Underground gas storage facilities are complex process systems that form an integral part of the Unified Gas Supply System of Russia. They include the storage facility (reservoir), wells, gas gathering stations, gas treatment section, compressor shop with gas pumping units, gas pipelines, gas metering units, treatment facilities and auxiliary equipment, i.e. almost all types of equipment normally operated at gas production and transport facilities.
At production facilities, gas recovery is a progressive process, whereas at underground gas storage facilities, the withdrawal process occurs tens of times faster (up to 6 months). This accelerated withdrawal has an adverse effect on maintaining therequired gas quality, as it imposes increased loads on equipment due to surge carryover of liquid phase with mechanical impurities, higher moisture content, and elevated gas flow velocities. In addition to the above-­mentioned features of underground gas storage facilities’ operation, one can also note the need for a significant pressure reduction from the reservoir to the trunk gas pipeline, which has a negative impact on the efficiency of separation of liquid phase from natural gas in the separators used at gas treatment plants.
The paper reviews gas treatment units used at underground gas storage facilities, which use absorption technology. The authors completed a comparative analysis of the influence of pressure during their operation atunderground gas storage facilities onthe daily output, the quality of the treated natural gas and the gas treatment costs.
The practical relevance of the work lies in determining the limitations and effects of operating gas treatment units of underground gas storage facilities at pressures of 7.5 MPa, as well as the benefits of this operating mode, including improved performance of gas treatment equipment, improved efficiency of gas separation and reduced consumption of chemical reagents (hydrate growth inhibitor).

UNDERGROUND GAS STORAGE FACILITY, CONTROL DEVICE, PRESSURE REDUCTION, GAS SEPARATION, ABSORPTION, HYDRATE FORMATION, METHANOL, TURBULENT FLOW

E.V. Zatolokin, PJSC Gazprom (Saint Petersburg, Russia)
A.S. Sergeev, Gazprom UGS LLC (Saint Petersburg, Russia)
E.N. Nesterenko, PJSC Gazprom, Peoples’ Friendship University of Russia named after Patrice Lumumba (Moscow, Russia)
D.A. Pakhomkin, Gazprom UGS LLC
A.N. Amiraliev, Gazprom UGS LLC