The collapse in oil prices is starting to slow growth in US output, OPEC said on Thursday, although the slowdown will not prevent an increasing global surplus in 2015 and demand for the exporter group's oil falling to its lowest in a decade.
In a monthly report, the Organisation of the Petroleum Exporting Countries (OPEC) forecast demand for the group's oil would drop to 28.78 million barrels per day (bpd) in 2015, down 140,000 bpd from its prior estimate and well over 1 million bpd less than it is currently producing.
Oil prices have fallen almost 60 percent since June, partly because OPEC in November decided against cutting output to retain market share against rival suppliers. The rout has put forecasts for the boom in US output in the spotlight.
"The steep drop in global oil prices could endanger the marginal barrel's output from unconventional sources," OPEC said in the report, written by its economists at the group's Vienna headquarters.
"As drilling subsides due to high costs and a potentially sustained low oil price, production could be expected to follow, possibly late in 2015."
At OPEC's meeting, top exporter Saudi Arabia urged fellow members to combat the growth in supply from competing sources including US shale, which needs relatively high prices to be economic and has been eroding OPEC's market share.
In the report, OPEC forecast total US oil supply will average 13.81 million bpd in 2015, up 950,000 bpd from 2014. The growth rate is slower than the 1.05 million bpd expected last month, but the United States is still by far the largest contributor to non-OPEC supply expansion.
OPEC is not the only oil forecaster to see a slowdown in US supplies. The US government said on Tuesday it expects domestic oil output in 2016 to grow by only 2.2 percent, the slowest pace in years.