HEL, NYSEHEL) expects oil production to fall in the second quarter due to scheduled maintenance and the sale of its onshore oil and gas joint venture in Nigeria. Ahead of its second quarter results on July 31, the FTSE 100 oil giant said upstream production is likely to drop to between 1.66 million and 1.76 million barrels of oil equivalent per day, down from 1.86 million in the first quarter. 