An expert system is included in a downhole processor designed to acquire
and process NMR data downhole in real time. The downhole processor
controls the acquisition of the NMR data based at least in part on
instructions transmitted downhole from a surface location and at least in
part on evaluation of downhole conditions by the expert system. The
downhole conditions include drilling operation conditions (including
motion sensors) as well as lithology and fluid content of the formation
obtained from other MWD data. The wait time, number of echos, number of
repetitions of an echo sequence, interecho time, bandwidth and shape of
the tipping and refocusing pulses may be dynamically changed. Data
processing is a combination of standard evaluation techniques. Selected
data and diagnostics are transmitted uphole. The expert system may be
implemented as a two stage neural net. The first stage does the formation
evaluation and the second stage controls the NMR pulse sequence.