SELF ADAPTIVE CEMENT SYSTEMS

• US 20110067868A1
• Filed: 09/28/2010
• Published: 03/24/2011
• Est. Priority Date: 05/14/2003
• Status: Active Grant

• Current Assignee: Schlumberger Technology Corporation (Schlumberger NV)
• Original Assignee: Schlumberger Technology Corporation (Schlumberger NV)
• Inventors: Nelson, Erik, Martin-Beurel, Muriel, Le Roy-Delage, Sylvaine, Dismuke, Keith
• Granted Patent: US 8,469,095 B2
• Time in Patent Office: Days
• US Class Current: 166/293
• CPC Class Codes: C04B 20/008 Micro- or nanosized fillers, e.g. micronised fillers with particle size smaller than that of the hydraulic binder colloidal silica C04B14/062 ; silica fume C04B18/146
• CPC Class Codes: C04B 2103/0051 Water-absorbing polymers, hydrophilic polymers
• CPC Class Codes: C04B 2103/0062 Cross-linked polymers
• CPC Class Codes: C04B 2103/12 Set accelerators
• CPC Class Codes: C04B 2103/22 Set retarders
• CPC Class Codes: C04B 2103/408 Dispersants
• CPC Class Codes: C04B 2103/46 Water-loss or fluid-loss reducers, hygroscopic or hydrophilic agents, water retention agents
• CPC Class Codes: C04B 2103/50 Defoamers, air detrainers
• CPC Class Codes: C04B 22/124 Chlorides of ammonium or of the alkali or alkaline earth metals, e.g. calcium chloride
• CPC Class Codes: C04B 24/2641 Polyacrylates; Polymethacrylates
• CPC Class Codes: C04B 24/2652 Nitrogen containing polymers, e.g. polyacrylamides, polyacrylonitriles
• CPC Class Codes: C04B 28/02 containing hydraulic cements other than calcium sulfates
• CPC Class Codes: C04B 40/0641 Mechanical separation of ingredients, e.g. accelerator in breakable microcapsules
• CPC Class Codes: C09K 8/467 containing additives for specific purposes

Abstract

A self-healing cement system includes cement, water and at least one additive that swells in contact with water from reservoir or from formation in the case of a structural failure in the set cement to provide a physical barrier in the zone of failure. Examples of such material include particles of super-absorbent polymer. These additives have the effect of making the cement self-healing in the event of physical failure or damage such as micro-annuli. The self healing property is produced by the contact of the water itself, the potential repair mechanism is thus activated if and when needed in case of start of loss of zonal isolation. Several super-absorbent polymers have been identified such as polyacrylamide, modified crosslinked poly(meth)acrylate and non-soluble acrylic polymers.

Claims

1. A method for maintaining zonal isolation in a subterranean well having a borehole comprising:

(i) installing a tubular body inside the borehole of the well, or inside a previously installed tubular body;

(ii) pumping aqueous cement slurry comprising a material having residual water-absorption properties after the setting of the cement;

(iii) allowing the cement slurry to set and harden;

(iv) in the event of cement-matrix or bonding failure, allowing the material to swell by being in contact with underground water, thereby restoring zonal isolation.

2. The method of claim 1, wherein said material is a super-absorbent polymer.

3. The method of claim 2, wherein the super-absorbent polymer is selected from the list consisting of polymethacrylate and polyacrylamide or a non-soluble acrylic polymers.

4. The method of claim 2, wherein the super-absorbent polymer is added to the slurry dry-blended with the cement

5. The method of claim 2, wherein the super-absorbent polymer is added at a concentration between 0.05% and 3.2% by weight of cement.

6. The method of claim 1, wherein the cement slurry further comprises a salt.

7. The method of claim 2, wherein the super-absorbent polymer is added under the form of particles ranging from 10 to 1500μ

.

8. The method of claim 1, whereby the material is provided in a capsule that releases the material in response to exposure of the cement to at least one downhole parameter.

9. The method of claim 1, whereby the material is provided in a capsule that releases the material when the cement matrix cracks.

10. The method of claim 1, wherein the cement slurry further comprises at least one additive selected from the list consisting of dispersing agent, fluid loss control agent, set retarder, set accelerator and anti-foaming agent.

11. A method for cementing a subterranean well having a borehole, comprising:

(i) installing a tubular body inside the borehole of the well, or inside a previously installed tubular body;

(ii) pumping an aqueous cement slurry comprising a material having residual water-absorption properties after the setting of the cement; and

(iii) allowing the cement slurry to set and harden inside the annular region.

12. The method of claim 11, wherein the cementing process is primary cementing, and the cement slurry is either pumped down the interior of the tubular body and up through the annular region, or down the annular region and up the interior of the tubular body.

13. The method of claim 11, wherein the cementing process is remedial cementing, performed in either a cased or open hole.

14. The method of claim 11, wherein the cement comprises one or more members of the list comprising Portland cement, calcium aluminate cement, fly ash, blast furnace slag, lime-silica blends, geopolymers, Sorel cements and chemically bonded phosphate ceramics.

15. The method of claim 11, wherein the cement slurry further comprises one or more members of the list comprising dispersing agents, fluid-loss-control agents, set retarders, set accelerators and antifoaming agents.

16. The method of claim 11, wherein the tubular body comprises one or more members of the list comprising drillpipe, casing, liner and coiled tubing.

17. A method of manufacturing a cement that will self-repair when comprising dry blending a super absorbent polymer with cement, adding water in sufficient quantity so as to form a pumpable cement slurry, pumping the cement slurry in a wellbore, allowing the cement slurry to set, wherein in case of failure of the set cement, said set cement is repairing itself by allowing the super-absorbent polymer to swell when contacted by underground water.

18. The method of claim 17 is wherein the super-absorbent polymer is provided in a capsule that releases the material in response to exposure of the cement to at least one downhole parameter.

19. The method of claim 17, wherein the super-absorbent polymer is added under the form of particles ranging from 10 to 1500μ

.

20. The method of claim 17, wherein the viscosity of the pumpable cement slurry is below about 1000 mPa-s at a shear rate of 100 s⁻

1.