REUTERS Brent futures LCOc1 were at $48.60 a barrel, down 14 cents but still some way from their 2015-low of $45.19, according to Reuters. U.S. crude futures CLc1 were trading 10 cents lower at $41.77 per barrel, not far off more than six-year lows touched earlier this week. Investors are concerned that the weak economic growth in Asian countries, the decline in demand from refineries in the U.S. and the growing volume of world oil production will lead to an even greater excess supply in the market, according to the report. Oil production in the U.S. is maintained at a 10-year high, averaging approximately 9.5 million barrels per day. At the same time, OPEC said its production rose to a three-year high this summer. Its members pumped 31.51 million barrels per day in July, for an increase of 101,000 barrels a day compared to June.