Stage cementing methods used in casing while drilling

1. A method of cementing a wellbore, comprising:

drilling the wellbore using an assembly comprising: a casing, a drilling member coupled to the casing, a float collar coupled to the casing, and a stage tool coupled to the casing;

opening ports in the drilling member;

performing a first cementing operation using the float collar and the open ports, wherein the float collar comprises a one way valve allowing flow of cement through the casing and into an annulus formed between the casing and the wellbore and preventing backflow of the cement into the casing;

opening the stage tool located in the casing;

performing second cementing operation through the open stage tool; and

drilling out the drilling member and the float collar.

2. The method of claim 1 , wherein the stage tool is opened using a plug.

3. The method of claim 1 , further comprising closing the stage tool.

4. The method of claim 3 , wherein the stage tool is closed using a plug.

5. The method of claim 1 , further comprising setting a packer prior to the second cementing operation.

6. The method of claim 1 , wherein the ports in the drilling member are opened by releasing a ball into the casing, landing the ball in the drilling member, and applying pressure to the drilling member.

7. The method of claim 6 , wherein landing the ball in the drilling member and applying pressure to the drilling member also displaces blades of the drilling member.

8. A method of cementing a wellbore, comprising:

drilling the wellbore using a drilling member coupled to a casing;

retrieving the drilling member from the casing;

pumping cement into the casing and through a one way plug;

launching the one way plug behind the cement;

pumping fluid behind the plug, thereby propelling the cement through the casing and into an annulus formed between the casing and the wellbore, wherein:

pumping is stopped to retain the plug within the casing, and

the plug anchors to the casing in response to the pumping stoppage, thereby retaining the cement in the annulus and preventing backflow of the cement into the casing.

9. The method of claim 8 , further comprising launching a bottom plug into the casing ahead of the cement, wherein the bottom plug is pumped through the casing and into the wellbore.

10. The method of claim 8 , wherein:

a stage tool is located in the casing,

the method further comprises launching an opening plug into the casing, and

the opening plug lands in the stage tool and opens the stage tool.

11. The method of claim 10 , wherein the opening plug is launched after pumping a predetermined volume of fluid so that the opening plug lands in and opens the stage tool while the top plug is still in the casing.

12. The method of claim 10 , wherein the opening plug free-falls to the stage tool.

13. The method of claim 10 , further comprising pumping cement through the open stage tool and into the annulus, wherein a closing plug is pumped behind the cement, lands in the stage tool, and closes the stage tool.

14. The method of claim 10 , wherein the opening and closing plugs are keyed to match respective profiles in the stage tool.

15. A method of cementing a wellbore, comprising:

drilling the wellbore using a drilling member coupled to a casing;

retrieving the drilling member from the casing;

deploying an electric, wire or slick line into the casing;

setting a packer in the casing using the line, wherein the packer has a one-way valve;

pumping cement through the casing and one-way valve and into an annulus formed between the casing and the wellbore, wherein the one-way valve retains the cement in the annulus and prevents backflow of the cement into the casing;

opening a stage tool located in the casing string using the line;

pumping cement through the casing and open stage tool and into the annulus; and

closing the stage tool using the line.

16. The method of claim 15 , further comprising drilling out the packer.

17. A method of cementing a wellbore, comprising:

drilling the wellbore using a drilling member coupled to a casing;

performing a first cementing operation;

opening a stage tool located in the casing, wherein:

the stage tool comprises a housing, a sleeve, an opening seat, and a closing seat,

a housing port is aligned with a sleeve port in the open position, and

a wall of the sleeve covers the housing port in a closed position;

performing a second cementing operation through the open stage tool; and

drilling out the seats, wherein the sleeve remains after drill out.