Vertical 1-D inversion with thin layers of equal thickness
US6591194B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | Feb 27, 2001 |
| Grant date | Jul 8, 2003 |
| Priority date | — |
| Expiry date | May 25, 2021 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01V3/28
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
Measurements made by a multicomponent logging tool in a borehole are inverted to obtain horizontal and vertical resistivities of a formation traversed by the borehole. The model includes layers of equal thickness, each layer having a horizontal resistivity and a vertical resistivity. For a vertical borehole, the inversion is done by first iteratively obtaining the horizontal resistivities of the layer using the Hzz component of the data wherein in successive steps of the iteration, the horizontal resistivity for each layer is multiplied by a ratio of a model Hzz output to the measured Hzz. The vertical resistivity model is set equal to the derived horizontal resistivities and the iterative process is repeated using the ratio of the model Hxx output to the measured Hxx. A similar process is used for boreholes with a known inclination. For such an inclined borehole, the two horizontal components Hxx and Hyy are summed to give a horizontal measurement Hxxyy that is independent of tool rotation. The first step uses a ratio of the model Hzz output to the measured Hzz data to obtain an apparent resistivity, and, in the second step, the ratio of the model Hxxyy output and the measured Hxy…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.