Efficient and accurate pseudo 2-D inversion scheme for multicomponent induction log data
US6618676B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Jan 29, 2002 |
| Grant date | Sep 9, 2003 |
| Priority date | — |
| Expiry date | Jan 29, 2022 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01V11/00
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A fast, efficient and accurate pseudo 2-D inversion scheme for resistivity determination of an anisotropic formation uses data from a tool (3DEX) comprising three transmitters and three corresponding receivers sampling the formation in a plurality of spatial directions. An initial model of the formation including invasion zones is obtained using a conventional multifrequency and/or multispacing logging tool. A pseudo 2-D inversion scheme combines an accurate full 2-D forward solution of the synthetic responses of the earth model with a 1-D approximation of the sensitivity matrix of the horizontally layered anisotropic background model. The timesaving compared to a regular 2-D inversion scheme can be tremendous. The applicability of this scheme is important in cases when borehole and near-zone effects do not allow an interpretation based on 1-D inversion. A comparison of the pseudo 2-D inversion scheme versus a full 2-D inversion using a realistic synthetic example shows that the pseudo 2-D inversion scheme performs as well as the full 2-D inversion, but in a much shorter time.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.