Chevron closed down more than 4% after substantially lowering its third-quarter numbers, expecting the third quarter to be more sour than an unspectacular second quarter. The company was hampered by hurricane Isaac, losing 19,000 barrels per day of production, as well as the Richmond refining accident, which decreased the company's refining capacity by 92,000 barrels per day.

Chevron's upstream operations should be back to full production for the fourth quarter, but its refining bottleneck is expected to continue until next year. The question now is what other E&P players are also expected to fall short of third-quarter estimates, since a number of companies sustained similar shutdowns after this year's hurricane season.