Molded composite mandrel for a downhole zonal isolation tool

1. A composite mandrel comprising;

a filament-wound composite tube; and

composite material molded over the filament-wound composite tube;

wherein the composite material includes chopped fibers and a matrix of thermoset resin;

wherein the chopped fibers are arranged in layers upon the filament-wound composite tube, and the chopped fibers in each of the layers are randomly oriented along first and second orthogonal directions in said each of the layers;

wherein the composite mandrel is suitable for use as a central component of a down-hole tool; and

wherein the chopped fibers are parallel to planar interfaces between adjacent layers.

2. The composite mandrel as claimed in claim 1 , wherein the composite material has been molded over the filament-wound composite tube by shaping the composite material in a mold.

3. A composite mandrel comprising;

a filament-wound composite tube; and

composite material molded over the filament-wound composite tube;

wherein the composite material includes chopped fibers and a matrix of thermoset resin;

wherein the chopped fibers are arranged in layers upon the filament-wound composite tube and the chopped fibers in each of the layers are randomly oriented along first and second orthogonal directions in said each of the layers;

wherein the composite mandrel is suitable for use as a central component of a down-hole tool; and

wherein the composite mandrel is capable of sustaining tension in a longitudinal direction of 12,000 psi.

4. The composite mandrel as claimed in claim 3 , wherein the composite material has been molded over the filament-wound composite tube by shaping the composite material in a mold.

5. A composite mandrel comprising;

a filament-wound composite tube; and

composite material molded over the filament-wound composite tube;

wherein the composite material includes chopped fibers and a matrix of thermoset resin;

wherein the chopped fibers are arranged in layers upon the filament-wound composite tube, and the chopped fibers in each of the layers are randomly oriented along first and second orthogonal directions in said each of the layers;

wherein the composite mandrel is suitable for use as a central component of a down-hole tool; and

wherein the composite mandrel is capable of sustaining compression in a radial direction of 40,000 psi.

6. The composite mandrel as claimed in claim 5 , wherein the composite material has been molded over the filament-wound composite tube by shaping the composite material in a mold.

7. A composite mandrel comprising:

a filament-wound composite tube; and

composite material molded over the filament-wound composite tube;

wherein the composite material includes chopped fibers and a matrix of thermoset resin;

wherein the chopped fibers are arranged in layers u s on the filament-wound composite tube, and the chopped fibers in each of the layers are randomly oriented along first and second orthogonal directions in said each of the layers;

wherein the composite mandrel is suitable for use as a central component of a down-hole tool; and

which further includes a plug in one end of the filament-wound composite tube, and wherein the plug is sealed in the filament-wound composite tube by the composite material molded over the filament-wound composite tube.

8. The composite mandrel as claimed in claim 7 , wherein the composite material has been molded over the filament-wound composite tube by shaping the composite material in a mold.

9. A composite mandrel comprising:

a filament-wound composite tube; and

composite material molded over the filament-wound composite tube;

wherein the composite material includes chopped fibers and a matrix of thermoset resin;

wherein the chopped fibers are arranged in layers upon the filament-wound composite tube, and the chopped fibers in each of the layers are randomly oriented along first and second orthogonal directions in said each of the layers;

wherein the composite mandrel is suitable for use as a central component of a down-hole tool; and

wherein the composite material includes at least one sheet of the composite material wound over the filament-wound composite tube, and at least one strip of the composite material wound over said at least one sheet of the composite material, said at least one strip of the composite material forming a head on the composite mandrel.

10. The composite mandrel as claimed in claim 9 , wherein the composite material has been molded over the filament-wound composite tube by shaping the composite material in a mold.

11. A composite mandrel comprising:

a filament-wound composite tube; and

composite molding sheet material wound over and molded over the filament wound composite tube;

wherein the composite molding sheet material has been molded over the filament-wound composite tube by shaping the composite molding sheet material in a mold; and

wherein the composite molding sheet material includes chopped fibers and a matrix of thermoset resin, the chopped fibers are arranged in layers over the filament-wound composite tube, and the chopped fibers in each of the layers are randomly oriented along first and second orthogonal directions in said each of the layers;

wherein the composite molding sheet material includes at least one sheet of the composite molding sheet material wound over the filament-wound composite tube, and at least one strip of the composite molding sheet material wound over said at least one sheet of the composite molding sheet material and forming a head on the composite mandrel; and

wherein the composite mandrel is suitable for use as a central component of a down-hole tool.

12. The composite mandrel as claimed in claim 11 , wherein the chopped fibers are of constant length.

13. The composite mandrel as claimed in claim 11 , wherein the composite mandrel is capable of sustaining tension in a longitudinal direction of up to 12,000 psi.

14. The composite mandrel as claimed in claim 11 , wherein the composite mandrel is capable of sustaining compression in a radial direction of up to 40,000 psi.

15. The composite mandrel as claimed in claim 11 , wherein the filament-wound composite tube provides a lumen for the composite mandrel.

16. The composite mandrel as claimed in claim 15 , wherein an internal cavity of the filament-wound composite tube is threaded to receive a threaded plug for plugging the lumen of the composite mandrel.

17. The composite mandrel as claimed in claim 11 , which includes a plug in one end of the filament-wound composite tube, and wherein the plug is sealed in the filament-wound composite tube by the composite molding sheet material wound over and molded over the filament-wound composite tube.

18. A composite mandrel comprising:

a filament-wound composite tube; and

composite molding sheet material wound over and molded over the filament wound composite tube;

wherein the composite molding sheet material has been molded over the filament-wound composite tube by shaping the composite molding sheet material in a mold; and

wherein the composite molding sheet material includes chopped fibers and a matrix of thermoset resin, the chopped fibers are arranged in layers over the filament-wound composite tube, and the chopped fibers in each of the layers are randomly oriented along first and second orthogonal directions in said each of the layers;

wherein the composite molding sheet material includes at least one sheet of the composite molding sheet material wound over the filament-wound composite tube, and at least one strip of the composite molding sheet material wound over said at least one sheet of the composite molding sheet material and forming a head on the composite mandrel;

wherein the composite mandrel is suitable for use as a central component of a down-hole zonal isolation tool;

wherein the composite mandrel is capable of sustaining tension in a longitudinal direction of 12,000 psi; and

wherein the mandrel is capable of sustaining compression in a radial direction of 40,000 psi.

19. The composite mandrel as claimed in claim 18 , wherein the filament-wound composite tube provides a lumen for the composite mandrel.

20. The composite mandrel as claimed in claim 18 , wherein an internal cavity of the filament-wound composite tube is threaded to receive a threaded plug for plugging the lumen of the composite mandrel.

21. The composite mandrel as claimed in claim 18 , which includes a plug in one end of the filament-wound composite tube, and wherein the plug is sealed in the filament-wound composite tube by the composite molding sheet material wound over and molded over the filament-wound composite tube.