System and Method for Automatic Petrophysical Logs Alignment

A system of characterizing a reservoir by automatic depth alignment of petrophysical logs, comprising:

• a processor;
• and
• a computer-readable non-transitory storage medium comprising instructions that, when executed by the processor, cause the processor to perform operations comprising:
• receiving a first correlation log and a second correlation log in a depth-domain;
• transforming, using a Fast Fourier Transform (FFT), the first correlation log in the depth-domain into a first frequency-domain log;
• transforming, using the FFT, the second correlation log in the depth-domain into a second frequency-domain log;
• determining, using the first frequency-domain log and the second frequency-domain log, a correlation curve of the first correlation log and the second correlation log;
• determining, using the correlation curve, a correlation metric of the first correlation log and the second correlation log;
• comparing the correlation metric to a first predetermined threshold;
• in response to determining the correlation metric is below the first predetermined threshold,
• determining, using the correlation curve, an alignment shift between the first correlation log and the second correlation log and a depth-corrected second correlation log by applying the alignment depth shift to the second correlation log;
• updating the correlation metric using the first correlation log and the depth-corrected second correlation log;
• comparing the correlation metric to a second predetermined threshold;
• and
• in response to determining the correlation metric is above the second predetermined threshold, outputting the depth-corrected second correlation log to a subsequent process of reservoir characterization.

A non-transitory computer-readable medium comprising instructions that are configured, when executed by a processor, to perform operations comprising:

• receiving a first correlation log and a second correlation log in a depth-domain;
• transforming, using a Fast Fourier Transform (FFT), the first correlation log in the depth-domain into a first frequency-domain log;
• transforming, using the FFT, the second correlation log in the depth-domain into a second frequency-domain log;
• determining, using the first frequency-domain log and the second frequency-domain log, a correlation curve of the first correlation log and the second correlation log;
• determining, using the correlation curve, a correlation metric of the first correlation log and the second correlation log;
• comparing the correlation metric to a first predetermined threshold;
• in response to determining the correlation metric is below the first predetermined threshold,
• determining, using the correlation curve, an alignment shift between the first correlation log and the second correlation log and a depth-corrected second correlation log by applying the alignment depth shift to the second correlation log;
• updating the correlation metric using the first correlation log and the depth-corrected second correlation log;
• comparing the correlation metric to a second predetermined threshold;
• and
• in response to determining the correlation metric is above the second predetermined threshold, outputting the depth-corrected second correlation log to a subsequent process of reservoir characterization.