An effective parameter in the miscible-CO_2 enhanced oil recovery procedure is the minimum miscibility pressure(MMP)defined as the lowest pressure that the oil in place and the injected gas into reservoir achieve misc...An effective parameter in the miscible-CO_2 enhanced oil recovery procedure is the minimum miscibility pressure(MMP)defined as the lowest pressure that the oil in place and the injected gas into reservoir achieve miscibility at a given temperature. Flue gases released from power plants can provide an available source of CO_2,which would otherwise be emitted to the atmosphere, for injection into a reservoir. However, the costs related to gas extraction from flue gases is potentially high. Hence, greater understanding the role of impurities in miscibility characteristics between CO_2 and reservoir fluids helps to establish which impurities are tolerable and which are not. In this study, we simulate the effects of the impurities nitrogen(N_2), methane(C_1), ethane(C_2) and propane(C_3) on CO_2 MMP. The simulation results reveal that,as an impurity, nitrogen increases CO_2–oil MMP more so than methane. On the other hand, increasing the propane(C_3)content can lead to a significant decrease in CO_2 MMP, whereas varying the concentrations of ethane(C_2) does not have a significant effect on the minimum miscibility pressure of reservoir crude oil and CO_2 gas. The novel relationships established are particularly valuable in circumstances where MMP experimental data are not available.展开更多
在油藏温度下,采用ADSA(axisymmetric drop shape analysis)技术测定了不同压力下CO2/原油和N2/原油体系的平衡界面张力。实验发现,原油与超临界CO2接触的初始阶段存在强烈的扩散作用,原油中的轻质组分被超临界CO2溶解抽提,并且随着压...在油藏温度下,采用ADSA(axisymmetric drop shape analysis)技术测定了不同压力下CO2/原油和N2/原油体系的平衡界面张力。实验发现,原油与超临界CO2接触的初始阶段存在强烈的扩散作用,原油中的轻质组分被超临界CO2溶解抽提,并且随着压力的增加,这种溶解抽提作用增强;原油与N2接触时,也存在相互扩散作用,但在本实验所测试的压力范围内(小于36MPa)并不明显。两种体系的平衡界面张力随着压力的升高逐渐降低,其中CO2/原油体系的平衡界面张力降低的幅度明显大于N2/原油体系;N2/原油体系的平衡界面张力随压力基本呈线性变化。在CO2/原油体系中,当压力低于17.7MPa时,平衡界面张力下降非常快;当压力大于17.7MPa时,CO2/原油体系的平衡界面张力下降较慢。展开更多
文摘An effective parameter in the miscible-CO_2 enhanced oil recovery procedure is the minimum miscibility pressure(MMP)defined as the lowest pressure that the oil in place and the injected gas into reservoir achieve miscibility at a given temperature. Flue gases released from power plants can provide an available source of CO_2,which would otherwise be emitted to the atmosphere, for injection into a reservoir. However, the costs related to gas extraction from flue gases is potentially high. Hence, greater understanding the role of impurities in miscibility characteristics between CO_2 and reservoir fluids helps to establish which impurities are tolerable and which are not. In this study, we simulate the effects of the impurities nitrogen(N_2), methane(C_1), ethane(C_2) and propane(C_3) on CO_2 MMP. The simulation results reveal that,as an impurity, nitrogen increases CO_2–oil MMP more so than methane. On the other hand, increasing the propane(C_3)content can lead to a significant decrease in CO_2 MMP, whereas varying the concentrations of ethane(C_2) does not have a significant effect on the minimum miscibility pressure of reservoir crude oil and CO_2 gas. The novel relationships established are particularly valuable in circumstances where MMP experimental data are not available.
文摘在油藏温度下,采用ADSA(axisymmetric drop shape analysis)技术测定了不同压力下CO2/原油和N2/原油体系的平衡界面张力。实验发现,原油与超临界CO2接触的初始阶段存在强烈的扩散作用,原油中的轻质组分被超临界CO2溶解抽提,并且随着压力的增加,这种溶解抽提作用增强;原油与N2接触时,也存在相互扩散作用,但在本实验所测试的压力范围内(小于36MPa)并不明显。两种体系的平衡界面张力随着压力的升高逐渐降低,其中CO2/原油体系的平衡界面张力降低的幅度明显大于N2/原油体系;N2/原油体系的平衡界面张力随压力基本呈线性变化。在CO2/原油体系中,当压力低于17.7MPa时,平衡界面张力下降非常快;当压力大于17.7MPa时,CO2/原油体系的平衡界面张力下降较慢。
