National Oilwell Varco Denmark I/s

Nkt A/s

National Oilwell Varco Denmark L/s

Inger-Margrete Procida

Claus Dencker Christensen

Allan Boye Hansen

Keld V Poulsen

Martin Damgaard Christensen

Disclosed is an unbonded flexible pipe for subsea transportation of fluids. The pipe has a length and a centre axis and includes a plurality of layers including at least one polypropylene based layer including a modified polypropylene compound including: at least about 50% by weight of a base polypropylene (base PP) which consists of polypropylene including up to about 10% by weight of one or more co-monomers other than propylene, and at least about 1% by weight of a plastomer including a propylene and at least one co-monomer other than propylene.

Unbonded flexible pipe

An unbonded flexible pipe for offshore fluid transportation is disclosed. The pipe includes from inside and outwards a sealing sheath, a pressure armor layer, at least one tensile armor layer, at least one support layer and an extruded external protective polymer sheath. The at least one support layer includes at least one support strip which is helically wound with a winding angle &#x3b1; of at least about 80 degrees to the longitudinal center axis to provide strip windings along the length of the pipe and the at least one support strip includes a thermoplastic vulcanizate (TPV).

The invention relates to an unbonded flexible pipe with a longitudinal axis and which comprises from inside outwards a carcass formed by metal windings with gaps between neighboring windings, at least one covering tape and an inner sealing sheath of a polymer extruded onto the covering tape. The covering tape is helically wound with a winding direction defining a tape length direction and a tape width direction perpendicular to the tape length direction. The covering tape comprises lengthwise continuous filament yarns arranged in the tape length direction of the covering tape. The covering tape has a thickness direction perpendicular to the tape length direction. The warp yarns have a thickness determined in the thickness direction of the covering tape of about 100 &#x3bc;m or less, such as of about 50 &#x3bc;m or less, such as from about 5 to about 25 &#x3bc;m.

The invention relates to a flexible pipe comprising at least one polymer layer, and at least one armoring layer unbounded to said polymer layer, wherein at least one polymer layer is a cationic clay containing polymer layer of a polymer material comprising a polymer matrix and from about 0.1 to about 5% by weight of at least one cationic clay silicate. Preferred cationic clay silicates comprise kaolinite; smectite; Illite; chlorite; and synthetic cationic clays. The cationic clay silicate may e.g. be an organo-cationic clay. The cationic clay silicate may preferably be exfoliated and/or intercalated in the polymer matrix. The polymer layer may preferably comprise an inner liner, a thermally insulating layer, an anti-wear layer and/or an outer sheath or a sub-layer thereof.

Flexible pipe

The invention relates to an unbonded, flexible pipe having a length and comprising from inside out, a tubular inner sealing sheath, at least one metal armor layer and an outer sealing sheath of a sealing material. The unbonded, flexible pipe comprises at least one stiffened length section comprising a stiffening cover partially or totally surrounding the outer sealing sheath in the stiffened length section. The stiffening cover comprises a layer of a stiffening material having a flexural modulus which is higher than the flexural modulus of the sealing material, wherein the flexural modulus is determined according to ISO 178.

Unbonded, flexible pipe

The invention relates to a method of producing a flexible pipe comprising a metal carcass and an internal sealing sheath extruded onto the carcass, saidmethod comprising providing a metal carcass; heating an application section of said carcass, preferably using induction heating, to an application section temperature of at least 150&#xb0; C.; extruding a non-cross-linked polyethylene material comprising a peroxide having an activation temperature above 150&#xb0; C. onto said application section of said carcass; cross-linking the extrudedpolyethylene in a cross-linking zone by raising its temperature to at least the activation temperature of said peroxide by exposing the extruded polymer material to electromagnetic waves, with a wavelength of between 0.5 &#x3bc;m to 0.5 m, preferably infrared radiation; and cooling said cross-linked polyethylene material to obtain the internal sealing sheath.In a preferred embodiment the method comprises heating the application section to an application section temperature of between 30 and 5&#xb0; C. below the activation temperature of the peroxide.Preferred peroxides include butylcumyl peroxide, dicumyl peroxide, 2,5-Dimethyl-2,5-di(tert-butylperoxy)hexyne-3,3,3,5,7,7-Pentamethyl-1,2,4-trioxepane, hydroperoxide, 2,5-dimethyl hexane 2,5-di-t-butyl peroxide, bis(t-butylperoxy isopropyl)benzene, t-butyl cumyl peroxide, di-t-butyl peroxide, 2,5-dimethyl hexine-3 2,5-di-t-butyl peroxide and butylhydroperoxide.A foil may be applied onto the metal carcass prior to the step of heating the metal carcass, the polyethylene material being extruded onto said foil.

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Hellerup, Denmark

Inger-Margrete Procida