Shares in Plexus Holding jumped on Thursday after the oil and gas engineering services group said it had entered a framework agreement with major Chinese group Yantai Jereh Oilfield Services.Yantai, a provider of integrated solutions of oilfield equipment and services, has agreed to move towards a formal, binding license to produce and sell Plexus' wellhead equipment into the Asian oil and gas markets.The two companies confirmed on Thursday that the agreement was subject to legally binding agreements being finalised and signed.Plexus shares were up 10.77% to 223.76p at 08:47 on Thursday.