Elastic wave stimulation of oil reservoirs: Promising EOR technology?

Roughly 60% of oil resources in the world remains unproduced, partially due to limitations in existing enhanced recovery methods. This translates to approximately half a billion tons of oil left behind annually. Anecdotal production data, as well as historic field and laboratory experiments, have shown that low-amplitude seismic waves in the frequency range of roughly 1–500 Hz can enhance oil mobility and total recovery in mature reservoirs. It is estimated that, to date, various types of seismic and acoustic oilfield stimulation activities have produced an additional 11 million tons of oil in the Former Soviet Union alone. Unfortunately, field tests with different seismic sources have often yielded mixed or inconclusive results. In some cases seismic stimulation increased production rates by 50% or more, but in other cases production was unchanged or actually declined. So far, laboratory and field experiments have not been sufficiently comprehensive to define the physical conditions under which stress-wave stimulation is most effective. An exhaustive review of observations and research on this subject from the 1950s up through 1992 was published by Beresnev and Johnson (1994). The paper summarizes the important early research, including a large body of work published only in Russian.