EOR Miscible Gas Project in Oil-Gas Condensate Field

Abstract

The development of oil rims is usually accompanied by the production of a significant amount of associated gas. It is often a positive monetization through sale or generation of electricity, due to the remoteness of oil fields and/or consumers. This work provides experience in carrying out a technological assessment of the implementation of the miscible displacement in the oil rims by rich gas, with the simultaneous injection of dry gas in the gas cap for one multizone oil field of Western Siberia. The oil rims in the field are presented by the rims of the edge and the underlying type. The producing gas in the field is reasonably dry, with about 10% of the molar C2-C4 concentration, which prevents miscibility of gas and oil in the reservoir. In the comprehensive preparation of gas, there is a technology for the allocation of the intermediate group of C2-C4 and C1 methane, which allows the further gas to be obtained by another gas composition that satisfies the pressures and temperatures conditions of the reservoir. The base field development plan of oil rims includes the gas return to the gas cap of the reservoir of the total amount of gas produced. This development strategy to increase the level of oil production is achieved only at the expense of maintaining the reservoir pressure. More oil can be obtained through the organization of miscible displacement by rims, by increasing the proportion of mobile oil in the reservoir (reduction of residual oil saturation) and reduce oil viscosity. Increased detail calculations of phase and component behavior in the reservoir when changing pressure and component concentration fields was achieved by performing compositional simulation, the major task of which is to correct the forecast performance for oil and gas with optimization and selection of an effective strategy for gas cycling-process in the field. The article describes the basic steps to build and configure compositional model, assess the effectiveness of implementation miscible displacement and its infrastructure constraints based optimization, as well as the results of the comparison of accounts with similar projects worldwide. Based on the performed calculations identified potential to increase oil recovery and improve the effectiveness of field development.