NMR log processing using wavelet filter and iterative inversion
US6225803A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Oct 29, 1998 |
| Grant date | May 1, 2001 |
| Priority date | — |
| Expiry date | Oct 29, 2018 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01R33/4625
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A method of nuclear magnetic resonance (NMR) well log processing. A wavelet decomposition of an NMR echo train is preformed. The resulting small scale coefficients, which may be discretely or continuously indexed by scale, in alternative embodiments, are windowed, and a first reconstruction generated therefrom by inverse wavelet transformation. The reconstructed signal is inverted and fit to a multiexponential model. Further refinements may be generated by iteratively decomposing the fitted signal at a preselected maximum scale, increasing at each iteration, generating a new coefficient by replacing the corresponding portion of the previous coefficient with the coefficient at the current scale, reconstructing the signal with the new coefficient, and fitting the signal so reconstructed to the relaxation time distribution.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.