OPEC Secretary General Haitham Al Ghais joins CNBC's Dan Murphy at the group's international seminar in Vienna to discuss oil demand and the future of energy.

The trading slump may be confined to Shell, the biggest European energy company, but it could also be indicative of difficulties affecting others.

Output increases from oil producer group OPEC+ are not leading to higher inventories, showing that markets are thirsty for more oil, ministers and executives from OPEC nations and bosses of Western oil majors said on Wednesday.

OPEC has denied accreditation to five leading Western media outlets for its Vienna meeting, reviving tensions over press freedom and oil market transparency.

The Organization of Petroleum Exporting Countries (OPEC) continues to boost oil production, with more than 500,000 additional barrels per day set to hit global markets in August, in a bid to regain market share lost to other oil producers,

The increase, which the group said was a response to “a steady global economic outlook,” was higher than some analysts expected and could lead to lower oil prices.

OPEC+ jolted markets by announcing it would flood the market with more oil.

Another assignment that is much more definitive: the OPEC Seminar. The circus rolls back into Vienna as the oil producers' International Seminar takes place at the city's grand Hofburg Palace on Wednesday and Thursday. The meeting offers delegates two days of discussion and analysis on energy security and investment.

OPEC oil output rose in June, a Reuters survey found, led by Saudi Arabia after an OPEC+ agreement to raise production, although the increase was limited as Iraq pumped below target to compensate for earlier overproduction.

Sarah Emerson, President of ESAI Energy, talks about OPEC+ latest production hike, summer demand and supply. She speaks to Bloomberg's Joumanna Bercetche from the sidelines of OPEC's 9th International Seminar in Vienna.