Iran has scored a success with the belated signing of its second, post-sanctions upstream deal with foreign firms. But the continued focus on developing Iran’s heavier reserves is pressuring pricing for its Iran Heavy grade.

Iran has finally secured a second contract with an IOC after signing up Total and CNPC to South Pars Phase 11 in June 2017. Russian state firm Zarubezhneft signed a contract to develop two oil fields – 30,000 b/d West Paydar and 6,000 b/d Aban – and...