稠油与非凝析气体系高温高压PVT特性研究

发布时间：2018-05-12 19:26

本文选题：稠油 + 非凝析气　；参考：《东北石油大学》2015年硕士论文

【摘要】：稠油粘度高、流动性能差,常规方法开采效果不理想,因此,多元热流体吞吐等热采方法成为目前稠油开采的主要方法。为了改善开采效果,可以注入CO2、N2或烟道气等非凝析气体来扩大油藏加热范围、改善排水效果和采油效果。随着油藏温度、压力和流体饱和度不断变化,非凝析气与稠油体系的PVT特性也不断发生变化,而这些特性参数对研究非凝析气改善稠油开采机理、优化蒸汽与气体复合开采的注采参数,以及油藏数值模拟过程中的PVT拟合都非常重要。为此,本文采用渤海油田秦皇岛33-1南油田稠油样品,通过高温高压PVT实验,测定稠油与非凝析气体系的PVT特性参数,分析温度、压力、气体类型对PVT特性的影响规律,并结合界面张力实验研究稠油与非凝析气相互作用的微观机理,同时以CO2为代表,通过体积转换的Peng-Robinson状态方程(PR EOS)与修正的α函数相结合,研究了非凝析气和稠油体系在高温高压下相态特性。最后,进行物理驱替模拟实验,通过驱油效率的分析,验证非凝析气与稠油体系的PVT高压物性规律的有效性。开展高温高压PVT物性实验并综合分析后可以知道,CO2在秦皇岛33-1南油田稠油中具有更高的溶解度,降粘效果明显,降粘率高达86%,而N2的降粘率为19.8%,烟道气为33.8%;CO2降低密度的效果也比较明显,最高降低幅度且为8.48%,比N2的2.31%高了三倍多,而烟道气为2.97%,更接近于N2;整体来说,温度对密度和体积系数的影响相对于溶解气的影响要小很多;CO2增加体积系数幅度最大为9.85%,而N2仅为2.62%,烟道气大值为3.84%,同样更接近于N2对稠油的作用效果。非凝析气与稠油体系的降粘机理主要是气泡降粘、稀释降粘、对胶体结构的破坏以及对界面张力的影响。非凝析气与稠油的界面张力受温度影响不大,主要受溶解气的的影响;CO2降低界面张力的幅度为60%~70%要明显大于N2,从而导致CO2在稠油中有很高的溶解度。非凝析气与稠油体系的相态特性研究表明将稠油看做六拟组分时既能够准确的预测饱和压力,又能够精确预测膨胀系数。
[Abstract]:The viscosity of heavy oil is high, the flow performance is poor, and the recovery effect of conventional method is not ideal. Therefore, multicomponent thermal fluid huff and puff are the main methods of heavy oil recovery at present. In order to improve the recovery efficiency, the non-condensate gas such as CO _ 2N _ 2 or flue gas can be injected to expand the heating range of the reservoir and improve the drainage efficiency and oil production efficiency. With the change of reservoir temperature, pressure and fluid saturation, the PVT characteristics of non-condensate gas and heavy oil system change continuously, and these parameters can improve the recovery mechanism of heavy oil by studying non-condensate gas. It is very important to optimize the injection-production parameters of steam and gas complex production and the PVT fitting in reservoir numerical simulation. In this paper, the heavy oil samples of Qinhuangdao 33-1 South Oilfield in Bohai Oilfield are used to determine the PVT characteristic parameters of heavy oil and non-condensate gas system by high-temperature and high-pressure PVT experiment, and the influence of temperature, pressure and gas type on PVT characteristics is analyzed. The microscopic mechanism of the interaction between heavy oil and non-condensate gas is studied by the interfacial tension experiment. CO2 is taken as the representative, and the modified 伪 function is combined with the Peng-Robinson equation of state for volume conversion. The phase behavior of non condensate gas and heavy oil system under high temperature and high pressure was studied. Finally, physical displacement simulation experiments were carried out to verify the effectiveness of the PVT high pressure physical properties of non-condensate gas and heavy oil systems through the analysis of oil displacement efficiency. Through the physical property experiment of high temperature and high pressure PVT and comprehensive analysis, we can know that CO 2 has higher solubility in heavy oil of Qinhuangdao 33-1 oil field, and the viscosity reduction effect is obvious. The viscosity reduction rate is as high as 860.The viscosity reduction rate of N2 is 19.8. the effect of reducing density of flue gas by 33.8and CO2 is also obvious, the maximum reduction is 8.48. it is more than three times higher than 2.31% of N2, while the flue gas is 2.97. it is closer to N2; on the whole, The effect of temperature on density and volume coefficient is much smaller than that on dissolved gas. The maximum increase range of volume coefficient of CO2 is 9.85, while that of N2 is only 2.62, and that of flue gas is 3.84, which is also closer to the effect of N2 on heavy oil. The viscosity reduction mechanism of non-condensate gas and heavy oil system is mainly bubble viscosity reduction, dilution viscosity reduction, the destruction of colloid structure and the influence of interfacial tension. The interfacial tension of non-condensate gas and heavy oil is not affected by temperature, but the decrease of interfacial tension of CO _ 2 is more than that of N _ 2 by 70%, which leads to the high solubility of CO2 in heavy oil. The study on phase behavior of non-condensate gas and heavy oil system shows that heavy oil can predict both saturation pressure and expansion coefficient when it is considered as a six-component.
【学位授予单位】：东北石油大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TE345

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