Elastic‐wave stimulation of oil production: A review of methods and results

Abstract

Numerous observations accumulated principally during the last 40 years show that seismic waves generated from earthquakes and cultural noise may alter water and oil production. In some cases wave excitation may appreciably increase the mobility of fluids. The effect of elastic waves on the permeability of saturated rock has been confirmed in numerous laboratory experiments. Two related applications have arisen from these findings. In the first application, high-power ultrasonic waves are applied for downhole cleaning of the near-wellbore in producing formations that exhibit declining production as a result of the deposition of scales and precipitants, mud penetration, etc. In many cases, ultrasound effectively removes the barriers to oil flow into the well. The ultrasonic method is reported to be successful in 40-50 percent of the cases studied. In the case of successful treatment, the effect of improved permeability may last up to several months. Whereas this method has a very local effect, a second application is used to stimulate the reservoir as a whole. Here seismic frequency waves are applied at the earth's surface by arrays of vibroseis-type sources. This method has produced promising results; however, further testing and understanding of the mechanisms are necessary.

Experimental observation of dramatic differences in the dynamic response of Newtonian and Maxwellian fluids

“…Since the concept of dynamic permeability was proposed several years ago [1,2], it has been extensively used in the study of practical problems such as petroleum recovery [3], soil-ground water transport [4], fluids flowing in porous media [5,6], acoustic waves in porous media [7], wave propagation in foams [8], fluid circulation in biological systems [9], etc. The use of the dynamic permeability as originally proposed [1] however, is not quite correct for some of these systems since the fluid does not behave as a Newtonian fluid but shows viscoelastic features.…”

Monte Carlo Assessment of the Impact of Oscillatory and Pulsating Boundary Conditions on the Flow Through Porous Media

“…It has also been observed in some laboratory measurements and field applications that imposing harmonic signals into cores or reservoirs sometimes may induce higher fluid flow rates (Pan and Horne 2000). Further the fact that the pore pressure may undergo variations under the influence of seismic waves is well known to geotechnical engineers (Beresnev and Johnson 1994). In addition, laboratory experiments have shown that ultrasonic radiation can considerably increase the rate of flow of a liquid through a porous medium (Aarts and Ooms 1998).…”

Enhancement in the dynamic response of a viscoelastic fluid flowing through a longitudinally vibrating tube

“…Biot theoretically studied this phenomenon by considering the flow of a viscous fluid in a tube with longitudinally oscillating walls under an oscillatory pressure gradient. Apart from the fundamental interest, the investigation of the dynamics of fluid in porous media under oscillatory pressure gradient and oscillating pore walls is of prime importance for the recently emerged technology of acoustic stimulation of oil reservoirs [2]. For example, it is known that the natural pressure in an oil reservoir generally yields no more than approximately 10 percent oil recovery.…”