Research the migration pattern of oil-gas interface in gas cap expansion reservoir

Gas is continuously driven into the oil rim with the decrease of the oil rim pressure during the process of gas-cap expansion. In order to study the morphological changes in the process of oil-gas interfacial migration, the one-dimensional displacement device is used to analyze the oil-gas interface at different displacement angle and displacement velocity. The results show that the migration of outer boundary is faster than the inner boundary of the oil and gas interface in the process of oil-gas interfacial migration, and there are big differences in migration pattern of oil-gas interface at different displacement angle and displacement velocity. In order to quantitative character the interface morphology with different the displacement angle and displacement velocity, the new factor is used to describe the oil and gas interface morphology and the value of the factor can be calculated using the displacement angle and displacement velocity. The relationship between oil-gas interface form factor and displacement velocity is logarithmically determined for different displacement angles, which can provide guidance for the rational exploitation of gas-cap expansion energy with gas cap reservoir to achieve the aim of improving the overall development effect of gas cap reservoir