Method of determining the porosity of an underground formation being drilled
US4981036A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jun 28, 1989 |
| Grant date | Jan 1, 1991 |
| Priority date | — |
| Expiry date | Jun 28, 2009 |
Classification
- Technology area (CPC E)Fixed Constructions
- CPC primaryE21B49/003
- WIPO fieldCivil engineering
- WIPO sectorOther fields
Abstract
The invention relates to a method of determining the porosity of an undergound formation being drilled by a rotating drill bit mounted at the lower end of a drill string. The torque (TOR) and the weight (WOB) applied on the bit when drilling the underground formation are measured; the effect of the geometry of the drill bit on the torque and weight on bit response is determined; the porosity (phi) of the formation being drilled is derived from the measured TOR and WOB taking into account the effect of the geometry of the drill bit. Preferentially, the porosity phi is determined from the following equation: EQU TOR=(k.sub.1 +k.sub.2.phi)WOB.sup.a where k.sub.1, k.sub.2 and a are parameters characteristic of the geometry of the drill bit.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.