Method for improving the accuracy of NMR relaxation distribution analysis with two echo trains
US6069477A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Dec 19, 1997 |
| Grant date | May 30, 2000 |
| Priority date | — |
| Expiry date | Dec 19, 2017 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY02A90/30
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
The total porosity of a subterranean formation is calculated by summing the effective Porosity and the clay bound water (CBW) porosity. With the invention described in this patent, the distortion effects of clay bound water (CBW) porosity on the measurement of total porosity is filtered out. The effects will be more significant in slialy sand where the CBW porosity component of total porosity is abundant. The correct NMR transverse relaxation time (T.sub.2) spectra distribution is essential to a determination of capillary bound fluid (BVI) partial porosity and the Spectral Bulk Volume Irreducible (SBVI) model. The same data correction concept can be applied to make a meaningful comparison of well logs or laboratory core NMR data that are obtained with different interecho time (TE) sampling periods.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.