不同烃类注入气体对黑油油藏相态特征影响研究

摘要

Gas injection is an important way to improve oil recovery ratio,the influence of gas injection on reservoir fluid characteristics is an important basis for compiling exploitation plan.With different types of injected gas and reservoir fluid,the influence of gas injection is different.Take domestic certain oilfield as an example,through physical simulation experiments in laboratory,the injection of associated gas and dry gas expansion laboratory tests is carried out and the influence of different types of injected gas on the phase behavior of crude oil is analyzed.The results show that with the injection of gas increasing,the crude oil＇s expansion coefficient,the bubble point pressure and gas-oil ratio increase;the crude oil viscosity and density decrease.After the comparison between the associated gas and dry gas injection experiments and the injection of the associated gas,it is discovered that the expansion coefficient of the crude oil becomes higher and the viscosity becomes lower,because the content of intermediate hydrocarbon component in associated gas hydrocarbon（6.91%） is higher than that of dry gas（1.28%）,according to the similarity phase solution theory,mass transfer occurs more easily between associated gas and crude oil,which is the best injection media for this oilfield.%以国内某油田为例,通过室内物理模拟实验,开展注伴生气和干气膨胀实验测试,分析不同类型注入气体对原油相态特征影响。研究结果表明,随着注入气量增大,原油的膨胀系数、泡点压力、气油比逐渐增大,原油粘度、密度逐渐降低。比较注伴生气和干气实验结果,发现注伴生气后原油膨胀系数较大、降低粘度效果最好,原因是伴生气中间烃含量高于干气。根据相似相溶原理,伴生气更容易与原油发生相间传质,是本油藏最佳注气开采介质。