Study On Clean Fracturing Fluid Of Coalbed Gas

Polymer flooding technology has been one of the important stimulation ways in the tertiary oil recovery.It enhances oil production in offshore platform to some extent and has been used generally in stimulation ways of some blocks of BoHai Oilfield.However,the problem of waste water produced in polymer flooding stimulation is more and more obvious during the process of enhancing oil recovery,which has been a new difficult problem in waste water treatment of offshore platform.Treatment of petroleum effluent by Elctrocoagulation Method is a new way,widely used all over the world.Its effect on the treatment of polymer contained in wastewater is efficient;however,it cannot be applied vastly on platform for the limited conditions.Hence,the wastewater treatment methodology needs to be optimized.This work studied the Elctrocoagulation Method from four aspects: power frequency choice,electrode material,electrode design,and sensitizer choice.Based on laboratory experiments and data analysis,the power consumption of ordinary direct-current main and high-frequency direct-current main were calculated.With the evaluatation of its effects,the supply power of Elctrocoagulation Method was optimized.Based on the electrode evaluating experiments that using iron net,aluminum net and carbon rod as two-dimensional electrode,iron grains and aluminum grains as three-dimensional electrode,elctrocoagulation effects of different electrode materials array configuration were evaluated to upgrade the electrode.To guarantee the efficiency of three-dimensional electrode,self-washing and steam manifold system were designed.Degraded polymer that produced by elctrocoagulation experiment by means of introducing microwave,designed microwave degrading test rig,and got a conclude that aluminum as a sensitizer have noticeable effect.Finally,optimized power supply,electrode,electrode sensitizer and microwave sensitizer built a polymer flooding wastewater preprocessing test rig.It contains elctrocoagulation system and microwave system two parts.Furthermore,elctrocoagulation system adopted high-frequency direct-current main(10V,30 kHz,duty ratio is 80%),electrode adopted aluminum-copper electrode,aluminum grains as sensitizer;microwave system adopted 300 mesh filter screen,and silicon carbide sensitizer.The suit ability of treating polymer flooding wastewater can reach to 1m3/h,polymer content reduced from(93.7~123.6)ppm to(0.8~3.2)ppm,power consumption is 2 degree per square.