Scientific and methodological approach to prediction, exploration and prospecting of large and giant oil and gas accumulations confined to mega-reservoirs

When starting to formulate the scientific bases and methodologies to predict and explore large and giant hydrocarbon accumulations, authors in their research always advert to the fundamental works by scientist-thinker-practitioner Alexei Emilievich Kontorovich, Member of the Russian Academy of Sciences. The basic concepts of organic geochemistry, necessary for understanding and interpreting modern information on hydrocarbon-bearing formations, the background of geological-geophysical-geochemical knowledge about petroleum basins and naphthide ontogenesis in them are based on his works; they are devoted to oil source and oil producing formations, bitumens (allochthonous, autochthonous, parautochthonous), the main phase (stage) of oil and gas formation, catagenetic stages and zoning of oil and gas generation, and much more. Scale of bitumen migration makes the basis for the volumetric-genetic method for assessing predicted oil reserves, which was developed by A.E. Kontorovich for many regions in the Soviet Union, Russia and the union republics. This method is key to selection of exploration targets. These ideas and their refraction in a wealth of factual material are principal, fundamental, they are the cornerstone necessary for further development of new geological and geochemical research areas. The authors conducted an analysis and systematization of ideas about geological and geochemical factor influence on and oil and gas content formation in mega-reservoirs of sedimentary basins. There were several focus areas in this research, namely: general estimates of reservoir scale in world oil and gas basins are demonstrated based on a number of geological and geochemical characteristics; quantitative criteria for giant oil and gas deposit prospecting with involvement of geological and mathematical modeling and prediction of oil and gas accumulations in shale formations using geochemical methods