Apparatus and method for determining density, porosity and fluid saturation of formations penetrated by a borehole
US6936812B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | May 24, 2004 |
| Grant date | Aug 30, 2005 |
| Priority date | — |
| Expiry date | May 24, 2024 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01V5/104
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A borehole logging system for determining bulk density, porosity and formation gas/liquid fluid saturation of formation penetrated by a borehole. Measures of fast neutron radiation and inelastic scatter gamma radiation, induced by a pulsed neutron source, are combined with an iterative numerical solution of a two-group diffusion model to obtain the formation parameters of interest. Double-valued ambiguities in prior art measurements are removed by using the iterative solution of the inverted two-group diffusion model. The system requires two gamma ray detectors at different axial spacings from the source, and a single neutron detector axially spaced between the two gamma ray detectors. The system can be embodied as a wireline system or as a logging-while-drilling system.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.