The oil industry has been riding a wave of strong commodity prices for the second half of this decade, and investors have benefited from this surprising stability. As the economy chugs along, there are still opportunities to find value in one of the most profitable segments of the market. 

When we asked three Motley Fool contributors for their favorite oil stock today, ConocoPhillips (NYSE:COP), Royal Dutch Shell (NYSE:RDS-A), and ExxonMobil (NYSE:XOM) made the list. 

Oil wells operating at sunset.

Image source: Getty Images.

Impressive value for one so large

John Bromels (Royal Dutch Shell): Like a lot of investors, one of the first things I like to look at when comparing similar companies is the price-to-earnings ratio, more commonly known as the P/E ratio. This is a good, quick measurement of a company's value, and right now, the P/E ratio of Royal Dutch Shell is indicating that the company is undervalued.

Shell's current P/E is about 11.6, the lowest of the oil majors. Meanwhile, ExxonMobil's is the highest, at 17.6. Better yet, Shell's P/E has been creeping steadily downward since the end of the oil price slump in 2017. 

You can't just look at one single metric, though. But Shell's other valuation metrics look good as well. For example, the company's enterprise value-to-EBITDA ratio has likewise been on a downward trajectory since the end of the oil price slump, and while at 5.3 it's not quite the lowest in its peer group, it's pretty close to Total's 5.1. 

Of course, metrics can only tell part of the story. Investors should also be impressed by Shell's recent performance, including its outstanding Q1 2019. And the 5.8% dividend yield isn't too shabby either! Shell looks like an excellent value and a good buy right now. 

There are cheap oil stocks -- and then there are cheaper oil stocks

Rich Smith (ConocoPhillips): When it comes to "oil stocks," ExxonMobil may get all the press (and, yes, I'll admit I've contributed to that) -- but ConocoPhillips may be the better bargain.

Priced at less than 10 times earnings today, Conoco stock costs barely half the 17 P/E ratio of Exxon stock, and that's only the beginning of the good news for potential ConocoPhillips investors. With $6.6 billion in trailing free cash flow, Conoco backs up 91% of its reported net income with cold, hard cash profits. Compare that to Exxon, which seems to do a better job of generating cash. (It made $14.4 billion over the last 12 months.) But that $14.4 billion represents just 78% of the company's claimed net income.

As for where the two companies will go in the future, well, yes, it's true that ExxonMobil currently possesses the faster projected growth rate among analysts (14% annual growth expected over the next five years, which is better than Conoco's projected 9% growth rate). However, Conoco's 9% growth arguably does a better job of justifying Conoco's 10 P/E ratio, than Exxon's 14% growth rate does of justifying its 17 P/E.

Long story short, both stocks look cheap enough to buy -- and will look better the longer the current crisis in the Persian Gulf continues. But Conoco's greater cash production and cheaper valuation make it look -- to me -- like the safer choice for these troubled times.

Bigger is sometimes better

Travis Hoium (ExxonMobil): The oil and gas industry can be volatile with commodity prices rising and falling and different parts of the value chain extracting more or less value over time. For investors looking for a stability from an oil stock, it doesn't get much better than energy giant ExxonMobil

ExxonMobil has its hands in nearly every part of the oil industry from exploration to refining and marketing of oil based products. It isn't like the company isn't impacted by commodity prices, but its diversification brings stability even when prices fall. You can see below that there are ups and downs in results but ExxonMobil can make a profit in almost any market. 

XOM Net Income (TTM) Chart

XOM net income (TTM). Data by YCharts.

The stock's P/E ratio of 17.4 isn't a screaming steal, but the 4.7% dividend yield is what I think investors should be focusing on. This is a stock that will be paying a dividend as long as we're burning oil, and right now, there seems to be no end in sight. 

Big oil is the flavor of the day

All three of these picks are considered big oil stocks and maybe that's a coincidence or perhaps bigger is better in energy today and that's why we're seeing value in similar stocks.