CO_2-泡沫体系的高温P-V特性研究

The Characteristic Research between Pressure and Volume of CO_2 Foam System

为满足吉林油田特低渗透区块CO2泡沫驱的要求,利用法国ST公司生产的高温高压全可视PVT测试仪,将室内静态实验筛选出的泡沫体系,进行高温P-V特性实验测定,以判断在地层的高温高压环境该泡沫体系是否能够稳定存在。实验结果表明:温度一定时,低压与高压时,PVT筒内形成泡沫的尺寸不同;低压时泡沫尺寸较大,且体系不稳定,停止搅拌立即析液;随着压力升高,PVT筒内形成的泡沫越来越细小,稳定性提高,停止搅拌析液速度减慢。通过实验观测发现,100℃时形成稳定泡沫的临界压力为30 MPa;同时该压力也是泡沫体系的P-V、P-ρ关系曲线的变化趋势变缓的转折点。最后研究发现,通过地面检测泡沫体系的密度可以判断地面发泡时是否已形成稳定的泡沫。

In order to meet the demand of CO2-foaming flooding for ultra-low permeability blocks in Jilin oilfield,the visual PVT cell of high temperature and high pressure which product model is 240 /1000 FV produced by the French ST company is used to study pressure-volume characteristics of the determined CO2 formula system,to judge whether or not steady foam system to exist.The experimental results showed that,temperature is certain,the foam sizes in PVT cell are different when pressure is low and high;when pressure is low,the foam sizes is big and foam is unsteady,drainage liquid begin at once after stopping stirring;with the rise of pressure,the foam size is smaller and smaller,the more steady of foam system,the speed of drainage liquid is slower;and by experimental observation.The critical pressure which can form steady foam system under 100 ℃ is 30 MPa,which is the turning point of pressure-volume,pressure-density relation curve of foam system.At last,it is found that can judge steady foam to exist or not by detecting the density of foam system on the surface for ground foaming.