Geological grounds of perspective zones for the accumulation of behind-pipe gas reserves (East-Novoselovskyi Oil-Gas Condensate Field, Dnieper-Donets Depression)

Abstract

The practical experience of long-term operation of hydrocarbon deposits confirms the presence of geomechanical processes and their significant impact on the state of the gas-saturated massif of rocks. In fields that are being operated for a long time, the prospects for industrial hydrocarbon accumulation can be associated with secondary gas traps of non-traditional type, in particular, technogenic ones, which are formed in low-pore reservoirs. A detailed analysis of the geological conditions of the East-Novoselovskyi field was carried out. They contribute to the formation of additional gas resources (“behind-pipe reserves” category), as well as the establishment of geological-industrial indices of the perspectivity for the formation of technogenic deposits was carried out. The purpose of the work is geological justification and finding perspective zones for the accumulation of behind-pipe reserves through the formation of technogenic deposits under the impact of a geomechanical factor, using the example of the East-Novoselovskyi oil-gas condensate field. For the geological conditions of the East-Novoselovskiy Oil-Gas Condensate Field, producing the additional gas reserves should be expected from technogenic deposits that are located above the industrial horizons that are being developed and formed in low-porous reservoirs under the action of a geomechanical factor, as a result of their decompaction after gas extraction from an industrial reservoir as a result of its compression. In accordance with the conducted research, the most perspective section, from the standpoint of the formation of a technogenic deposit and the accumulation of behind-pipe reserves, within the East-Novoselovskyi Oil-Gas Condensate Field there is the strata identified in the area of wells No. 16, 18, 60, in the section interval at a distance of 92.4 m up from the roof of the horizon (B-3b), which is located from a depth of 2141 m to the roof of the horizon B-3a, at a depth of 2 233 m. It is worthwhile to further carry out appropriate geophysical work for conducting the technological work for the development of technogenic deposits in perspective zones behind the casing column in operated wells. The account of the geomechanical factor opens up the perspective of producing the additional industrial gas influx at the late stages of the development of gas and gas-condensate fields, by predicting the geological conditions for the formation of the improved secondary filtration-capacitive properties favorable to form technogenic gas deposits.