Self adaptive cement systems

• US 8,469,095 B2
• Filed: 09/28/2010
• Issued: 06/25/2013
• Est. Priority Date: 05/14/2003
• Status: Expired due to Fees

• Current Assignee: Schlumberger Technology Corporation (Schlumberger NV)
• Original Assignee: Schlumberger Technology Corporation (Schlumberger NV)
• Inventors: Le Roy-Delage, Sylvaine, Martin-Beurel, Muriel, Dismuke, Keith, Nelson, Erik
• Primary Examiner(s): MARCANTONI, PAUL D
• Application Number:
  US12/892,543
• Publication Number:
  US 20110067868A1
• Time in Patent Office: 1,001 Days
• Field of Search: 166/293
• 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 casing inside the borehole of a well, or inside a previously installed casing;

(ii) pumping an aqueous hydraulic cement slurry comprising a polymethacrylate super-absorbent polymer having residual water-absorption properties after the setting of the cement, wherein the polymer is added at a concentration between 0.05% and 3.2% by weight of cement, and the polymer particle size is between 10 μ

m and 1500 μ

m;

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

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

2. The method of claim 1, wherein the super-absorbent polymer is dry-blended with the cement.

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

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

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

6. The method of claim 1, wherein the cement slurry further comprises at least one additive selected from the group consisting of dispersing agents, fluid loss control agents, set retarders, set accelerators and anti-foaming agents.

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

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

(ii) pumping an aqueous hydraulic cement slurry comprising a polymethacrylate super-absorbent polymer having residual water-absorption properties after the setting of the cement, wherein the polymer is added at a concentration between 0.05% and 3.2% by weight of cement, and the polymer particle size is between 10 μ

m and 1500 μ

m; and

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

8. The method of claim 7, 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.

9. The method of claim 7, wherein the cementing process is remedial cementing, performed in either a cased or open hole.

10. The method of claim 7, wherein the cement comprises Portland cement.

11. The method of claim 7, wherein the cement slurry further comprises one or more members selected from the group consisting of dispersing agents, fluid-loss-control agents, set retarders, set accelerators and antifoaming agents.

12. A method of manufacturing a cement that will self-repair comprising dry blending a polymethacylate super absorbent polymer with a hydraulic 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, wherein the polymer is added at a concentration between 0.05% and 3.2% by weight of cement, and the polymer particle size is between 10 μ

m and 1500 μ

m.

13. The method of claim 12, 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.

14. The method of claim 12, wherein the viscosity of the pumpable cement slurry is below about 1000 MPa-s at a shear rate of 100 s⁻

1.