Oil futures finished higher for Friday’s session, adding to a gain for the month, with traders encouraged by the preliminary agreement between major oil-producers to scale back crude output. But prices still posted a modest loss of nearly 0.2% for the quarter. November West Texas Intermediate crude CLX6, +0.56% rose 41 cents, or 0.9%, to settle at $48.24 a barrel on the New York Mercantile Exchange. Prices finished last quarter at $48.33. For the month they climbed about 7.9%.