Method for inversion processing of transverse electromagnetic induction well logging measurements
US5854991A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Apr 28, 1998 |
| Grant date | Dec 29, 1998 |
| Priority date | — |
| Expiry date | Apr 28, 2018 |
Classification
- Technology area (CPC E)Fixed Constructions
- CPC primaryE21B2200/22
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A method for determining the 2-dimensional distribution of horizontal and vertical electrical conductivities of earth formations surrounding a wellbore using measurements made by a transverse electromagnetic induction well logging instrument. A model is generated of the axial distribution of the horizontal and vertical conductivities, from induction signals acquired by the instrument using two-frequency alternating current. The model is generated by calculating an initial estimate of the conductivity distribution and axially inverting the estimate with respect to the measurements made using the two-frequency alternating current. Shoulder correction is applied to measurements made by the instrument using single-frequency alternating current. An estimate of the radial distribution of the conductivities is generated from the shoulder corrected induction signals acquired using the single-frequency alternating current. A 2-dimensional model is made of the conductivity distribution from the model of axial distribution and from the estimate of radial distribution. The two-frequency induction signals are corrected for near wellbore effects using two-frequency whole space responses calculat…
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