Implementation of the new Environmental Protection Law has been increasingly pressuring on domestic oil companies. For better waste treatment while drilling and effective protection of ecological environment at well site, CNPC has introduced private capital to jointly develop drilling waste zero-discharge treatment equipment and process technology while drilling, and has purchased services in some oilfields to allow private enterprises for centralized treatment of drilling waste.



Zero drilling waste discharge technology process while drilling includes three units, including waste collection unit, gel breaking and destabilization unit and solid-liquid separation unit.
In waste collection unit, mud generated during drilling process is collected and passes through HGD high frequency shale shaker and automatic constant pressure jet flushing. The shale shaker eliminates large particle cuttings and waste mud after separation is collected and transported to low-level tank by screw conveyor for storage and then enters gel breaking and destabilization unit.



After entering gel breaking tank, waste mud forms into slurry suitable for solid-liquid separation after automatic dosing, destabilization, gel breaking and flocculation, then it is transported to solid-liquid separation unit.
In solid-liquid separation unit, mud cakes are generated out of pre-treated slurry after squeezing and reinforced solid-liquid separation by special patent equipment as a type of new building materials. Separated liquid is collected and after advanced treatment, it can be recycled in drilling production or used in system reinjection.