Full bore valve for downhole use

1. A downhole tool comprising:

a body having a bore formed therethrough and at least one end adapted to threadably engage one or more tubulars;

a sliding sleeve at least partially disposed in the body, the sliding sleeve adapted to move between a first position and a second position within the body;

a valve assembly comprising a valve member having an arcuate cross section wherein the valve member is adapted to pivot between an open and closed position within the body; and

a valve seat disposed in the body, the valve seat having a complimentary arcuate cross-section adapted to provide a fluid tight seal with the valve member,

wherein an interface between the valve member and the valve seat, in the closed position, is angled relative to the longitudinal centerline of the body, such that, proceeding radially outward, the interface extends away from a vertex of the arcuate cross section of the valve member, and

wherein the angle of the interface is between 1 degree and 89 degrees relative to the longitudinal centerline of the body.

2. The tool of claim 1 , wherein the sliding sleeve in the first position maintains the valve member in the open position.

3. The tool of claim 2 , wherein the valve member is disposed between the sliding sleeve and the body and wherein at least a portion of the sliding sleeve is disposed concentrically within the valve seat.

4. The tool of claim 1 , wherein the sliding sleeve in the second position permits the valve member to pivot to the closed position.

5. The tool of claim 1 , wherein the valve member is constructed of a frangible material.

6. The tool of claim 1 , wherein the valve member is constructed of a material selected from the group consisting of cast iron, cast aluminum, and ceramic.

7. The tool of claim 1 , wherein the valve member is constructed of a material soluble in a solvent selected from the group consisting of water, organic acids, inorganic acids, organic bases, inorganic bases, and organic solvents.

8. The tool of claim 1 , further comprising a pivot pin and helical extension spring, wherein the helical extension spring urges the valve member from the open position to the closed position.

9. The tool of claim 1 , wherein the valve member pivots along an arc of from about 85 degrees to about 95 degrees between the open and closed positions.

10. The tool of claim 1 , further comprising a hinge extension that is integral to the valve seat, wherein the valve member is pivotally coupled to the hinge extension.

11. The tool of claim 1 , further comprising a valve holder including an annular section disposed in the body and a hinge extension extending from the annular section, wherein the annular section is fixedly coupled to the valve seat and the valve member is pivotally coupled to the hinge extension.

12. The tool of claim 1 , further comprising a sheer pin received by the sliding sleeve and the body when the sliding sleeve is in the first position, wherein the sheer pin is configured to temporarily maintain the sliding sleeve in the first position.

13. A downhole tool comprising:

a body having a bore formed therethrough and at least one end adapted to threadably engage one or more tubulars;

a valve assembly comprising a valve member having an arcuate cross section, wherein the valve member is adapted to pivot between an open position and a closed position within the body, wherein the valve assembly incorporates an integral valve seat having a complimentary arcuate cross section adapted to provide a fluid tight seal with the valve member; and

a sliding sleeve at least partially disposed in the body, the sliding sleeve adapted to move between a first position and a second position within the body, wherein the sliding sleeve in the first position maintains the valve member in the open position, and wherein the sliding sleeve in the second position permits the valve member to pivot to the closed position,

wherein an interface between the valve member and the valve seat, in the closed position, is angled relative to the longitudinal centerline of the body, such that, proceeding radially outward, the interface extends away from a vertex of the arcuate cross section of the valve member, and

wherein the angle of the interface is between 1 degree and 89 degrees relative to the longitudinal centerline of the body.

14. The tool of claim 13 , wherein the valve member is constructed of a frangible material.

15. The tool of claim 14 , wherein the frangible material is a material selected from the group consisting of cast iron, cast aluminum, and ceramic.

16. The tool of claim 13 , wherein the valve member is constructed of a compound soluble in a solvent selected from the group consisting of water, organic acids, inorganic acids, organic bases, inorganic bases, and organic solvents.

17. The tool of claim 13 , further comprising a hinge extension that is integral to the valve seat, wherein the valve member is pivotally coupled to the hinge extension.

18. The tool of claim 13 , further comprising a valve holder including an annular section disposed in the body and a hinge extension extending from the annular section, wherein the annular section receives the valve seat at least partially therein and the valve member is pivotally coupled to the hinge extension.

19. A method for testing a well, comprising:

installing a casing string within a wellbore, the string comprising one or more sections of casing and one or more tools wherein each tool comprises:

a body having a bore formed therethrough and at least one end adapted to threadably engage one or more tubulars;

a valve assembly comprising a valve member having an arcuate cross section wherein the valve member is adapted to pivot between an open and closed position within the body;

a sliding sleeve at least partially disposed in the body, the sliding sleeve adapted to move between a first position and a second position within the body wherein the sliding sleeve in the first position maintains the valve member in the open position and wherein the sliding sleeve in the second position permits the valve member to pivot to the closed position;

a valve seat disposed in the body, the valve seat having a complimentary arcuate cross-section adapted to provide a fluid tight seal with the valve member,

wherein an interface between the valve member and the valve seat, in the closed position, is angled relative to the longitudinal centerline of the body, such that, proceeding radially outward, the interface extends away from a vertex of the arcuate cross section of the valve member, and

wherein the angle of the interface is between 1 degree and 89 degrees relative to the longitudinal centerline of the body;

stabilizing the wellbore by passing cement through the casing string, said cement filling an annular region between the casing swing and the wellbore;

pressure testing the casing swing using a hydraulic or pneumatic test fluid;

fracturing the cement surrounding the casing swing using hydraulic pressure, wherein the fracture occurs proximate to a hydrocarbon bearing interval;

displacing the sliding sleeve in a tool, thereby permitting the valve assembly in the tool to move to a second position; and

pressure testing the casing string above the tool using a hydraulic or pneumatic test fluid.

20. The tool of claim 19 , wherein the valve seat is integral to the valve assembly.