Mechanisms of Mass Exchange Between Light Oiland Petroleum Gas in Low-Permeability Reservoir Development Process

Abstract

It is shown that associated petroleum gas (APG) and the product of intrastratal transformation of air (by high-pressure air injection technology) are suitable for oil displacement from low-permeability, high-temperature light oil reservoirs. It was found that APG and air are effective gaseous agents miscible with oil, which are similar in oil-displacing properties. The minimum miscibility pressure (MMP) determination data are presented for an Upper Jurassic oil-APG system. The miscibility in the oil-APG system was achieved by the multicontact mechanism of interaction between oil and enriched gas. A new method is proposed for graphical determination of MMP as a function of gas breakthrough due to pressure, and a method for enhancing gas impact efficiency and for achieving miscibility at a pressure below the MMP, which consists in injection of a liquefied gas prefringe or a wide fraction of hydrocarbons, is validated.