Abstract
Based on a laboratory study, reservoir simulation and pilot test are presented in this paper for CO2 miscible flooding in low permeability with thin interbedded reservoir. At beginning, reservoir description of Gao 89–1 is sited, which gives a full view of three-dimensional geological model of the field. Swelling test has been done to examine the variation of oil volume and viscosity with increase of the pressure. Slim tube test has also been conducted to determine the minimum miscibility pressure. It shows that it is much lower than the formation pressure, which can be implemented readily in the field. And long core flooding experiment has also been carried out to make a comparison of the displacement efficient between water flooding and CO2 miscible flooding. Composition modeling with CMG simulation software is applied to optimizing the flooding parameters and formula selection for Gao 89–1 reservoir. With further studies going on, pilot test has been carried out. And the result shows that the oil production rate is increased from 31 tons to 42 tons with five wells as experimental subjects. This paper demonstrates the application of CO2 miscible displacement technique in low permeability reservoir development and exhibits the advantages and prospects of this technique.
