Silica composition for servicing subterranean wells

Patent metadata

Field	Value
Publication number	US-9790418-B2
Application number	US-201414535237-A
Country	US
Kind code	B2
Filing date	Nov 6, 2014
Priority date	Apr 9, 2009
Publication date	Oct 17, 2017
Grant date	Oct 17, 2017

Abstract

This invention relates to methods for servicing subterranean wells, in particular, fluid compositions and methods for remedial operations during which the fluid compositions are pumped into a wellbore and make contact with well cements placed during primary cementing or previous remedial cementing operations.

First claim

We claim:

1. A pumpable sealant composition for establishing hydraulic isolation in a cemented subterranean well, comprising:
a silica-particle suspension with no intrinsic cementitious properties which, upon exposure to multivalent ions, forms a gel.

2. The composition of claim 1 , wherein the subterranean well has been cemented with one or more members of the list comprising Portland cement, a lime/silica blend, a lime/pozzolan blend, calcium aluminate cement, Sorel cement, chemically modified phosphate ceramic and geopolymer.

3. The composition of claim 1 , wherein the silica particles comprise colloidal silica, fumed silica, or both.

4. The composition of claim 1 , wherein the silica particles have an average particle size (d 50 ) that is less than or equal to one micrometer.

5. The composition of claim 1 , further comprising a latex, titanium dioxide, manganese tetraoxide or combinations thereof having average particle size (d 50 ) less than or equal to one micrometer.

6. The composition of claim 1 , further comprising a pH buffer.

7. The composition of claim 1 , wherein the suspension has a pH between about 5 and about 11.

8. The composition of claim 1 , further comprising a chloride salt at a concentration below about 0.2 molar.

9. The composition of claim 1 , further comprising a multivalent-cation sequestering agent.

10. The composition of claim 8 , wherein the multivalent-cation sequestering agent is an amine, an amine derivative, or both.

Assignees

• Schlumberger Technology Corp

Inventors

• James Simon Gareth
• Michaux Michel
• Carelli Clara
• Le Roy-Delage Sylvaine

Classifications

• E21B33/138

  Plastering the borehole wall; Injecting into the formation · CPC title

• C09K8/50 Primary

  Compositions for plastering borehole walls, i.e. compositions for temporary consolidation of borehole walls (compositions for consolidating loose sand or the like around wells C09K8/56) · CPC title

• C09K8/428

  for squeeze cementing, e.g. for repairing · CPC title

• C04B28/18 Primary

  containing mixtures of the silica-lime type · CPC title

• C04B14/062

  Microsilica, e.g. colloïdal silica (preparing microsilica slurries or suspensions C04B18/148) · CPC title