Objective oriented methods for NMR log acquisitions for estimating earth formation and fluid properties
US6972564B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Nov 5, 2002 |
| Grant date | Dec 6, 2005 |
| Priority date | — |
| Expiry date | Mar 10, 2023 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01V3/32
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
An objective oriented NMR logging method selects pulse sequences over a plurality of frequencies from a set of building blocks. The building blocks include trainlet sequences wherein each trainlet comprises an excitation pulse and a plurality of refocusing pulses, the total length of a trainlet being typically less than 10 ms. Another building block is a short CPMG or modified CPMG sequence and yet another building block is a regular CPMG or modified CPMG sequence. The modified CPMG sequences may have refocusing pulses with a tipping angle less than 180° to reduce the power consumption. Based on the logging objective (formation evaluation or FE, FE plus hydrocarbon typing, FE plus gas evaluation) the building blocks are combined at a plurality of frequencies with different wait times and TEs.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.