水力脉动波驱动微观剩余油实验与机理分析

Experimental characterization and mechanism analysis of hydraulic pulsation waves driving microscopic residual oil

为了明确水力脉动波驱动剩余油的微观机理,利用水力脉动微观可视化驱替装置开展水力脉动波驱动剩余油微观可视化实验。实验结果表明,对于水驱后残存的膜状、柱状、簇状、盲端4种剩余油类型,水力脉动波通过扰动油水界面,打破界面微平衡,使注入水侵入小孔道和盲孔与其中的剩余油接触,通过变形叠加效应将剩余油推动或剥离至主流通道,再由注入水携带驱出。其中,脉动频率主要影响簇状、盲端剩余油,频率为1 Hz的水力脉动波提高采收率效果最好;脉动振幅值主要影响膜状、柱状剩余油,振幅值越大,水力脉动波驱动剩余油越多;存在较低强度的续流压力和持压端压力可以促进脉动能量集中,大幅提高簇状剩余油的动用效果;温度升高会促进水力脉动波发挥其动用剩余油的作用,从而提高驱油效率。

To clarify microscopic mechanisms of residual oil displacement by hydraulic pulsation wave,microscopic visualization experiments of hydraulic pulsation wave driving residual oil were carried out by using the microscopic visualization device of pulsating water drive.For the four types of residual oil left in the reservoir after water flooding,i.e.membrane,column,cluster,and blind end residual oils,hydraulic pulsation waves broke the micro-equilibrium of the interface by disturbing the oil-water interface,so that the injected water invaded into and contacted with the remaining oil in small pores and blind holes,and the remaining oil was pushed or stripped to the mainstream channel by deformation superposition effect and then carried out by the injected water.In the displacement,the pulsation frequency mainly affected the cluster and blind end remaining oil,and the hydraulic pulsation wave with a frequency of about 1 Hz had the best effect in improving the recovery.The pulsation amplitude value mainly affected the membrane and column residual oil,and the larger the amplitude value,the more remaining oil the hydraulic pulsation wave would displace.The presence of low intensity freewheeling pressure and holding pressure end pressure promoted the concentration of pulsating energy and greatly improve the recovery of cluster residual oil.The rise in temperature made the hydraulic pulsation wave work better in displacing remaining oil,improving the efficiency of oil flooding.