Compensated deep propagation measurements with differential rotation
US9784880B2 · kind B2 · utility
Assignee
Inventor
Key dates
| Filing date | Nov 20, 2014 |
| Grant date | Oct 10, 2017 |
| Priority date | — |
| Expiry date | Jul 11, 2035 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01V3/26
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A method for making downhole electromagnetic logging while drilling measurements includes rotating an electromagnetic logging while drilling tool in a subterranean wellbore. The logging tool includes a first transmitter and a first receiver deployed on a first sub and a second transmitter and a second receiver deployed on a second sub. Rotating the logging tool causes the first and second subs to rotate at different rates. A plurality of electromagnetic voltage measurements are acquired from the first and second receivers while rotating. The acquired voltage measurements are processed to compute harmonic coefficients which are mathematically rotated to obtain rotated coefficients. Ratios of selected ones of the rotated coefficients are processed to compute gain compensated measurement quantities.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.