Abstract

New methods for recovering petroleum are currently the object of a substantial research and development effort in the oil producing industry. This activity has been sparked by rising exploration and drilling costs, rising crude oil demand, problems in supplying far-flung crude markets, and concern for conservation of resources.

The new methods are in their infancy. Commercial applications have been extremely few. Some of the new processes have seen field pilot testing, and most have been thoroughly tested in research laboratories. At the present time, we are able to pick out their strong points and size up some of their important limitations.

The major types of new methods that are presently under study can be classified in three categories:

(1) Improvements on waterflooding, e.g., (a) flooding with a detergent solution; (b) water-driven carbon dioxide slug.

(2) Solvent extraction, or miscible displacement processes, e.g., (a) gas-driven solvent slug; (b) enriched gas drive.

(3) Thermal methods, e.g., (a) in-situ combustion; (b) hot water or steam injection.

In addition to these, there are a number of highly speculative processes upon which very little work has yet been done.

It is clear that no single new method will be the panacea — the universally applicable process. Each new method is best applied under a rather narrow band of operating conditions.

In the selection of a process for a given reservoir, the evaluation of that reservoir's properties is extremely important. While new methods are capable of recovering substantially more oil than conventional secondary recovery processes such as waterflooding and gas repressuring, they are also inherently more expensive. To insure the optimum selection and performance, every bit of available data on the reservoir should be gathered and analyzed. A clear structural picture of the reservoir and detailed data on formation properties and on the variation of those properties throughout the reservoir is essential to the tailoring of the process to the specific reservoir. Only in this manner can the optimum process and operating conditions be selected. New methods are opening up a new and challenging area for the geologist in the field of reservoir valuation and description.