Nowadays, more attention is paid to the search for oil and gas deposits of the basement reservoirs. Deep wells are being drilled onshore, offshore and in the deeper parts of the seas, methods for interpreting the well logging data of unconventional reservoirs have been developed. The search for oil and gas reservoirs in the basement rocks continuously provides progress in the processing of exploration data (seismic, gravimetric, magnetic surveys), as well as in interpreting these data, drilling deep wells in high-temperature zones providing a detailed study of the well space, for example, fractures according to the formation microimager.
According to the world statistics, the distribution of the explored reserves of oil and gas in the fields with basement reservoirs is 80% for granitoids, 11% for metamorphic rocks, 6% for igneous rocks and 3% for others. In total, more than 450 basin deposits are known with commercial reserves of oil, gas and condensate in 54 petroleum basins of the world (Gavrilov et.al., 2010). Most of the oil and gas deposits in the basement rocks belongs to the granitoid type of the reservoir such as the oilfields of Vietnam (Bach Ho, Dragon, Ruby, Bavi), oilfields of the Gulf of Suez, USA (Panhandle-Hugoton), Venezuela (La Paz) etc. The only example in Kazakhstan is the Oimasha Field.
In the framework of this article, the author analyzed the formation and methods of detection of granitoid prospects based on the study of world basement oilfields.