Research On The Development Mode And Effect Evaluation For Heavy Oil Of G Oil Field

There are abundant heavy oil resources in our country.The heavy oil and asphalt resources on land account for more than 20%of the total oil resources.Therefore,the potential of heavy oil development is great.This paper mainly researches on the development mode and mechanism of ordinary heavy oil,and there are three development methods of steam stimulation in paper:steam huff and puff,cycling carbon dioxide and carbon dioxide assisted cycling steam.According to the theory of seepage mechanics,the equation of production is deduced,and the development scheme is optimized by numerical simulation.Through the study of this thesis,the conclusions are listed as follows:1.For researching on the optimization of the cycle production time of steam stimulation in heavy oil reservoir,the regression rate of production time in the cycling steam first increases and then decreases by the qualitative analysis and quantitative analysis to the period production time of the stimulation,which is beneficial to the development of oil field.2.For the problem of utilization rate of steam heat energy injected into reservoir with the steam overlying phenomenon,the study on the production calculation model of cycling steam is carried out.The relation between the heating radius of the top and the bottom of oil layer is determined for the phenomenon of steam overlaying.Based on the quasi steady state output formula,productivity prediction model of cycling steam is built for problem of steam overlay by introducing the equivalent radius.3.The technology development of cycling CO₂ and CO₂ assisted steam flooding has been advanced.According to the experimental data,the expansion coefficient and regression rate of the viscosity of crude oil are determined under different injection CO₂ mole fraction.The oil expansion experiment is fitted by the CMG software WINPROP module to determine the critical temperature,critical pressure and molecular weight,which provides data for the STARS module to determine the crude oil PVT.4.Using the actual data of G oilfield,the injection and production parameters are optimized by the numerical simulation software CMG.According to the actual reservoir situation,the economic evaluation of development is carried out by selected parameters,such as oil increment,oil change rate and output input ratio.For cycling steam,the optimum injection mass is 2400t/cycle;the injection intensity is 100t/m;the injection rate is 220t/d;the soaking time is 10 days;the injection dry quality is 0.8.For cycling CO₂,the optimum injection mass is 250t/cycle;the best injection rate is25t/d.For CO₂ assisted steam huff and puff,the periodic injection volume is 80t CO₂+1920t steam.By comparison,the economic benefit of CO₂ assisted cycling steam is higher than of cycling steam and cycling CO₂.