OUTBURST HAZARD OF SANDSTONES OF THE TYAGLIV FIELD OF THE SOUTH-WESTERN COAL REGION OF THE LVIV-VOLYN BASIN
We have investigated coal-bearing sandstones of the Tyagliv field of the Lviv-Volyn Basin (LVB). The complex of investigations on prediction of their outburst hazards has been conducted on the basis of geological- prospecting and geological-geophysical data. A special attention was paid to the wells that expose rocks oc- curred at a depth of over 700 m because it was proved that in the conditions of the LVB outbursts are absent at lesser depths. We have determined main petrographic indications that have an influence upon outburst hazard of sandstones (the amount of clastic and regenerative quartz, micaceous-clayed minerals, the size of clastic grains and extension and the type of contacts between the graines). On the basis of the calculated complex criterion of outburst hazard “B” it was possible to construct transverse profiles of the coal-bearing series with singling out of outburst-safe («В» < 0.4), low degree of outburst hazard (0.4 < «В» < 0.6), outburst- hazardous (0.6 < «В» < 1.0) sandstones. The Tyagliv field is the most gas producing one within the limits of the Lviv-Volyn Basin. While studying we have determined that sandstones n 1Sn, n Sn, n Sb are potentiallyoutburst-hazardous ones and at the same time they may be good collectors of accompanying gas-methane.