The dramatic drop in global oil prices is causing havoc in the local energy sector, where falls are leading a more than $50 billion decline in the ASX's value over the past two days. Here are some numbers on the scope of the carnage among oil and gas stocks: Australia's energy sector has suffered its biggest two-day loss since before the global financial crisis, wiping $12.3 billion from the sector's market capitalisation , following OPEC's refusal to cut oil output.