Riser clamp

1. A riser clamp to carry fluid pipes in parallel with and spaced apart from an external surface coated steel riser providing communication between a well head at a seabed and a surface vessel, the riser clamp comprising:

a pair of halves for frictional, non-rotatable fixation to the external surface coated steel riser;

the pair of halves having an external facing surface and an internal abutment surface made of a fiber reinforced composite material to circumferentially bear against the external surface coated steel riser;

the pair of halves having radially outward projecting first and second flanges;

a pipe saddle located between the first and second flanges and extending radially outward from the external facing surface to a first saddle recess to carry a first fluid pipe spaced radially apart from the external surface coated steel riser;

a first clamp connected with the pipe saddle to secure the first fluid pipe in the first saddle recess; and

an orbital strap to be positioned circumferentially about the pair of halves and located on the external facing surface between the pipe saddle and one of the first flange and the second flange, the orbital strap to circumferentially act on the pair of halves and thereby non-rotatably fix the pair of havles to the extenral surface coated steel riser in response to tensioning the orbital strap.

2. A riser clamp according to claim 1 , wherein the pair of halves are metal.

3. A riser clamp according to claim 1 , wherein the pair of halves are manufactured of fiber reinforced composite material.

4. A riser clamp according to claim 1 , wherein the internal abutment surface is formed by a lining of the fiber reinforced composite material having a thickness in the order of magnitude 2-4 mm.

5. A riser clamp according to claim 1 , wherein the fiber reinforced composite material has fibers of one or more fiber materials chosen among, carbon fiber, aramid fiber and glass fiber.

6. A riser clamp according to claim 1 , wherein the fiber reinforced composite material has a resin matrix chosen among; vinyl ester, polyester and epoxy.

7. A riser clamp according to claim 1 , wherein the orbital strap comprises shackles having tightening screws.

8. A riser clamp according to claim 1 , wherein the internal surface of the riser clamp has a texture, random or repetitive.

9. The apparatus of claim 1 , further comprising:

a second saddle recess formed on the pipe saddle to carry a second fluid pipe spaced radially apart from the externally facing surface and the riser; and

a second clamp connected with the pipe saddle to secure the second fluid pipe in the second saddle recess.

10. An apparatus, comprising:

a riser for providing fluid communication between a well head at a seabed and a surface vessel;

a riser clamp having an internal surface circumferentially engaging the riser, an external facing surface, and a pair of radially outward projecting flanges;

a pipe saddle located between the radially outward projecting flanges and extending radially outward from the external facing surface, the pipe saddle having a first saddle recess spaced radially apart from the external facing surface and the riser;

a first pipe extending parallel with the riser and abutting the first saddle recess;

a first clamp securing the first pipe in the first saddle recess; and

a tensioned band positioned circumferentially about the riser clamp and located on the external facing surface between the pipe saddle and one of the radially outward projecting flanges, whereby the tensioned band is circumferentially acting on the riser clamp to non-rotatably fix the riser clamp and the first pipe to the riser.

11. The apparatus of claim 10 , wherein an interface between the internal surface and the riser has a friction coefficient greater than a friction coefficient of an interface between the tensioned band and the riser clamp.

12. The apparatus of claim 10 , wherein the internal surface is made of a fiber reinforced composite material.

13. The apparatus of claim 10 , further comprising:

a second saddle recess formed on an opposite side of the pipe saddle from the first saddle recess;

a second pipe extending parallel with the riser and abutting the second saddle recess; and

a second clamp securing the second pipe in the second saddle recess.

14. The apparatus of claim 13 , wherein an interface between the internal surface and the riser has a friction coefficient greater than a friction coefficient of an interface between the tensioned band and the riser clamp.

15. The apparatus of claim 14 , wherein the first saddle recess has a radius of curvature different from a radius of curvature of the second saddle recess.

16. An apparatus, comprising:

a riser clamp non-rotatably fixed to an external coated surface of a riser, the riser clamp having an internal surface substantially circumferentially engaging the external coated surface of the riser, an external facing surface, and a first flange and a second flange spaced apart and extending radially outward;

a first pipe saddle extending radially outward from the external facing surface, the first pipe saddle having a first saddle recess spaced radially apart from the external facing surfance and the riser;

a first pipe extending parallel with the riser and abutting the first saddle recess; and

an orbital strap positioned circumferentially about the riser clamp and located on the external facing surface between the first pipe saddle and one of the first flange and the second flange, the orbital strap tensioned to secure the riser clamp to the riser, wherein an interface between the riser clamp and the orbital strap has a lower friction coefficient than an interface between the internal surface of the riser clamp and the riser.

17. The apparatus of claim 16 , further comprising:

a first clamp hingedly connected to the first pipe saddle and securing the first pipe in the first saddle recess;

a second pipe saddle extending outward from the extermal facing surface of the riser clamp, the second pipe saddle comprising a second saddle recess spaced apart from the riser and a third saddle recess spaced apart from the riser and located on an opposite side of the second pipe saddle from the second saddle recess;

a second pipe extending parallel with the riser and abutting the second saddle recess;

a second clamp hingedly connected to the second pipe saddle and securing the second pipe in the second saddle recess;

a third pipe extending parallel with the riser and abutting the third saddle recess; and

a third clamp hingedly connected to the second pipe saddle and securing the third pipe in the third saddle recess.

18. The apparatus of claim 16 , wherein the orbital strap comprises two tensioning bands that are positioned on the external facing surface on opposite sides of the pipe saddle from one another.

19. The riser clamp of claim 1 , wherein the orbital strap comprises two tensioning bands that are positioned on the external facing surface on opposite sides of the pipe saddle from one another.