Introduction to Offshore Oil-based Mud Cuttings Recovery Process

Ⅰ. Relevant Laws and Regulations

“Ship Pollutant Emission Standards” (GB 3552-1983)

“Sea Water Quality Standards” (GB 3097-1997)

“Pollution Control Standards for Sewage Marine Disposal Projects” (GB 18486-2001)

“Comprehensive Sewage Discharge Standards” (GB 8978-1996)

“Environmental Air Quality Standards” (GB 3095-1996)

“Pollutant Emission Concentration Limit for Marine Oil Exploration and Development” (GB 4914-2008)

Ⅱ. Sea Area Definitions:

Level 1: Applicable to the Bohai Sea, the northern Gulf, nationally designated marine protected areas, and sea areas within 4 nautical miles of the nearest land.

Level 2: Sea areas between 4 and 12 nautical miles from the nearest land.

Level 3: Applicable to sea areas outside level 1 and level 2.

Ⅲ. Emission Requirements:

Non-aqueous drilling fluids are not allowed to be discharged into the sea.

Bohai Sea: Drilling fluids and cuttings from oil reservoirs cannot be discharged.

Ⅳ. KOSUN Offshore Oil-based Mud Cuttings Recovery Process

1. Cuttings flow out from the vibrating screen and enter the centrifuge through the discharge outlet or screw conveyor.

2. Oil-contaminated cuttings are dried in the centrifuge, and the solids fall directly into the cuttings box. The cuttings box, filled with the dried and treated cuttings, will be transported back to the land for further processing.

3. After drying, the solids content in the oil-based mud is significantly reduced, with solids content below 4%. To meet the requirements of strict recycling, it needs to be further separated in a centrifuge.

4. The oil-based mud separated from the drying machine flows by gravity into a fluid tank located below the drying machine. To prevent sediment accumulation, an agitator is installed in the fluid tank to ensure uniform solids content of the oil-based mud, ensuring the quality of centrifuge processing.

5. The oil-based mud is pumped from the bottom of the fluid tank into the centrifuge for further solid-liquid separation.

6. The oil-based mud, separated by the centrifuge, fully meets the requirements for reuse. It flows by gravity into a buffer tank placed below the centrifuge and is then pumped into the mud pit, returning to the circulation system. 

Ⅴ. Advantages of Offshore Oil-based Mud Cuttings Recovery:

1. The processing process is complex and precise, and the separated mud system can be reused.

2. Reduces the amount of transportation and lowers transportation costs and land treatment fees.

3. Reduces the use of recovery boxes, providing more space and requiring fewer lifts and transfers.

4. Almost unaffected by weather conditions.