Methodology for interpretation and analysis of NMR distributions

An apparatus for evaluating an earth formation, the apparatus comprising:

• a logging tool configured to be conveyed into a borehole, the logging tool further configured to obtain nuclear magnetic resonance (NMR) signals at a plurality of depths in the borehole;
• and
• at least one processor configured to:
• (A) process the NMR signals to obtain a distribution of a relaxation time at each of the plurality of depths, each of the distributions comprising a plurality of bins,
• (B) use the plurality of relaxation time distributions to produce a plurality of NMR bin logs of relaxation time values for each of the plurality of bins,
• (C) determine a measure of similarity of a first log indicative of hydrocarbon content in the formation with each of the plurality of NMR bin logs, and
• (D) use the measure of similarity for each of the plurality of NMR bin logs to identify a subset of the NMR bin logs indicative of hydrocarbon.

A computer readable medium product having stored instructions thereon that when read by at least one processor cause the at least one processor to:

• process spin echo signals obtained at a plurality of depths in the borehole in the earth formation to estimate a distribution of a transverse relaxation time (T2) at each of the plurality of depths, each of the distributions comprising a plurality of bins,
• use the plurality of relaxation time distributions to produce a plurality of NMR bin logs of relaxation time values corresponding to each of the plurality of bins,
• determine a measure of similarity of a first log indicative of hydrocarbon content in the formation with each of the plurality of NMR bin logs, and
• use the measure of similarity for each of the plurality of NMR bin logs to identify a subset of the NMR bin logs indicative of hydrocarbon.