Log inversion method for nuclear log data of earth formations
US9417354B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Feb 5, 2013 |
| Grant date | Aug 16, 2016 |
| Priority date | — |
| Expiry date | Jun 27, 2034 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01V5/06
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
Inverting nuclear log data for a geological formation surrounding a borehole involves acquiring nuclear log data for a borehole portion using a moveable nuclear logging tool and acquiring additional log data for the borehole portion using another logging device with superior resolution. Boundaries between adjacent zones are identified that exhibit an attribute of the geological formation to a detectably contrasting degree. From pre-acquired data describing one or more characteristics of the nuclear logging tool, a modeled log of the attributes is generated over the borehole portion, and a zone response is calculated from the pre-acquired data for each zone by using the boundaries to define an initial measure of the depth of each zone and ascribing a value of the attribute in dependence on the depth of each zone. The attribute of each zone is then calculated by deconvolving the nuclear log data using the zone response to minimize the difference between the nuclear log data and the convolution of the zone response and the attribute.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.