The Chinese oil and gas major also said it will acquire a 50% stake for $631 million in an INEOS-owned venture based in east China that produces ABS plastic used for making automotive parts and pipes.

On top of a 600,000 tonne per year ABS plant now under construction, the companies plan to add two more facilities each capable of producing of 300,000 tonnes a year, incorporating INEOS' technology, Sinopec said.

Separately, the two firms will set up a joint venture with equal equity in the northern Chinese city of Tianjin to manufacture high density polyethylene.

The new joint venture will have a registered capital of about 623 million yuan, Sinopec said.

($1 = 6.7481 Chinese yuan renminbi)

(Reporting by Chen Aizhu; Editing by Kirsten Donovan)