Patching of injection and production well annular casing leaks for restoring mechanical integrity
US6105673A · kind A · utility
Inventors
Key dates
| Filing date | Apr 20, 1998 |
| Grant date | Aug 22, 2000 |
| Priority date | — |
| Expiry date | Apr 20, 2018 |
Classification
- Technology area (CPC E)Fixed Constructions
- CPC primaryE21B33/138
- WIPO fieldBasic materials chemistry
- WIPO sectorChemistry
Abstract
A system of patching single and multiple casing leaks that occur in an injection well annulus, where there is direct communication from an outermost casing string to an original open-hole wellbore and adjacent earth strata. Preferred in this pumping system is a four-stage pump process employing four separate types of fluids. The first Injection Stage utilizes either H.sub.2 SiO.sub.3, Na.sub.2 in a solution of water forming Na.sub.2 SiO.sub.3 +H.sub.2 O (Sodium Metasilicate) or Na.sub.2 O*SiO.sub.2 (Sodium Silicate) in water. The second Injection Stage utilizes CaCl.sub.2 solution in water. These two solutions react in a double replacement chemical reaction to yield an aqueous phase and a solid phase. The third Injection Stage is then implemented, the same including a bentonite/high-density, high-solids, concentrated slurry additionally containing large plugging materials suspended therein. The Fourth Stage utilizes covalently bonded N.sub.2 in a gaseous state. After injection of the first Three Stages, N.sub.2 pressure is applied and the staged patching materials are moved into place at the casing hole(s), thread leak, packer leak, or perforation. Upon restriction, the materials r…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.