Mechanism And Application Of Supercritical Cyclic Steam For Heavy Oil Reservoirs

As a form of thermal recovery,steam stimulation is widely used in the production of heavy oil reservoirs.However,for deep super-heavy oil reservoirs with deep burial,high viscosity and high formation pressure,conventional steam injection is difficult and effective development is difficult.Compared with steam stimulation,supercritical cyclic steam is more injectable and more suitable for ultra-deep heavy oil.Supercritical cyclic steam has high injection pressure and excellent thermal conductivity,which can make up for the shortage of saturated steam.For oil reservoirs with extremely high crude oil viscosity,deep burial depth,high original formation pressure,low steam absorption capacity,and difficult steam injection,supercritical cyclic steam can meet their production requirements.In order to achieve the goal of economically and efficiently using ultra-heavy oil reserves,this article takes the G21 block as the research object.Carried out the simulation of indoor flooding mechanism and the numerical simulation of the effect of the flooding effect.Comprehensive knowledge of existing mine tests,the technical boundary of supercritical steam throughput is given.Through relevant knowledge in the fields of critical thermodynamics,rheology and thermal recovery of heavy oil,Use indoor physics experiments to determine the composition,viscosity,and rheology of heavy oils.Determine that supercritical steam can convert heavy components in heavy oil to light components,thereby reducing the viscosity of heavy oil;Building a supercritical steam throughput numerical model,Using numerical simulation methods to study the influence of development factors and geological factors on the effects of supercritical steam throughput,Analysis of main control factors through orthogonal optimization experiment,Determine the order of the extreme differences among the factors affecting the distribution of remaining oil during high cycle throughput: Steam injection temperature> Steam injection pressure> Periodic steam injection volume> Permeability> Crude oil viscosity> Steam injection speed.Combined with the existing supercritical steam stimulation field tests to analyze the influence of reservoir structure,heterogeneity,injection parameters and other factors on the development effect of supercritical steam flooding.Evaluate supercritical steam flooding adaptability and optimize supercritical steam throughput parameters,determine a reasonable injection plan.