Apparatus and method for completing oil and gas wells

1. A method of drilling and completing a wellbore in a geological formation to produce hydrocarbons from a well comprising:

drilling the well with a drill bit attached to a casing;

pumping down a one-way valve into the casing with a well fluid; and

using the one-way valve to cement the casing into the wellbore while the drill bit remains attached to the casing.

2. A method of drilling and completing a wellbore, comprising:

drilling a wellbore with a drill bit attached to a casing having a one-way valve therein; and

using the one-way valve to cement the casing into the wellbore.

3. A method of drilling, comprising:

providing a tubular string having a casing portion, the casing portion having a cutting structure connected thereto;

operating the cutting structure and lowering the tubular string Into a wellbore of a desired depth; and

locating a downhole tool within the tubular string while the cutting structure remains attached to the casing.

4. The method of claim 3 , wherein the downhole tool comprises a valve.

5. The method of claim 4 , wherein the valve is a one-way valve.

6. The method of claim 5 , further comprising flowing cement through the one-way valve into an annulus between the outer diameter of the tubular string and the wellbore.

7. The method of claim 3 , wherein operating the cutting structure comprises rotating the cutting structure.

8. The method of claim 3 , wherein the cutting structure comprises a drill bit.

9. The method of claim 3 , further comprising placing cement within an annulus between an outer diameter of the tubular string and the wellbore.

10. The method of claim 3 , wherein locating comprises engaging a first latching member on the downhole tool having an interior surface of a second latching member with the tubular string.

11. The method of claim 3 , wherein the downhole tool is located by fluid.

12. The method of claim 3 , wherein the cutting structure is located at a lower end of the tubular string.

13. The method of claim 3 , wherein the locating includes positioning within the tubular string at a location.

14. The method of claim 13 , wherein locating the downhole tool comprises completely housing the downhole tool with the tubular string.

15. An apparatus for drilling and casing a wellbore, comprising:

a tubular string, at least a portion of the tubular string comprising casing;

a cutting member connected to the tubular string; and

a valve for segregating a first portion of an interior of the tubular string from a second portion of the interior of the tubular string.

16. The apparatus of claim 15 , wherein the valve is remotely locatable in the interior of the tubular string.

17. The apparatus of claim 16 , wherein the valve is remotely locatable by pressurized fluid.

18. The apparatus of claim 15 , wherein the cutting member is a drill bit.

19. The apparatus of claim 15 , wherein the cutting member is connected to a lower end of the tubular string.

20. The apparatus of claim 15 , wherein the valve is a one-way valve.

21. The apparatus of claim 15 , wherein the valve prevents fluid flow through the first portion of the tubular string.

22. The apparatus of claim 21 , wherein the fluid is cement.

23. The apparatus of claim 15 , wherein the valve is permanently located within the tubular string.

24. A method of drilling and completing a wellbore in a geological formation to produce hydrocarbons from a well comprising at least the following steps:

drilling the well with a retrievable drill bit attached to a casing;

removing the retrievable drill bit from the casing, wherein removing the retrievable bit from the casing comprises removing the entire drill bit which was used to drill the well from the casing;

pumping down a one-way valve into the casing with a well fluid; and

using the one-way valve to cement the casing into the wellbore.

25. A method of drilling and completing a wellbore in a geological formation to produce hydrocarbons from a well comprising at least the following steps:

drilling the well with a retrievable drill bit attached to a casing, wherein an extended outer diameter of the retrievable drill bit is at least as large as an outer diameter of the casing;

removing the retrievable drill bit from the casing;

pumping down a one-way valve into the casing with a well fluid; and

using the one-way valve to cement the casing into the wellbore.

26. A method of drilling and completing a wellbore in a geological formation to produce hydrocarbons from a well comprising at least the following steps:

drilling the well with a retrievable drill bit attached to a casing, wherein the retrievable drill bit is attached to a portion of the casing having an inner diameter that is as large as an inner diameter of the entire casing;

removing the retrievable drill bit from the casing:

pumping down a one-way valve into the casing with a well fluid; and

using the one-way valve to cement the casing into the wellbore.