Oil sludge is the by-product when producing oil, mixed with water, oil, and solid sediment, which is the dangerous waste but has high recycling value. With the increasingly tense supply of oil resources, many countries are doing researches in oil sludge recycling technology.

Drill cuttings are disposed of by injection into a subsurface formation by way of an annular space formed in a wellbore. The cuttings are removed from the drilling fluid, conveyed to a shearing and grinding system that converts the cuttings into a viscous slurry with the addition of water. The system comprises a receiving tank and a centrifugal pump for recirculating the mixture of cuttings and water (sewater) between the pump and the receiving tank. A discharge conduit is connected to the pump for moving the viscous slurry to an injection pump for high pressure injection into the formation.