China’s oil and gas sector is facing “enormous challenges” in boosting reserves and expanding production after achieving record-high output last year as part of Beijing’s energy security drive, according to a report released by the National Energy Administration (NEA).Total oil and gas production reached a new high of 420 million tonnes of oil equivalent last year, with crude oil output hitting a record 216 million tonnes, which the NEA said had “considerably enhanced self-reliance”.But the...