Enhancement of gas recovery factor from the depleted deposit of the horizon VD-13 of the Zaluzhansky gas condensate reservoir

Abstract

Most gas and gas condensate reservoirs in the fields of Precarpathians are at the final stage of hydrocarbon production. Their development is complicated by the depletion of reservoir energy, low flow rate and water flooding wells, deterioration of the formation of the bottomhole formation zone of the reservoir and significant pressures  on the well-heads. The possible directions of enhancement of final gas recovery factor of depleted gas reservoirs are given. On the example of the depleted reservoir of the horizon VD-13 Zaluzhansky gas condensate field, the possibility of increasing the final gas recovery factor of gas withdrawal through the reduction of pressure on the well-head of the wells, the processing of hollow sections of the reservoir to reduce the coefficients of filtration resistance A and B and to ensure the stable operation of low-quality watered wells is explored. According to the results of the analysis of the redevelopment, the initial gas reserves and the forecast value of the final gas recovery factor are specified by different methods. According to the results of theoretical studies, the influence on the final coefficient of gas removal on the degree of reduction of the coefficients of filtration resistance of the hollow section of the formation A and B, pressure on the wells and the least costly gas flow rate is estimated. The optimal values of the investigated defining parameters for the conditions of the deposit of the horizon VD-13 are established. The results of the performed studies indicate that due to lower coefficients of filtration resistance A and B and pressure on the wells well and to ensure the stable operation of low-level watered wells, it is possible to increase the final gas recovery of gas withdrawal of the deposit of the horizon VD-13 from the forecast value of 72.215% under the existing development system to a value of about 90 %.