Research On Steam-assisted Gravity Drainage Production Model Based On Method Of Slices

With the increasing demand for oil and the constant development and consumption of conventional oil and gas resources,heavy oil is becoming more and more important in the energy structure.The development and heat transfer of steam chamber determine the development effect of SAGD in the process of steam-assisted gravity oil drainage.At present,there are many SAGD production prediction models,but most of them are steam chamber lateral development model,vertical development model is deficient,the applicability and accuracy of the model can not be judged.This paper will optimize and improve the steam chamber model based on laboratory and field production data,and analyze the factors affecting the output of SAGD.It is helpful for understanding the development characteristics of steam chamber and guiding SAGD production.Firstly,a two-dimensional SAGD experimental device is designed to simulate the mining process of SAGD under stratum conditions through laboratory experiments.The development law of steam chamber,the distribution law of temperature and pressure and the change of production are observed during the experiment.The effects of steam injection temperature and rate on production and steam chamber development were also studied.In this paper,Butler production model,linear production model and stratified production model are established.Based on these models,the production models of steam chamber rising stage and depletion stage are established.Finally,this paper compares and verifies the accuracy of the model by screening the production model with the experimental data,and uses the screening model to analyze the influence of reservoir thickness,permeability and crude oil viscosity on production.The results show that the shape of the steam chamber is more similar to that of the fan in the rising stage of the steam chamber,and the oil production rate increases continuously in this stage.In the transverse development stage,the shape of the steam chamber is close to a triangle,and the oil production rate reaches its maximum at this stage,and the oil production rate is basically stable.In the stage of steam chamber descending,oil production rate drops rapidly.The linear stratified production model and the production model at the rising stage and the depletion stage of the steam chamber fit well with the experimental results.Reservoir thickness,permeability and crude oil viscosity have great influence on the oil production rate of SAGD.The increase of reservoir thickness and the decrease of crude oil viscosity can effectively improve oil production rate.The permeability directly affects the oil recovery rate in the initial stage.The greater the permeability,the greater the initial oil recovery rate and the maximum oil recovery rate.The higher the vertical permeability,the faster the oil recovery rate increases,and the shorter the time for the steam chamber to reach the caprock.