Well logging method for determining formation characteristics using pulsed neutron capture measurements
US7408150B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | Jun 25, 2007 |
| Grant date | Aug 5, 2008 |
| Priority date | — |
| Expiry date | Jun 25, 2027 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01V5/125
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A method for determining thermal capture cross-sections of formations surrounding an earth borehole, including the following steps: providing a logging device that is moveable through the borehole; transmitting, from the logging device, bursts of neutrons into the formations; detecting, at the logging device, resultant gamma ray counts, and deriving a measurement spectrum from the gamma ray counts; deriving a forward model comprising a combination of model exponential components having respective model decay times and model amplitudes; deriving an error function that depends on comparison between the forward model and the measurement spectrum; and determining, by regularized inversion, optimized exponential components of the model that substantially minimize the error function; the optimized exponential components being indicative of the thermal capture cross-sections of the formations.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.