FIELD: physics; geophysics.
SUBSTANCE: invention can be used for determining characteristics of fluids in a well logging device for taking fluid samples using nuclear magnetic resonance. The method involves using sampling apparatus to take samples of formation fluid in a well, where the sampling apparatus has a permanent magnet which forms an essentially uniform magnetic field in the sample chamber, and a radio-frequency antenna surrounding the sample chamber. The radio-frequency antenna is shielded from the permanent magnet so that, the oscillating radio-frequency magnetic field created by the radio frequency antenna does not interact with the permanent magnet. A set of nuclear magnetic resonance measurements of the fluid sample is taken by using a pulse sequence which includes pulse field gradient pulses for encoding information on diffusion. Each nuclear magnetic resonance measurement in the set is taken at a distinct parametre value in the pulsed field gradient pulses to obtain a distinct diffusion effect. The set of nuclear magnetic resonance measurements is processed and characteristics of the formation fluid are determined based on a distribution function.
EFFECT: taking measurements in conditions maximally close natural occurrence of fluids, as well as reliable determination characteristics of formation fluids.
12 cl, 8 dwg, 1 tbl, 1 ex
