ExxonMobil, Shell, BP, Chevron and Phillips 66 all reported lower third quarter earnings last week. Phillips 66, which has no upstream segment, was the worst performer as earnings fell to $535 million, compared with earnings of $1.6 billion in the third quarter of 2012. Chevron fared the best of all these, reporting earnings last Friday of $5.0 billion for the third quarter 2013, compared with $5.3 billion in the 2012 third quarter. In essentially all instances the downstream segments reported lower earnings, mainly due to lower margins on refined product sales, while upstream segments earnings were mixed compared to the third quarter in 2012

ExxonMobil last Thursday said its third-quarter earnings fell 18%, as profits at its downstream segment plunged on significantly weaker refining margins, masking growth at its exploration and production business. ExxonMobil reported net income of $7.87 billion, down from $9.57 billion, a year earlier. Revenue declined 2.4% to $112.37 billion. In the latest period, the company’s refining and marketing business reported operating earnings plunged 81% to $592 million, as weaker margins, primarily in its refining business, decreased profits by $2.4 billion. Exploration and production operating earnings rose 12% to $6.71 billion. Production increased 1.5% on an oil-equivalent basis.

Royal Dutch Shell reported earnings on a current cost of supplies basis — which strips out the impact of fluctuations of oil prices between when it is produced and when it is sold — of $4.25 billion (3.10 billion euros), compared with $6.15 billion in the same quarter a year ago. Net profit, which does not strip out those fluctuations, fell to $4.68 billion from $7.16 billion. The company said that its third quarter earnings fell due to a weaker refining market and higher exploration and production expenses. Output fell due to shutdowns of facilities for maintenance, notably in Nigeria, where Shell has suffered from attacks on pipelines. Production, meanwhile, fell by 2 percent to 2.93 million barrels per day, causing the division's earnings to fall 29 percent to $3.46 billion. Downstream earnings, which include the company's refining and chemicals businesses, fell 43 percent to $892 million. Shell's consolidated revenue was $117 billion, from $112 billion in the same period a year ago. CEO Peter Voser is stepping down at the end of the year, to be replaced by Ben van Beurden.

BP reported last Wednesday a 34 percent drop in third-quarter net profit, and said it would divest another $10 billion in assets. BP blamed a drop in refining margins for the decrease in net profit to $3.5 billion in the quarter ended September 30 from $5.28 billion in the same period a year earlier. Total production for the third quarter was 3.17 million barrels of oil equivalents a day, driven mainly by growth in production from new projects. Chief Executive Bob Dudley also said the company plans to sell off $10 billion in assets before the end of 2015, with the proceeds set to go to shareholders, such as in the form of share buybacks. BP, which has already set aside more than $42 billion for the 2010 oil spill in the Gulf of Mexico, did not elaborate on its current estimates for the costs of the Gulf spill, but said it might revisit its provisions at a later date.

Phillips 66 announced last Wednesday third-quarter earnings of $535 million, compared with earnings of $1.6 billion in the third quarter of 2012. Adjusted earnings were $1.9 billion in the same period last year. Refining reported a third-quarter loss of $2 million, compared with earnings of $1.5 billion in the third quarter of 2012. Third-quarter earnings for Marketing and Specialties were $240 million, an increase of $142 million from the same quarter last year. Third-quarter 2013 Chemicals earnings, which reflect Phillips 66's equity investment in Chevron Phillips Chemical Company (CPChem), were $262 million. During the same period last year, Chemicals generated earnings of $153 million and adjusted earnings of $275 million. The Midstream segment generated earnings of $148 million in the third quarter of 2013, compared with a loss of $72 million and adjusted earnings of $88 million in the same period last year.

Chevron fared the best of all these, reporting earnings last Friday of $5.0 billion for the third quarter 2013, compared with $5.3 billion in the 2012 third quarter. Sales and other operating revenues in the third quarter 2013 were $57 billion, compared to $56 billion in the year-ago period. U.S. downstream operations earned $249 million in the third quarter 2013 compared with earnings of $456 million a year earlier. The decrease was mainly due to lower margins on refined product sales and higher operating expenses reflecting repair and maintenance activities at company refineries. The decrease was partially offset by higher earnings from the 50 percent-owned Chevron Phillips Chemical Company LLC. International downstream operations earned $131 million in the third quarter 2013 compared with $233 million a year earlier. U.S. upstream earnings of $1.03 billion in the third quarter 2013 were down $96 million from a year earlier, as higher crude oil and natural gas realizations and increased production were more than offset by higher depreciation, exploration and operating expenses. International upstream earnings of $4.07 billion increased $49 million from the third quarter 2012.