Downhole measurement of formation characteristics while drilling
US7458257B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Dec 19, 2005 |
| Grant date | Dec 2, 2008 |
| Priority date | — |
| Expiry date | Dec 5, 2026 |
Classification
- Technology area (CPC E)Fixed Constructions
- CPC primaryE21B49/081
- WIPO fieldCivil engineering
- WIPO sectorOther fields
Abstract
A method for determining a property of formations surrounding an earth borehole being drilled with a drill bit at the end of a drill string, using drilling fluid that flows downward through the drill string, exits through the drill bit, and returns toward the earth's surface in the annulus between the drill string and the periphery of the borehole, including the following steps: obtaining, downhole near the drill bit, a pre-bit sample of the mud in the drill string as it approaches the drill bit; obtaining, downhole near the drill bit, a post-bit sample of the mud in the annulus, entrained with drilled earth formation, after its egression from the drill bit; implementing pre-bit measurements on the pre-bit sample; implementing post-bit measurements on the post-bit sample; and determining a property of the formations from the post-bit measurements and the pre-bit measurements.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.