Oil contaminants of the hydraulic system in the gas drilling process were analyzed and a dynamic equilibrium equation of pollutants and pollutant control equations were established.According to pollution control equation,hydraulic system filter device optimization measures were proposed to further improve the design and preferred filter programs,and the main design parameters of the new back oil filter were determined.By builting a downstream particle concentration equation of the back oil filter pollutants,and calculating downstream particle concentration of pollutants to the back oil filter and non-return oil filter of the hydraulic system,it was shownd that when installing a new oil return filter,the filter of speed obviously improved,and after a certain time,the downstream particle concentration of pollutants decreased significantly.
