China's first self-developed subsea Xmas tree system has successfully completed trial operation in the Bohai Sea.

China National Offshore Oil Corporation (CNOOC), which conducted the trials, said that the trials lasted 32 days and involved 98 rigorous tests.

The CNOOC announced that through the tests, the reliability, safety and functionality of the system have been fully verified.

The tree system is believed to be an important piece of equipment for offshore drilling and extraction.