METHOD AND LIGHTWEIGHT COMPOSITION FOR SEALING PIPE AND WELLBORES

Abstract

The present invention provides a method and composition for sealing pipe in wellbores. The composition includes cement, water, gel and laminate particles. The laminate particles are added in a proportion to the cement to provide a weight to the slurry of between 12.5-14.5 pounds per gallon. The cement slurry is pumped down through pipe, such as casing, into the annulus and back up towards the surface. The cement slurry can extend from the producing formation to a location above the producing formation to form a seal. By utilizing the light weight cement slurry, the pipe such as casing can be sealed in a single stage operation.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a cross-sectional side view of a wellbore with casing extending through various geologic formations illustrating the method of the present invention, in accordance with a preferred embodiment.

FIG. 2 is a cross-sectional side view of a wellbore illustrating the method of the present invention in accordance with another embodiment.

Claims

1. A method of sealing pipe in a wellbore that penetrates a formation, comprising the steps of: a) providing a cement slurry comprised of cement, water, gel and laminate particles;b) locating the cement slurry in an annulus around the pipe;c) allowing the cement slurry to harden.

2. The method of claim 1 wherein the step of providing a cement slurry further comprises the step of providing the cement slurry at a weight of 12.5-14.5 pounds per gallon.

3. The method of claim 1 wherein the step of providing a cement slurry further comprises the step of providing a ratio of laminate particles to cement of 4:94 to 8:94 by weight.

4. The method of claim 1 wherein the step of providing a cement slurry further comprises the step of providing laminate particles of 250-2000 microns in size.

5. The method of claim 1 wherein the step of locating the cement slurry further comprises the step of locating the cement slurry in the annulus at the formation and above the formation in order to provide a seal and to protect the pipe from corrosive fluids in the wellbore.

6. The method of claim 1 wherein: a) the step of locating the cement slurry further comprises the step of locating the cement slurry, which is a first cement slurry, in the annulus above the formation;b) locating a second cement slurry that is heavier than the first cement slurry in the annulus at the formation.

7. The method of claim 6 wherein the step of locating a second cement slurry further comprises the step of providing a second cement slurry having a weight of between 13.5 to 16 pounds per gallon.

8. The method of claim 6 wherein the second cement slurry further comprises laminate particles.

9. The method of claim 1 wherein: the step of providing a cement slurry further comprises the steps of providing laminate particles of 250-2000 microns in size, the cement slurry having a weight 12.5-14.5 pounds per gallon and the ratio of laminate particles to cement being in between 4:94 to 8:94 by weight.

10. In a wellbore having a pipe that penetrates a formation, the pipe having an annulus, a sealing composition for use in the sealing of the pipe in the wellbore, comprising: cement, water, gel and laminate particles, the sealing composition located in the annulus.

11. The wellbore of claim 10 wherein the cement is selected from the group containing Type C or Type H Portland cement.

12. The wellbore of claim 10 wherein the sealing composition forms a slurry having a weight of 12.5-14.5 pounds per gallon.

13. The wellbore of claim 10 wherein the ratio of laminate particles to cement is 4:94 to 8:94 by weight.

14. The wellbore of claim 10 wherein the laminate particles are sized between 250-2000 microns.

15. The wellbore of claim 10, wherein: a) the sealing composition forms a slurry having a weight of 12.5-14.5 pounds per gallon;b) the ratio of laminate particles to cement is 4:94 to 8:94 by weight;c) the laminate particles are sized between 250-2000 microns.

16. The wellbore of claim 10 wherein the cement slurry extends in the annulus from the formation to a location above the formation so as to protect the pipe from corrosive fluids.

17. The wellbore of claim 10 wherein the cement slurry is a fist cement slurry and is located in the annulus above the formation, further comprising a second cement slurry that comprises cement, water, gel and laminate particles, the second cement slurry, being heavier than the first cement slurry, the second cement slurry being located in the annulus at the formation.