MODELLING OF UNDERGROUND GAS STORAGE FACILITY OPERATION

Abstract

This paper refers to the problem of modeling of Ukrainian underground gas storage facilities (UGSF) operation modes and evaluating their states. Statement of this problem is connected with the phenomena that occur after UGSF operation and lead to reduction in the volume of the active and buffer zones. Based on the analysis of the work there were studies conducted and on the basis of their results the calculations were carried out in order to create conditions under which there will be no elements which increase or decrease the gas-saturated space of the UGSF, operated under the elastic water drive, at which the storage facility parameters will remain constant. In case the UGSF operation mode is changed, the adjustments of the indices must be done to stabilize the UGSF parameters. The solution of this problem is achieved by beginning the UGSF operation under the elastic water drive. It incorporates injection of the buffer and active gas volumes into the underground storage created in an aquifer reservoir to stabilize the processes in pores. Operation process involves gas injection at minimum pressure during the time, after which the neutral period begins and lasts as long as it is necessary according to technological and technical parameters. Then begins the period of active gas extraction at the pressures that range from the maximum pressure to the formation hydrostatic pressure, after which another neutral period starts. Its duration is determined with the help of calculations. Then, if the pressure (in a range from the design maximum to minimum one) changes, the duration of the neutral period is adjusted to maintain constant gas-saturated space. Adjustments are performed both after gas injection, and after its extraction.