The Experimental Studies Of Air Injection In High Pour Point Oil Reservoir Of Buried Hill Fractured Of Shenyang Oilfield

For high pour point oil reservoirs of buried hill fracture in Shenyang oilfield,the formation of them features in the lithologically dense base rock,Low permeability,difficulty in the interactive flow between fractures and base rocks,besides,and significant heterogeneity of each layer.After nearly 30-year water flooding,this area is now facing with reservoir temperature drop,crack growth,seldom access to residual oil,the contradiction between controlling moisture and stabilizing formation pressure in water flooding is prominent,it is urgent to find a feasible method for improving the production capacity of the reservoir.Based on the related experiments,the physicochemical properties of high pour point oil,and the geological features of the interest region,this paper have built up a physical model of air injection in high pour point oil reservoir of buried hill fracture in Shenyang oilfield and took advantage of similarity theory to ensure operating parameters.Through the study on gas-water percolation characteristics,gas injection pressure,initial water saturation and The influences of the way the air injects on the effect of the development in this kind of reservoir,this paper have undertook a systematical research on the feasibility of exploiting this kind of reservoir by using air injecting LTO technology.The results indicate that low temperature oxidation was reacted between high pour point oil and air under formation temperature,the oxygen in the air will be consumed to produce CO2 and CO and the whole process will release heat.Paraffin wax content in high pour point oil decreases,the content of light hydrocarbon increases,due to the viscosity of oil decrease and wax precipitation point temperature increase.It can alleviate the cold damage brought by water flooding,increase flow capacity of the crude oil in the formation so as to improve its production.For air injection exploitation in buried hill fractured oil reservoir,retard gas breakthrough is the key to improve oil recovery.Simulation experimental results show that the increase of gas injection pressure can improve the low temperature oxidation reaction rate,effectively reduce the viscosity of crude oil,improve the mobility ratio and the swept volume of air in the formation;when we inject air into water flooded reservoir,due to the increase of water saturation,the filtrational resistance of gas phase in the porous medium has increased,and it is beneficial to extend the residence time of gas in formation;water alternating gas injection integrates the advantages from both gas flooding and water flooding,experimental results show that its ultimate recovery rate is higher than that under the single gas injection condition.Through the above research air injection for improving recovery ratio in high pour point oil reservoirs of buried hill fracture in Shenyang oilfield is feasible.Field practice also demonstrates that the results of this study have the value of popularization.