Because of differences in density and viscosity between the injected fluid and the reservoir fluid(s), the miscible process often suffers from poor mobility. Viscous fingering and gravity override frequently occur. The simultaneous injection of a miscible agent and brine may take advantage of the high microscopic displacement efficiency of the miscible process and the high… Continue reading Problems in Applying the Miscible Process

The use of inert gases, in particular CO2 and N2, as injected fluids in miscible processes, has become extremely popular. The representation of the process with CO2 or N2 on the ternary diagram is exactly the same as the high-pressure vaporizing process, with the exception that either CO2 or N2 becomes a component and methane is lumped with the intermediates.… Continue reading Inert Gas Injection Processes

Multiple-contact or dynamic miscible processes do not require the oil and displacing fluid to be miscible immediately on contact but rely on chemical exchange between the two phases for miscibility to be achieved. Figure 11.8 illustrates the high-pressure (lean-gas) vaporizing, or the dry gas miscible process. Figure 11.8 Ternary diagram illustrating the multicontact dry gas miscible process. The… Continue reading Multiple-Contact Miscible Processes

Multiple-contact or dynamic miscible processes do not require the oil and displacing fluid to be miscible immediately on contact but rely on chemical exchange between the two phases for miscibility to be achieved. Figure 11.8 illustrates the high-pressure (lean-gas) vaporizing, or the dry gas miscible process. Figure 11.8 Ternary diagram illustrating the multicontact dry gas miscible process. The… Continue reading Multiple-Contact Miscible Processes

The phase behavior of hydrocarbon systems can be described through the use of ternary diagrams such as Fig. 11.6. Crude oil phase behavior can typically be represented reasonably well by three fractions of the crude. One fraction is methane (C1). A second fraction is a mixture of ethane through hexane (C2-C6). The third fraction is the… Continue reading Single-Contact Miscible Processes

It was noted that the microscopic displacement efficiency is largely a function of interfacial forces acting between the oil, rock, and displacing fluid. If the interfacial tension between the trapped oil and displacing fluid could be lowered to 10–2 to 10–3 dynes/cm, the oil droplets could be deformed and squeeze through the pore constrictions. A miscible process… Continue reading Miscible Flooding Processes

During the early stages of a waterflood in a water-wet reservoir system, the brine exists as a film around the sand grains, and the oil fills the remaining pore space. At an intermediate time during the flood, the oil saturation has been decreased and exists partly as a continuous phase in some pore channels but… Continue reading Mobilization of Residual Oil

Tertiary oil recovery refers to the process of producing liquid hydrocarbons by methods other than the conventional use of reservoir energy (primary recovery) and secondary recovery schemes discussed in the last section. In this text, tertiary oil recovery processes will be classified into three categories: (1) miscible flooding processes, (2) chemical flooding processes, and (3)… Continue reading Tertiary Oil Recovery

Gasflooding was introduced in where the injection of an immiscible gas was discussed in retrograde gas reservoirs. Gas is frequently injected in these types of reservoirs to maintain the pressure at a level above the point at which liquid will begin to condense in the reservoir.10,11 This is done because of the value of the liquid… Continue reading Gasflooding

Equation (11.1) is an expression for the overall recovery efficiency for any fluid displacement process: where E = overall recovery efficiency Ev = volumetric displacement efficiency Ed = microscopic displacement efficiency The volumetric displacement efficiency is made up of the areal displacement efficiency, Es, and the vertical displacement efficiency, Ei. To estimate the overall recovery efficiency, values for Es, Ei, and Ed must be… Continue reading Estimation of Waterflood Recovery Efficiency