includes a material selected from NBR, HNBR, XNBR, FKM, FFKM, TFE/P or EPDM base rubber.
• said material suitably is a matrix material wherein a compound soluble in water is incorporated in the matrix material in a manner that the matrix material substantially prevents or restricts migration of the compound out of the swelleable seal and allows migration of water into the swelleable seal by osmosis so as to induce swelling of the swelleable seal upon migration of said water into the swelleable seal.
• Said compound suitably comprises a salt, for example at least 20 weight! salt based on the combined weight of the matrix material and the salt, preferably at least 35 weight% salt based on the combined weight of the matrix material and the salt.
• Fig. 1 schematically shows an embodiment of the wellbore device according to the invention
• FIG. 2 schematically shows detail A of the wellbore device of Fig. 1
• Fig. 3 schematically shows a longitudinal section of a tubular element to be used in conjunction with the wellbore device of Fig. 1;
• Fig. 4 schematically shows the wellbore device of Fig. 1 when arranged in the tubular element of Fig. 3.
• like reference numerals relate to like components.
• a surface-controlled subsurface safety valve assembly 1 (hereinafter: safety valve assembly 1) for selectively controlling flow of fluid through a wellbore (not shown) for the production of hydrocarbon fluid.
• the safety valve assembly 1 includes a tubular conduit 2 having a passage 4 for produced hydrocarbon fluid, the passage 4 being provided with valve 6 for selectively closing the passage 4.
• the valve 6 is controlled by a hydraulic control system of which only hydraulic control lines 8, 9 and plunger system 10 are schematically shown.
• the hydraulic lines 8, 9 are in fluid communication with the exterior of the safety valve assembly 1 via a port 11 provided in the wall of the tubular conduit 2.
• a locking mandrel 12 is provided at an upper portion of the safety valve assembly 1 for supporting and locking the safety valve assembly 1 in a production tubing referred to hereinafter.
• the safety valve assembly 1 is provided with two annular seals 14, 16 arranged at an axial distance from each other, whereby the port 11 is located between the annular seals 14, 16.
• Each annular seal 14, 16 includes a plurality of chevron type seals 18 and a swelleable seal 20 made of EPDM rubber which is susceptible of swelling upon contact with hydraulic oil to be used in the hydraulic control system for controlling the valve 6.
• the inner diameter of the landing nipple 22 is slightly larger than the outer diameter of the safety valve assembly 1 so as to allow axial movement of the safety valve assembly 1 through the landing nipple 22.
• the landing nipple 22 is internally provided with a locking profile 24 which is complementary to, and cooperates with, the profile of the locking mandrel 12 so as to allow the safety valve assembly 1 to be supported and locked in the landing nipple 22.
• the inner surface of the landing nipple 22 is provided with two polished annular surface portions 26, 28 of slightly smaller diameter than the remainder of the inner surface of the landing nipple 22.
• the polished surface portions 26, 28 are arranged such that annular seal 14 is located opposite polished surface portion 26, and annular seal 16 is located opposite polished surface portion 28 when the safety valve assembly 1 is locked in the landing nipple 22 by the cooperating locking mandrel 12 and locking profile 24.
• a port 30 is provided in the wall of the landing nipple 22 at a location between the polished surface portions 26, 28, the port 30 being in fluid communication with a hydraulic control unit (not shown) at surface via a hydraulic control line 32 extending along the outer surface of the production tubing. It is to be understood that the hydraulic control unit at surface, the control line 32, the port 30, the port 11, the hydraulic control lines 8, 9, and the plunger system 10 are all part of the hydraulic control system for controlling the valve 6.
• the safety valve assembly 1 is arranged in the landing nipple 22 of the production tubing. Hydrocarbon fluid is produced from the earth formation surrounding the wellbore and transported to surface via the production tubing. The produced hydrocarbon fluid thereby flows through the passage 4 of the safety valve assembly 1. If it is required to shut the well in, for example in case of an emergency situation, the valve 6 is induced to close under control of the hydraulic control system operated at surface. Leakage of hydrocarbon fluid along the outside of the safety valve assembly 1 is prevented by the annular seals 14, 16 which seal against the polished surface portions 26, 28 of the production tubing 22.
• the sealing function of the annular seals 14, 16 is still guaranteed by the swelleable seals 20 which swell by virtue of contact with the hydraulic oil present in the annular chamber defined by the outer surface of the safety valve assembly 1, the inner surface of the landing nipple 22, and the annular seals 14, 16.
• the seals 20, after swelling, extend into the irregularities formed at the damaged surface portions 26, 28 and thereby adequately seal the safety valve assembly 1 against the landing nipple 22.
• tubular element is a production tubing or a portion thereof, such as a landing nipple.
• Other useful applications include, for example, tubing hangers, packers, polished bore receptacles and sliding side-doors.

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)
• Sealing Material Composition (AREA)
• Pipe Accessories (AREA)
• Earth Drilling (AREA)
• Gasket Seals (AREA)
• Measurement Of Radiation (AREA)
• Analysing Materials By The Use Of Radiation (AREA)

Priority Applications (8)

Applications Claiming Priority (2)

Publications (1)

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ID=34930755

Family Applications (1)

Country Status (11)

Cited By (5)

Families Citing this family (10)

Citations (7)

Family Cites Families (5)

• 2005
  • 2005-10-25 DE DE602005011469T patent/DE602005011469D1/de active Active
  • 2005-10-25 WO PCT/EP2005/055526 patent/WO2006045794A1/en active Application Filing
  • 2005-10-25 US US11/666,259 patent/US20070257441A1/en not_active Abandoned
  • 2005-10-25 BR BRPI0517508A patent/BRPI0517508B1/pt not_active IP Right Cessation
  • 2005-10-25 CN CNA2005800356246A patent/CN101044294A/zh active Pending
  • 2005-10-25 AU AU2005298687A patent/AU2005298687C1/en active Active
  • 2005-10-25 CA CA2580376A patent/CA2580376C/en active Active
  • 2005-10-25 EA EA200700948A patent/EA011131B1/ru not_active IP Right Cessation
  • 2005-10-25 MY MYPI20055009A patent/MY140262A/en unknown
  • 2005-10-25 EP EP05801488A patent/EP1805391B1/en active Active
• 2007
  • 2007-05-25 NO NO20072697A patent/NO337536B1/no unknown

Patent Citations (7)

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