Development Methods And Injection And Production Parameters Design For Heavy Oil Reservoir

Because heavy oil has the characteristics of high viscosity and high content of heavy components,thermal recovery is one of the most important development methods.How to effectively apply different thermal recovery methods to efficiently develop heavy oil resources is of a significant issue.At present,the description of the seepage characteristics of the cold zones and hot zones during the process of cyclic steam stimulation(CSS)is not yet comprehensive,and the research on prediction of its converting development methods and timing is not adequate.Therefore,this paper utilizes the reservoir engineering methods,combined with the heat and mass transfer equation,and uses the physical simulation and numerical simulation method to further describe the mechanism of thermal recovery of heavy oil and carry out in-depth study in terms of thermal recovery parameters.A semi-analytical model of vertical well CSS is proposed,based on the latent heat and sensible heat characteristics of steam and the non-Newtonian characteristics of heavy oil under low temperature condition.The model combines the seepage characteristics of heavy oil under low temperature and high temperature conditions,and reveals the characteristics of differentiated seepage characteristics of heavy oil in different temperature zones.The parameters of CSS are analyzed and optimized based on the model and the effective thermal utilization parameters.Considering the weight algorithm between isothermal flow and non-isothermal flow,based on the theory of the vertical well CSS model,a semi-analytical model of horizontal well CSS is established.A non-isothermal seepage equation and the isothermal seepage equation weighting algorithm in the production stage is proposed considering the characteristics of non-Newtonian fluid under the latent heat of steam which reveals the seepage characteristics due to the temperature variation during the production stage.Based on this model and the effective thermal utilization parameters,the parameters of steam injection and production in the process of CSS in the horizontal wells of heavy oil reservoirs are analyzed and optimized.On the basis of the "four fields" distribution in the process of steam flooding,the different steam stages are re-divided,revealing the mechanism and division criteria of each stage.The time of each stage is studied by the self-designed three-dimensional steam flooding physical simulation experiment,and then the mechanisms of heat and mass transfer are proposed.Based on the characteristics of stage recovery and heat utilization,the numerical simulation method is applied to analyze and optimize the parameters of injection and production in different stages of steam flooding to achieve the feasibility of both technology and economy.The displacement law of steam-air compound flooding is studied and the volume ratio of steam-air compound flooding is optimized upon the reservoir characteristics during the late period of steam channeling.Based on the reservoir engineering methods,the converting time and converting development methods after steamflooding are established by analyzing the declining curve of oil production and injection and production characteristics curve.Then water alternating steam process and interval steam injection are used to analyze the feasibility under different scale models.With this analysis,the injection parameters of each method are optimized.On the basis of actual block model,the converting time and development methods are shown to be correct with the using of reservoir numerical simulation.The research results of this paper have further improved the theory of cyclic steam stimulation and steamflooding.A novel CSS semi-analytical model,a new method of steamflooding stage division and optimization method of injection and development,which provides a theoretical basis for improving the development of heavy oil.