A NEW METHOD TO ENHANCE VERTICAL RESOLUTION OF TIME-DECAY LOG USING FORWARD MODELING DECONVOLUTION OF TIME-DECAY SPECTRA

摘要

A method for enhancing measurement resolution is disclosed. In one embodiment, the method includes (1) obtaining multiple measurement samples at each of multiple positions along a borehole; (2) extracting reference index samples from the set of measurement samples; (3) determining a difference between each of the reference index samples and corresponding modeled index samples; and (4) updating a set of enhanced index samples based on the difference. The index samples are preferably chosen to be representative of the measurement samples obtained at each position, and accordingly, may be selected ones of the measurement samples, or alternatively, may be averages of the measurement samples. The aforementioned modeled index samples may be found from application of a predetermined tool response to the enhanced index samples, which in turn, may be found by iteration. Once the difference has been reduced below some threshold, the relationship between the enhanced index samples and the reference index samples may be used to calculate a deconvolution filter for all of the original measurement samples from the borehole. When applied to the original measurement samples, the deconvolution filter produces measurement samples having an enhanced resolution.