Oil prices were under pressure as global economic worries continue and traders fret over ample supply.
It comes as the UK pound sank to a 31 year low amid Brexit worries.
The concern is that recent weak data from China, the uncertainty in the UK and therefore Europe and also the US all spells a slow-down in growth and therefore demand for the black stuff.
Oil has recently been supported by the supply gluts easing and some curtailing of production from some areas but signs of ample supply are weighing.
Brent crude futures for September delivery was down 3.8% to US$48.24 barrel, while West Texas Intermediate, was also under pressure. It lost 3.5% to stand at US$47.08.
In terms of a corporate outlook, broker VSA notes exploration has been the biggest victim of the oil rout as companies have slashed capex budgets, delayed final investment decisions and shelved plans in order to survive the downturn.
"Following a fall in 2014, a further decline in hydrocarbon discoveries was observed in 2015 as just 12Bboe of recoverable resources was discovered, the lowest amount since 1952. Furthermore, the volume of oil alone discovered in 2015 was just 2.8Bbbl. We expect this trend to continue," it said.