Patent ID: 11960043
Assignee: SCHLUMBERGER TECHNOLOGY CORPORATION
Field: Measurement (Instruments)
Classification: CPC G | IPC G

Claim 0:
1. A method, comprising:
obtaining a waveform;
processing the obtained waveform to obtain at least one of a Stoneley, flexural, quadrupole and Pseudo-Rayleigh dispersion;
at least one of performing a computation and obtaining a library computation for interpolated theoretical dispersions of the Stoneley, flexural, quadrupole and Pseudo-Rayleigh dispersions;
performing an initial estimate of mud slowness using both the processing of the obtained waveform and the interpolating the theoretical dispersions;
calculating a mismatch between the processed waveform obtaining the at least one Stoneley, flexural, quadrupole and Pseudo-Rayleigh dispersion and the theoretical dispersions of the Stoneley, flexural, quadrupole and Pseudo-Rayleigh dispersions;
estimating at least one DTmud value as a vertical depth profile;
calculating a second mismatch between the theoretical dispersion and the processed waveform using the at least one estimated DTmud value;
estimating at least one parameter by minimizing the second mismatch;
using regression, calculating the at least one parameter over multiple depths;
updating values for the at least one parameter based upon the regression;
calculating a third mismatch between the theoretical and measured dispersions based upon the updated values for the at least one parameter based upon the regression; and
estimating a final value of the at least one parameter by minimizing a mismatch between the theoretical and measured dispersions.