EMPIRICAL STUDY OF IMMISCIBLE WATER-GAS EFFECTS AND PREDICTION OF TERTIARY METHODS FOR INCREASING OIL RECOVERY IN CARBONATE RESERVOIRS

Abstract

The relevance. The consumption of petroleum products is growing all over the world, the share of hard-to-recover reserves is increasing, so traditional technologies do not allow the extraction of residual oil. The priority direction in oil production is the development of modern methods of increasing oil recovery, which will be able to provide a high oil recovery coefficient at already developed, as well as new fields. Such methods are water-gas exposure, polymer flooding and oil displacement by solutions of surfactants. The interest in these technologies is due to increase in the oil recovery coefficient in conditions of high-viscosity oil and low-permeability reservoirs. The main aim: evaluation of the effectiveness of the technology using experimental studies of oil displacement by water, oil displacement by nitrogen and alternating method of water-gas exposure. Object: carbonate reservoir models of the Tournaisian object of the Volga-Ural oil and gas province. Methods: studies of the oil displacement coefficient using a high-pressure filtration unit UIK-5VG: displacement by water, displacement by nitrogen and an alternating method of water-gas exposure with a cyclicity of 0,2 pore volume. In the experiments, the reservoir initial oil saturation was correctly reproduced and the coefficients of oil displacement by water comparable to the average design values were obtained. Results. Experimental studies of oil displacement by water, oil displacement by nitrogen and the alternating method of water-gas exposure have been carried out. The prospects of the technology of immiscible alternating water-gas exposure with low-viscosity and viscous oil in the conditions of a carbonate reservoir are proved. The prediction and comparison of the effect of enhanced oil recovery during displacement by solutions of polymers and surfactants with the efficiency of immiscible alternating water-gas exposure is carried out. A method for predicting the effectiveness of immiscible water-gas exposure using conversion coefficients is proposed.

Keywords

• displacement coefficient
• immiscible water-gas effect
• enhanced oil recovery
• nitrogen flooding
• polymer flooding