The Study And Application Of The Oil Bank's Formation Mechanisms In Fire Flooding

As one of the most significant technologies for heavy oil thermal recovery,fire flooding can highly enhance the oil recovery and have high research prospects.Oil bank is the most important zone in fire flooding and it is of great significance for the efficient development of fire flooding.It can enhance the vertical sweep efficiency by plugging high permeability layer and has a great impact on the production performance of a single well.This paper defines the concept of oil bank and find out the formation mechanism of oil bank in fire flooding by theoretical research.At the same time,this paper analysis the influencing factors in the formation of oil bank by univariate analysis method and numerical simulation analysis method.Finally,combined with field production performance,this paper conclude the significance of oil bank in field development.This paper study the formation mechanisms of oil bank by establishing a new single-dimensional positive dry-fire flooding mode and verify the flooding mode by single-dimensional combustion experiment.This flooding mode indicates that the main influencing factors in the formation of oil bank contain temperature,temperature gradient,oil saturation,oil saturation gradient and viscosity of oil.There are optimal conditions in the formation of oil bank and they can be optimized by orthogonal test.By establishing the temperature distribution model which take heat conduction as the main heat transfer method and consider the heat convection effect,the morphological characteristics of oil bank in fire flooding,by which we can estimate the shape of oil bank and make prediction for production,can be obtained.In this paper,a single-dimensional fire flooding numerical simulation,which describes the development characteristics of fire flooding,is build to illustrate the existence of oil bank and the location of other zones in the reservoir.The arrival of oil bank mining period can be predicted by production characteristics.Compared with other thermal development methods,the existence of oil bank is the most significant reason for the efficient development of fire flooding.Combining the production performace of field development with the indoor experiment,the production characteristics of oil bank in field development can be concluded.The conclusion in this paper has certain guiding significance for the dynamic prediction of field development.