Nitrogen Flooding versus Methane Flooding in Volatile Oil Reservoirs

摘要

The main objective of the study is to find out the differences in displacement characteristics between nitrogen flooding and methane flooding in a typical North Sea volatile oil reservoir. To do this the authors addressed the following topics: description of the phase behavior and physical properties of volatile oil/injection gas systems; determination of the minimum miscibility pressure of volatile oil for methane flooding and for nitrogen flooding; flooding experiments in a slim tube apparatus; and numerical simulation of slim tube experiments. As a prototype oil the authors used a simple, synthetic three-component oil with similar characteristics to a North Sea volatile oil. Although this is a drastic simplification, the advantage is that the system is well defined. This makes it easier to interpret the complex phenomena that occur during the flooding process.