With Chevron’s (CVX) underwhelming earnings report release on Friday, the world’s top three oil companies have now shown what a bad second quarter they’ve had.

Royal Dutch Shell ($RDS.A), world number three, and Exxon Mobil (XOM) , world number one, reported on Thursday, and both saw shares drop lower as lower oil prices during the recently ended period posed a significant drag on profits.

For its part, Chevron, the world’s second-largest oil company, reported that second-quarter net income was down to $5.37 billion, or $2.77 per share, compared to the previous year’s period during which the company netted $7.21 billion, or $3.66 per share. Revenue came in at $57.37 billion, compared to Q2 2012’s result of $62.61 billion. Analysts had on average expected earnings of $2.96 per share, on revenue of $56.01 billion.

Aside from lower crude prices, the exploration and production unit dragged 12 percent lower from the same time last year to $4.95 billion, and a contraction in refining margins brought downstream earnings more than 50 percent lower at $766 million.

Meanwhile, like its counterparts in big oil, production was also down from last year’s 2.62 million to 2.58 million barrels a day. The company had recently warned that production would come up short.

Still, investors had reason to be optismistic, as the company recently announced a shale oil joint venture with Argentina’s state-run YPF S.A. (YPF). Furthermore, the company was able to maintain a positive outlook, as investments in Australian liquefied natural gas projects should bear fruit over the next few years.

US refining and marketing operations dropped sharply as upstream earnings came in 18 percent lower at $1.08 billion, however, as a fire at the company’s Richmond, California facility last August contributed to a drop in crude output from 814,000 barrels per day to 114,000 barrels.

Chevron’s stock was down 1.65 percent heading towards the weekend, to $124.35. Despite the earnings miss, shares are up almost 19 percent in 2013.

[Image: Chevron's El Segundo, CA refinery, courtesy of Flickr Creative Commons]