Numerical Simulation Of Air Injection Development In Fractured High Pour-point Oil Reservoir In Jing’anpu Oil Field

Air injection development has been regarded as a very promising technology to enhance oil recovery because of the air has the characteristics of rich source and low cost.Oxygen and crude oil made the low-temperature oxidation reaction when the air is injected into reservoir.Oxygen is consumed and carbon oxide generated,which can guarantee the formation pressure and effectively control the water cut to achieve the aim of enhancing oil recovery.This thesis established the geological model with the equivalent medium method which used the effective permeability to consider the effect of the fracture on the permeability of the reservoir,and used the method of history matching to inspect and correct the geological model;Secondly,analysis the distribution of remaining oil on shen 625 block according to the oil saturation field,temperature field,pressure field getting from the late period of water flood,and put forward the further air injection flooding Suggestions;Thirdly,set up the component model according to laboratory experiment and made the high pour-point oil PVT phase matching,fit the saturation pressure,viscosity,the density at the formation condition and the experimental result of the differential liberation,then corrected the critical characteristic parameters of pseudo-component and binary interaction coefficient and cited Belgrave low-temperature oxidation dynamic model to simulate the process of low temperature oxidation;Finally,this thesis set up three phase multi-component model of Jing’anpu buried hill fractured high pour-point oil reservoir and forecasted the production and optimized the injection-production parameters.The main parameters optimization included air injection rate,the cycle of water alternating gas and gas liquid ratio.Through the comparative analysis of recovery factor and economic benefit,it got that the reasonable range of air injection rate is between 10000 and 20000 m~3/d,but the phenomenon of gas breakthrough will appear when the air injection development of 2 to 3 years.Therefore,we recommended the way of water alternating gas injection development;the result researching on the cycle of water alternating gas shows that the shorter the cycle is,the higher the recovery factor will be,in view of the actual situation,the reasonable water alternating gas period is from 180 to 360 days;Compared the different gas liquid ratio effect on the recovery factor,both on recovery efficiency and economic benefit of the block is reasonable gas liquid ratio is 2～3.