Patent ID: 7180287

Claim:
A method of obtaining NMR spin echo signals from an earth formation comprising: (a) conveying a logging tool into a borehole in said earth formation; (b) polarizing nuclear spins in said earth formation using a magnet on said logging tool; (c) pulsing an antenna on said logging tool with a pulse sequence and producing spin echo signals, said pulse sequence including an excitation pulse and at least one refocusing pulse, said excitation pulse and said at least one refocusing pulse of the pulse sequence each having first and second associated volumes respectively where a resonance condition is satisfied, said logging tool having a motion between a time of application of said excitation pulse and a time of application of said at least one refocusing pulse; and (d) making the first volume smallr than the second volume by selecting a parameter of at least one of (A) said excitation pulse, and, (B) said at least one refocusing pulse.