Oil rose nearly 7 percent on Friday to above $31 in its largest weekly rally in three months, as a cold front sweeping the United States and Europe as well as firmer financial markets gave traders reason to cash in on record short positions.
Crude futures were poised for their first weekly gain this year, but analysts said there had been no shift in the fundamental backdrop of supply that far exceeds demand and swelling inventories of unwanted oil and oil products.
