Drilling oil-based mud cuttings refer to the solid waste generated during the exploration of oil and gas resources, including oil-contaminated cuttings, mud losses from shale shaker, cement slurry from well cementing, lost circulation materials, and bottom tank sediments. These solid wastes contain a large amount of oil and toxic organic substances, and their direct discharge can cause severe environmental pollution. They are classified as hazardous waste according to national regulations. The harmless treatment of drilling oil-based mud cuttings has become a challenge in the green development of oil and gas resources, and current treatment technologies have various limitations.

Kosun Environmental has integrated domestic and international methods and experiences in drilling waste treatment and proposed a one-stop drilling waste treatment solution to achieve the goal of zero waste discharge.

For water-based drilling cuttings, after separation and dewatering through vibrating screens, desanders, and centrifuges, the treatment method involves on-site cuttings pits solidification, burial, and sealing. Finally, the cuttings pit is covered and reclaimed.

Direct discharge or simple burial treatment of oil-based drilling cuttings can cause serious soil and groundwater pollution. The cuttings may also contain a large number of pathogens, parasites, and heavy metals such as copper, zinc, lead, chromium, and mercury, which can seriously affect human health and the ecological environment.

Characteristics of oil-based drilling cuttings: The cuttings produced during drilling generally have an oil content of 10% to 40% and a moisture content of 10% to 20%. They also contain a large number of odorous and toxic substances such as benzene, phenols, anthracene, and pyrene. The composition is complex, belonging to a multiphase system consisting of water-in-oil (O/W), oil-in-water (W/O), and a large amount of suspended solids. The viscosity is high, and the solid phase is difficult to completely settle.

The main equipment of the Kexun oilfield oil-based cuttings treatment system includes a cuttings dryer, high-speed variable frequency centrifuge, integrated transportation and storage tank, submersible slurry pump, agitator, screw conveyor, etc.

Oil-based Drilling Mud Cuttings Treatment Workflow:

The cuttings from the solids control shale shaker and mud cleaner at the wellsite are conveyed to the cuttings dryer system using a screw conveyor.

The cuttings are processed through the cuttings dryer unit, separating the liquid phase from the solid phase. The dried cuttings are sent to a cuttings collection box by the screw conveyor, while the liquid phase is collected in a mud tank. The dried cuttings can meet the discharge standards (according to the specific regulations of each country) or undergo further treatment.

The liquid phase in the mud tank is pumped by a submersible slurry pump to a high-speed variable frequency horizontal screw centrifuge for mud purification. The separated liquid phase enters another mud tank, while the centrifuge discharges the solid phase into a cuttings collection box.

The submersible slurry pump can return the clean mud from the centrifuge to the mud circulation system or transport the mud to the cuttings dryer for cleaning.

The collected solid phase can be transported to a centralized station or other designated locations, while the recovered oil-based mud can be reused for drilling operations.