Second‑generation Haiheng Drilling‑fluid Cooling Technology Achieves On‑site Breakthrough for CNOOC

According to China National Offshore Oil Corporation, the second‑generation Haiheng surface cooling technology for high‑temperature drilling fluid, independently developed by China Oilfield Services, has completed successful field deployment. Its cooling efficiency is more than 60 per cent higher compared with conventional cooling facilities.

As offshore oil‑and‑gas exploration in China extends into deeper waters and deeper underground formations, drilling operations are facing harsher operating conditions. Rising well bottom temperatures leave returning drilling fluid at persistently high temperatures once it reaches the surface. Excess heat accelerates mechanical wear, triggers equipment faults and causes failure of rubber sealing components. 

It also degrades drilling‑fluid properties and worsens working‑site conditions, creating risks for operational safety. Traditional cooling gear can only deliver a temperature drop ranging between 10 and 15 degrees Celsius. 

These older units struggle to offer sufficient cooling service for deep high‑temperature wells, while suffering from frequent pipeline blockages and heavy maintenance workloads.

The research team focused on heat‑transfer mechanisms of drilling fluid and adopted a technical pathway featuring high‑efficiency heat exchange, intelligent control and modular integration. 

This work delivered an offshore on‑site cooling facility for drilling fluid. A prototype system was put through testing at one well within the Bohai Oilfield in February this year. It ran steadily under a high flow‑rate condition of 190 cubic metres per hour, with measured pressure drop closely matching earlier simulation outcomes. 

Further fine‑tuning of processes and parameters based on findings from the Bohai trial brought about the final second‑generation Haiheng solution.

Full‑chain domestic development covers equipment design, process optimisation and practical field roll‑out. This technology strengthens operational efficiency as well as safety safeguards for developing deep‑water and deep‑formation hydrocarbon reserves offshore. It provides a replicable, deployable home‑grown technical solution targeted at high‑temperature drilling‑fluid cooling operations.