CO2驱油实验研究

为研究CO2驱油机理，并为制定开发方案提供基础数据，严格按照规定取样，按拟合泡点压力的配样原则配样，通过室内高压相态实验、CO2减黏效果评价实验和细管驱油实验，测定CO2-原油多组分体系的相行为，评价压力-体积关系和CO2减黏效果，认识CO2驱的机理和规律。细管驱油实验结果表明，通过采收率随驱替压力曲线的变化规律来确定混相条件最为准确，本次实验油样(胜利油田油样)最小混相压力为26MPa。对比总结国内外大量相关资料，认为对于特定油田的不同油样，相对饱和压力、归一化体积系数、膨胀系数、CO2溶解度和相对黏度等参数与CO2注入浓度的关系曲线是一定的，可以用回归的曲线进行有关预测。图4表1参13

Laboratory investigation of CO2 flooding

In order to investigate the mechanism of CO_(2) flooding and provide project data, the phase behavior, viscosity reduction and slim tubule tests were taken to measure the PVT phase behavior of reservoir fluid-CO_(2) mixture, estimate the viscosity reduction effect of CO_(2) and disclose the mechanism of CO_(2) flooding. A method to get eligible reservoir fluid samples is proposed as mixing oil and gas samples to reach the bubble point pressure. Slim tubule tests indicate that it was more appropriate to determine the minimum miscibility pressure through the curve change of oil recovery with flooding pressure. The minimum miscibility pressure of the test, using the oil and gas samples of Shengli Oilfield, was 26 MPa. The tests and literatures show that for a certain reservoir, through a slight manipulation of the measured PVT properties including bubble point pressure, volume factor, swelling factor, solubility of CO_(2) and viscosity, it is possible to obtain single property curves, which can be used to estimated the PVT behavior for any fluid-CO_(2) mixture of this reservoir.