The results of investigation of the phase behavior of a crude oil sample from the Kalchinsk oilfield at pressure up to 1.43 GPa in the temperature range of 140-336 K are presented. It is shown that crystallization occurs in the sample with increasing pressure (decreasing temperature) in a wide range of thermobaric parameters, after which the glass transition process is observed. Based on the experimental data, a phase diagram for the studied sample was constructed.