Harmless Treatment Technology of Waste Oil–Based Drilling Fluids

Waste oil–based drilling fluids are hazardous wastes containing oil, heavy metals, and organic pollutants. The common treatment methods include pool storage, use of a secure landfills, heat treatment, and use of eel-roasting treatment technology. However, these methods not only waste many useful resources (because the oil is discarded rather than recovered) but also increase the pro-environment cost of oil companies. This article discusses the features of waste oil–based drilling fluids and develops a useful recycling and safe disposal technology for waste oil–based drilling fluids that not only recycles useful oil but also reuses and disposes of the rest of the mud and wastewater. A novel formula of oil recovering agent and sludge treatment processing formula of the waste oil–based drilling fluids was developed. In addition, a cost-effective way to deal with and recover waste oil–based drilling fluids was found. The rate of oil recovery is greater than 90%, and the quality of the recycled oil is very good and meets the requirements for No. 10 diesel for cars according to GB/T 19147-2003. The concentrations of oil, chemical oxygen demand (COD), and heavy metals in liquid of the processed mud are lower than the secondary standard number in GB8978-1996. The treated wastewater meets the requirements of sewage comprehensive emission.