Experimental Study On Impulse Characteristics Of Downhole Liquid Electric Pulse

When the oilfield is exploited in the middle and late stages,with the oil reservoir pressure reduced,various physical and chemical plugging phenomena will increase day by day,making the oil passage unimpeded,which make it difficult to extract crude oil and the production reduced.In order to solve the above problems,many domestic and foreign professionals have come up with many new technologies for blocking removal in recent years,which are applicable to different formations and blockage removal with different properties.This thesis proposes a new method of blockage removal using physical methods.The main principle is to use high-voltage pulse discharge technology to quickly release the energy stored in the energy storage capacitor through the discharge electrode to form a huge physical shock wave and generate cavitation.The blockages in the pores of the formation are cleared to form micro-cracks,which effectively relieves the pollution in the near-wellbore zone of the formation and achieves the purpose of increasing production and increasing injection.The mechanism of high-voltage pulse discharge is introduced firstly.Through the principle of liquid-electric pulse discharge and the principle of water shock wave,the whole high-voltage pulse discharge mechanism is theoretically analyzed.Secondly,the entire high-voltage electric pulse impact experimental systemcontaining the charging system,the trigger system and the discharge system,were discussed in detail respectively.In the end,experiments were carried out to explore different rocking mechanisms such as different charging voltages,media,electrode arrangements,and high static and shock waves.The experimental results show that the higher the charge voltage is,the larger the amplitude of the shock wave is;the oil-water mixture and hydrophobic water are more conducive to pulse discharge;the discharge effect with ball-ball electrode is better than the plate-plate electrode.With the increase of static pressure,the strength of the portal breakdown will also increase.When the other conditions are constant,the shock wave generated by the high-voltage pulse discharge will have less impact on the rock with the increase of static pressure,and the effect of making joints is worse.