Study of the efficiency of nitrogen application for regulating the front of formation water movement in conditions of the manifestation of a water drive

Abstract

Using modern tools of hydrodynamic modeling, a study of the process of nitrogen injection into gas-condensate reservoirs near the initial gas-bearing contour was carried out in order to regulate the front of formation of water movement in conditions of the manifestation of a water drive. Calculations of the main technological indicators of the development of a productive reservoir were carried out for the duration of the nitrogen injection period at the level of 5, 6, 8, 10, 12, 14 months. The simulation results show that the injection of non-hydrocarbon gas ensures that the reservoir pressure in the reservoir is maintained at a higher level compared to depletion development. At the same time, it is possible to create additional hydrodynamic and filtration barriers at the initial gas-water contact, due to which there is an effective blocking of the flow of formation water into gas-saturated horizons. According to the results of the studies, it was found that in the case of the introduction of the nitrogen injection technology, significantly smaller volumes of produced water are produced in comparison with the development for depletion. The use of nitrogen as a pumping agent makes it possible to slow down the process of movement of the gas-water contact and prevent trapping of the residual reserves of natural gas. On the basis of the calculation results, the optimal value of the duration of the nitrogen injection period, beyond which the gas recovery coefficient changes insignificantly, was established. The optimum value for the duration of the injection period is 8.04 months. The predicted gas recovery factor for the optimum period of nitrogen injection is 58.11 %. When developing a gas condensate reservoir for depletion, the final gas recovery factor is 34.6 %. The results of the studies carried out indicate a high technological efficiency of nitrogen injection at the initial gas-water contact in order to regulate the process of formation water inflow into gas condensate reservoirs and increase the final gas recovery.