Normally, when there is sufficient geological and geophysical information available, the estimation of geological oil, gas and gas condensate reserves is carried out by the volumetric method based on 2D or 3D numerical modeling in special-purpose geological software. Similar deposits data from neighbouring fields may be used in case of lack of information, which is common in prospecting areas. The team has studied all the major petroleum provinces in Russia over the many years of experience in this field, as well as a number of regions abroad, including Belarus, Kazakhstan, Uzbekistan and the Middle East, so it has a solid database available for such scenarios. The projects that have been successfully delivered include numerous formation models traditionally classified as hard-to-recover reserves: Bazhenov and Vasyugan formations, Achimov and Domanic depositions.