Enhanced oil recovery

The principal enhanced recovery technique is waterflooding, because water generally is inexpensive to obtain and inject into the reservoir and it works. With the shortage of conventional oil in Canada there is greater emphasis being placed on other recovery schemes in addition to or in place of waterflooding. Tertiary recovery is applicable to many of the existing projects and engineers must recognize those fields that are candidates for tertiary recovery applications. The application of tertiary recovery techniques to a specific reservoir requires consideration of all methods developed to select the one most suitable. A thorough understanding of waterflooding and the factors that affect recovery is necessary before a tertiary process is considered. Factors that affect oil recovery under waterflooding are areal and vertical sweep efficiency, contact factor and displacement efficiency.