Category: Enhanced Oil Recovery

Table 11.2 contains the screening criteria that have been compiled from the literature for the miscible, chemical, and thermal techniques. Table 11.2 Screening Criteria for Tertiary Oil Recovery Processes The miscible process requirements are characterized by a low-viscosity crude oil and a thin reservoir. A low-viscosity oil will usually contain enough of the intermediate-range components for the…

A large number of variables are associated with a given oil reservoir—for instance, pressure and temperature, crude oil type and viscosity, and the nature of the rock matrix and connate water. Because of these variables, not every type of tertiary process can be applied to every reservoir. An initial screening procedure would quickly eliminate some…

The main technical problems associated with thermal techniques are poor sweep efficiencies, loss of heat energy to unproductive zones underground, and poor injectivity of steam or air. Poor sweep efficiencies are due to the density differences between the injected fluids and the reservoir crude oils. The lighter steam or air tends to rise to the…

Early attempts at in situ combustion involved what is referred to as the forward dry combustion process. The crude oil was ignited downhole, and then a stream of air or oxygen-enriched air was injected in the well where the combustion was originated. The flame front was then propagated through the reservoir. Large portions of heat…

The steam-drive process is much like a conventional waterflood. Once a pattern arrangement is established, steam is injected into several injection wells while the oil is produced from other wells. This is different from the steam stimulation process, whereby the oil is produced from the same well into which the steam is injected. As the…

The steam-cycling, or stimulation, process was discovered by accident in the Mene Grande Tar Sands, Venezuela, in 1959. During a steam-injection trial, it was decided to relieve the pressure from the injection well by backflowing the well. When this was done, a very high oil production rate was observed. Since this discovery, many fields have…

Primary and secondary production from reservoirs containing heavy, low-gravity crude oils is usually a very small fraction of the initial oil in place. This is due to the fact that these types of oils are very thick and viscous and, as a result, do not migrate readily to producing wells. Figure 11.10 shows a typical relationship between…

The main technical problems associated with chemical processes include the following: (1) screening of chemicals to optimize the microscopic displacement efficiency, (2) contacting the oil in the reservoir, and (3) maintaining good mobility in order to lessen the effects of viscous fingering. The requirements for the screening of chemicals vary with the type of process.…

Microbial enhanced oil recovery (MEOR) flooding involves the injection of microorganisms that react with reservoir fluids to assist in the production of residual oil. The US National Institute for Petroleum and Energy Research (NIPER) maintains a database of field projects that have used microbial technology. There has been significant research conducted on MEOR, but few…

When an alkaline solution is mixed with certain crude oils, surfactant molecules are formed. When the formation of surfactant molecules occurs in situ, the interfacial tension between the brine and oil phases could be reduced. The reduction of interfacial tension causes the microscopic displacement efficiency to increase, thereby increasing oil recovery. Alkaline substances that have…