微流控平台的高温高压超临界CO_(2)驱油实验

High Temperature and High Pressure Supercritical CO_(2) Flooding Experiment Based on Microfluidic Experimental Platform

基于微流控实验平台的超临界CO_(2)驱油系统,探索了致密油藏注CO_(2)提高原油采收率效果。设计的微观刻蚀芯片最小喉道直径为30μm,控制系统压力实现不同开采压力下多孔介质中CO_(2)驱油的可视化模拟,结合图像处理从渗流特征、微观机理和剩余油分布等对驱油过程进行分析。考虑油-孔喉接触关系,将剩余油分为簇状、多孔状、角隅状、柱状和膜状5种形态,并探讨了超临界CO_(2)对原油的溶解、溶胀、抽提携带及萃取混相等提高采收率机理。当压力由5 MPa升高到20 MPa时,剩余油含量由58%降低至15%,效果较好。该实验设计展示了多孔介质中流体的流动,能够对CO_(2)和原油间的微观作用机理进行剖析,同时可分析剩余油的分布和形态,也为其他注入介质驱油实验提供参考。

A flooding system of supercritical CO_(2) based on microfluidic experimental platform is designed to explore the effect of CO_(2) injection in tight reservoirs.The minimum throat diameter of the designed micro-etching chip is 30μm,and the pressure of the oil displacement system is controlled to realize the visual simulation of CO_(2) displacement in porous media under different production pressures.Combined with image processing,the oil displacement process is analyzed from the aspects of seepage characteristics,microscopic mechanism and residual oil distribution.Considering the oil-pore-throat contact relationship,the remaining oil can be divided into five types:cluster,porous,corner,column and membrane.The mechanism of dissolution,swelling,extraction and carrying of supercritical CO_(2) to improve oil recovery is revealed.When the pressure increases from 5 MPa to 20 MPa,the remaining oil content decreases from 58%to 15%,which has a better oil displacement efficiency.The experimental design intuitively shows the flow of fluid in porous media,extracts the microscopic mechanism of interaction between CO_(2) and crude oil,and analyzes the distribution and form of remaining oil,which also provides a reference for other injection media flooding experiments.