Drilling method
US7431106B2 · kind B2 · utility
Assignees
Inventors
Key dates
| Filing date | Jul 19, 2004 |
| Grant date | Oct 7, 2008 |
| Priority date | — |
| Expiry date | May 4, 2025 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC09K2208/18
- WIPO fieldBasic materials chemistry
- WIPO sectorChemistry
Abstract
A method of reducing formation breakdown during the drilling of a wellbore which method comprises: (a) circulating a drilling mud in the wellbore comprising (i) an aqueous or oil based fluid, (ii) at least one fluid loss additive at a concentration effective to achieve a high temperature high pressure (HTHP) fluid loss from the drilling mud of less than 2 ml/30 minutes and (iii) a solid particulate bridging material having an average particle diameter of 25 to 2000 microns and a concentration of at least 0.5 pounds per barrel; (b) increasing the pressure in the wellbore to above the initial fracture pressure of the formation such that fractures are induced in the formation and a substantially fluid impermeable bridge comprising the solid particulate bridging material and the fluid loss additive(s) is formed at or near the mouth of the fractures thereby strengthening the formation; (c) thereafter continuing to drill the wellbore with the pressure in the wellbore maintained at above the initial fracture pressure of the formation and below the breakdown pressure of the strengthened formation.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.