VSP and acoustic logging data as well as velocities at the core samples derived from wells located in Surgutsky, Tobolsky and Nizhnevartovsky hydrocarbon-bearing regions are analyzed. Reference beds, more precisely layer differences, are detected after division of well sections into suites and subsuites and definition of interval lithology based on a well log complex. Layer velocities of compressional and shear waves as well as ? coefficient are obtained. Velocity properties analysis has revealed that it is possible to detect beds with relatively stable acoustic properties.<br>In general, all wells are marked with appropriate increase of velocity and decrease of gamma coefficient with depth. The exception is an interval of the Bazhenovsky suite. From the depth of ~ 1500 m velocities significantly vary from one well to another. It is explained by increase of fracturing with depth and peculiarities of rock transformation at the stage of earlier catagenesis.<br>The intervals of the Lulinvorsky and Berezovsky suites are distinguished by their specific peculiarities of change in velocity of compressional and shear waves, and, first of all, of coefficient ?. Such changes are due to presence of opoks in the mineralogical content (opal (SiO2) of cristobalite- thrimidite type). Decrease of ? value for the Berezovsky suite intervals, is obviously associated with presence of gas.<br>


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