CO_2混相驱油井产能预测方法

Well productivity prediction research for CO_2 miscible flooding

为预测CO2混相驱油井产能,基于混相驱机理,建立一注一采和五点法井网布井方式下CO2混相驱油井产能预测模型.模拟结果表明:在油层和流体相同条件下,一注一采和反五点井网布井方式下CO2混相驱相对于水驱油井产能有明显提高,油井产能随混相区向采油井的不断推移而增大,CO2与原油混相区突破后,存在某一井底流压,使油井产能达到最大,随着井底流压降低,产能减小;随段塞长度增大,采油指数与累计产油量由线性关系向乘方关系转化;随累计产油量增大,采油指数和段塞长度呈类似规律变化.CO2超临界区增大对油井产能的贡献比CO2溶于原油起到作用更明显.该研究结果为配产及油井举升工艺设计提供参考.

In order to predict well productivity of CO2 miscible flooding,based on the mechanism and characteristics of miscible flooding,this paper has established one-dimensional model and two-dimensional model of well productivity prediction of CO2 miscible flooding.Simulation results show that CO2 miscible flooding is an effective way to improve well productivity.Well productivity increasing with the miscible region constantly goes to the production.After the miscible region break,there is a certain bottom-hole pressure,which makes the well productivity to achieve maximum.If the bottom-hole pressure continues to reduce,the production will reduce instead.With the increase of slug length,linear relations of production index and cumulative production gradually transform to be many times the power relationship;also,with the cumulative production increases,the relationship between production index and slug length also presents the similar change characteristics.Supercritical CO 2 area increase has more prominent impact on well productivity than the influence that CO2soluble in crude oil.The results can provide reference and theoretical basis for production allocation and lifting technology design.