Naslov
Method for inversion processing of transverse electromagnetic induction well logging measurements

Autori
Gupta, Pravin ; Kriegshauser, Berthold F. ; Jeričević, Željko ; Fanini, Otto N.

Broj patenta
USP #5, 854, 991

Godina
1998

Datum patenta
29.12.1998

Sažetak
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 calculated using the 2-dimensional model. The corrected two-frequency signals are then axially inverted to generate a 2-dimensional model. Using the corrected two-frequency signals in place of the acquired signals, all the previous steps are repeated until differences between the corrected two-frequency induction signals from successive repetitions (iterations) of the steps fall below a predetermined threshold. The two-dimensional model extant when process is halted becomes the final two-dimensional model.

Izvorni jezik
Engleski

Znanstvena područja
Računarstvo, Rudarstvo, nafta i geološko inženjerstvo

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