Multi-stage cementing tool

1. A cementing tool comprising:

an outer housing defining a central flow passage and a plurality of housing flow ports through a wall thereof;

an opening sleeve having a first opening sleeve face and a second opening sleeve face exposed to pressure in the outer housing, the first opening sleeve face having a greater surface area than the second opening sleeve face so that the pressure in the outer housing creates a pressure differential between the first opening sleeve face and the second opening sleeve face sufficient to move the opening sleeve from a first position covering the plurality of housing flow ports to a second position in which flow through the plurality of housing flow ports is permitted; and

an opening seat defined on the opening sleeve configured to receive an opening plug displaced into the outer housing, the opening sleeve also being movable from the first to the second position as a result of the opening plug engaging the opening seat and an application of pressure above the opening seat in the outer housing.

2. The cementing tool of claim 1 , the opening sleeve having a plurality of fluid openings therethrough communicated with the housing flow ports in the outer housing to permit flow therethrough into an annulus defined by the outer housing and a well bore wall in the second position of the opening sleeve.

3. The cementing tool of claim 1 , the opening sleeve being movable from the second position to a third position in the outer housing to prevent flow through the housing flow ports in the outer housing.

4. The cementing tool of claim 3 , further comprising a closing seat positioned in the opening sleeve, the closing seat configured to engage a closing plug delivered into the outer housing after the opening sleeve has moved to the second position, the opening sleeve movable to the third position upon an application of pressure in the outer housing above the closing plug.

5. The cementing tool of claim 1 , further comprising a closing sleeve detachably connected in the outer housing, the closing sleeve movable from a first position in the outer housing to a second position in the outer housing after the opening sleeve has moved to its second position, the closing seat positioned in the outer housing to prevent flow through the housing flow ports in the second position of the closing sleeve.

6. The cementing tool of claim 5 , the closing sleeve defining a closing seat therein configured to engage a closing plug displaced into the outer housing.

7. The cementing tool of claim 1 , further comprising a protective sleeve connected to the opening sleeve and extending upwardly therefrom, the protective sleeve defining a plurality of fluid apertures therethrough, the fluid apertures being communicated with an annular fluid passageway defined between the outer housing and the protective sleeve, the first sleeve face being open to the pressure in the outer housing through the plurality of fluid apertures and the annular fluid passageway.

8. A cementing tool comprising:

an outer housing connectable in a tubing string, the outer housing defining a central flow passage and having a plurality of housing flow ports through a wall thereof;

an opening sleeve movable in the outer housing from a first position in which flow through the housing flow ports is blocked to a second position in the outer housing in which flow from the central flow passage is permitted through the housing flow ports, the opening sleeve movable as a result either of differential pressure acting on the opening sleeve or an application of pressure in the outer housing to an opening plug that engages an opening seat on the opening sleeve; and

the opening sleeve being movable from the second to a third position in the outer housing in which flow through the housing flow ports from the central flow passage is prevented.

9. The cementing tool of claim 8 , further comprising first and second sleeve faces defined on the opening sleeve and open to tubular pressure, the first sleeve face having a greater surface area than the second sleeve face so that the differential-pressure sufficient to move the opening sleeve from the first position to the second position is created.

10. The cementing tool of claim 9 , further comprising a closing seat configured to engage a closing plug, the opening sleeve movable from the second to the third position upon the pressure in the outer housing reaching a predetermined pressure.

11. The cementing tool of claim 8 , the opening sleeve defining a plurality of fluid openings therethrough, the fluid openings in the opening sleeve being communicated with the housing flow ports only in the second position of the opening sleeve.

12. The cementing tool of claim 8 , the opening sleeve having a first outer diameter and a second outer diameter, the first outer diameter being greater than the second outer diameter, the cementing tool further comprising a stop piston positioned in an annulus defined between the second outer diameter and the outer housing, the stop piston being detachably connected to the outer housing and located to hold the opening sleeve in the second position.

13. The cementing tool of claim 12 , further comprising a closing seat in the opening sleeve configured to engage a closing plug, the stop piston configured to detach and permit the opening sleeve to move from the second to the third position upon an application of a predetermined pressure applied in the outer housing above the closing plug.

14. The cementing tool of claim 13 , further comprising a snap ring disposed about the opening sleeve on the second diameter thereof, the snap ring configured to radially expand in the second position of the opening sleeve.

15. A cementing tool comprising:

an outer housing defining a central flow passage therethrough and a plurality of housing flow ports in a wall thereof;

an opening sleeve detachably connected in the outer housing, the opening sleeve having first and second sleeve faces defined thereon open to tubular pressure and movable from a first position in which flow from the central flow passage through the housing flow ports is prevented to a second position in which flow from the central flow passage through the housing flow ports is permitted, the first sleeve face having a greater surface area than the second sleeve face such that the tubular pressure creates a differential pressure acting on the opening sleeve; and

an opening seat defined in the opening sleeve configured to receive an opening plug such that tubular pressure applied above the opening plug will move the opening sleeve from the first to the second position in the event that the differential pressure fails to move the opening sleeve from the first to the second position.

16. The cementing tool of claim 15 , the opening sleeve being movable from the second to a third position in which no flow is permitted from the central flow passage through the housing flow ports.

17. The cementing tool of claim 15 , further comprising a closing sleeve detachably connected in the outer housing above the opening sleeve, the closing sleeve movable from a first position to a second position in the outer housing to prevent flow through the housing flow ports after cement has been flowed through the housing flow ports in the outer housing.

18. The cementing tool of claim 17 , a lower end of the closing sleeve and the first opening sleeve face defining a space therebetween, the tubular pressure communicated to the opening sleeve face through the space.

19. The cementing tool of claim 15 further comprising a protective sleeve connected to the opening sleeve, the first sleeve face being open to tubular pressure through flow apertures defined in the protective sleeve.

20. The cementing tool of claim 15 further comprising a closing seat defined in the opening sleeve configured to receive a closing plug.