Method and apparatus for the measurement of the electrical resistivity of geologic formations employing modeling data
US6393363B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | Dec 15, 2000 |
| Grant date | May 21, 2002 |
| Priority date | — |
| Expiry date | Dec 15, 2020 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01V3/30
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
Provided are a method, a computer program product and a system, to measure characteristics of a geologic formation, such as hydrocarbon reservoirs, that employs modeling data to remove unwanted information from a signal carrying information concerning the geologic formation. This allows obtaining accurate information concerning the resistivity of geologic formations in which a borehole has been formed and encased with a conductive liner, such as a steel casing. Specifically, it was recognized that a magnetic field produced within a borehole that has been cased is substantially similar to magnetic field produced from a borehole that was not cased, i.e., the spatial distribution and orientation to the two aforementioned magnetic fields are the same, differing only by a constant related to the casing attenuation factor. The magnetic field outside of the cased borehole is reduced in amplitude by an attenuation factor associated with the liner. Thus, the magnetic field produced at a point outside of the liner is a function of the product of term for the attenuation factor of the liner, ke and a term for the response of the geologic formation, ƒ. Both terms are independent of the ot…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.