Abstract
The ultimate recovery factor of primary and secondary recovery process can be up to approximately 40 % of oil in place. Technology development is required in order to improve and maximise the recovery and recover some of the oil left. Enhanced Oil Recovery (EOR) method been introduced to solve the main issues of poor recovery, and theoretically, Surfactant-Polymer (SP) flooding would be the EOR method that are able to maximise both, sweep and displacement efficiency. Application of ultrasonic waves and pulse vibrations in the reservoirs has been noticed to reduce the interfacial tension (IFT) between oil and water, resulting in reduction of capillary pressure in the pores and therefore, resulted to an improvement on oil recovery. Ultrasonic waves are longitudinal mechanical waves, which are generated by an infinitesimal compression of a medium. It is known that propagation of the sound waves depends on the elasticity, grain size and density of the rock. It is not certain how far an acoustic wave propagates into the reservoir, nor how such propagation occurs. The theory expects ultrasonic waves to be present in the reservoir because dispersion of low frequency waves within porous media forms high frequency harmonics (ultrasonic noise). The main focus of this research is to initiate the use of intermittent ultrasonic radiation in assisting SP flooding process under microscopic visualisation and how it enhances oil recovery through the reduction of residual oil saturation. This work has been designed to understand the mechanics of intermittent ultrasonic vibration in influencing additional recovery of SP flooding. This research is important to know more on how intermittent vibration influences the wave propagations inside the porous media. To achieve this, series of experiments consisting of visualisation and displacement experiments were conducted by using micro-model and macro-model, respectively. SP flooding with aid of ultrasonic waves was compared with normal SP flooding process. Distance of ultrasonic energy source from porous media, d, also was changed to monitor their influence on the process. Snapshots of oil displacement of glass micro-model were taken for visualisation purposes. Reduction of residual oil saturation for displacement process by using macro-model porous media were recorded. The outcomes justified that intermittent vibrations can produce and enhance more additional oil recovery of SP flooding compared to the continuous vibration, and the distance of ultrasonic energy source highly affects the residual oil left in the porous medium after SP flooding.
