Pre-stressed annular sealant and method of creating a durable seal in a well bore annulus
US7712530B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | Aug 9, 2007 |
| Grant date | May 11, 2010 |
| Priority date | — |
| Expiry date | Aug 22, 2027 |
Classification
- Technology area (CPC E)Fixed Constructions
- CPC primaryE21B33/14
- WIPO fieldBasic materials chemistry
- WIPO sectorChemistry
Abstract
A pre-stressed annular sealant and method of creating a durable seal in a well bore annulus which is based on hydraulic cement that is designed to be easily pumped and placed into a casing-wellbore annulus, to set into a hardened mass, and to then undergo post-set crystal growth and phase changes in the crystalline matrix to combat inherent volumetric shrinkage and to create internally-generated compressive stress in the cement matrix. This internally-generated compressive pre-stressing compensates for tensile stress induced by well operations. The tensile stress must be greater in magnitude than the magnitude of the compressive pre-stress plus the magnitude of the cement's tensile strength before the cement sheath will fail in tension. This expansion and pre-stressing also creates significantly higher shear bond strengths than those developed with ordinary hydraulic cement.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.