Oil prices are on fire, recently hitting a three-and-a-half-year high. More upside could be on the way. However, despite this rebound, many oil stocks have been ice-cold, with several surprisingly having sold off to such an extent that they're currently trading at levels not seen in years. That makes them compelling options for your portfolio this month.

The bargain-basement oil behemoth

Oil giant ExxonMobil (NYSE:XOM) stumbled into 2018 after reporting lackluster results to end last year. Because of that, its stock endured its worst trading day since 2011 only to follow it up the very next one with a similar rout. While it's started to recover, it's still down 5% for the year even though oil has improved another 10%. As a matter of fact, Exxon is currently trading at a valuation not seen since the 1980s.

XOM Price to Tangible Book Value Chart

XOM price to tangible book value. Data by YCharts.

One result of this low valuation is that its dividend yield is now up near 4%, which we haven't seen since the '90s. These factors make this month an excellent one to consider buying this oil behemoth for the long haul.

A top-tier MLP for a value price

Magellan Midstream Partners (NYSE:MMP) is one of the best master limited partnerships (MLPs) around. The oil and refined products pipeline and storage company boasts one of the top credit ratings and financial profiles in the sector. As a result, the company's 5.6%-yielding distribution is on rock-solid ground.

That level is worth noting because it's at its highest since the financial crisis thanks to a nearly 14% sell-off in Magellan's unit price over the past year. That decline came despite solid financial results, enabling the company to keep increasing its payout. In fact, Magellan Midstream expects to raise its payout another 8% this year and at a 5% to 8% annual rate in 2019 and 2020, all while maintaining its top-tier financial metrics. With that growth now coming at a cheaper price, April looks like an excellent time to think about scooping up this outstanding income-focused stock.

Blocks spelling out Buy on a man's hand.

Image source: Getty Images.

A top-notch shale producer for a bottom of the barrel price

Devon Energy (NYSE:DVN) is one of the top oil and gas producers in the country. However, after running into some production problems earlier in the year, shares of the shale giant have tumbled nearly 15% even though oil prices are still moving higher. Consequently, Devon Energy's stock sells for one of the lowest valuations in its peer group.

That dirt-cheap price doesn't reflect Devon's ability to cash in on higher oil prices since it's on pace to produce more than $2.5 billion in free cash through 2020, and that's assuming $60 oil, which might be conservative now that crude is in the upper $60s. Devon seems to agree that its stock is just too inexpensive right now, which is why the company recently authorized a $1 billion share buyback program -- enough to retire 6% of its outstanding shares. That might be just the beginning because Devon is planning to sell as much as $5 billion in noncore assets, which when combined with its growing free cash flow, could give it a huge war chest to repurchase shares, making it an excellent oil stock to buy while it's still cheap.

Dirt-cheap dividend growth

Canadian energy infrastructure giant Enbridge (NYSE:ENB) has lost nearly a quarter of its value over the past year, and currently sells for just nine times cash flow, well below the peer group average of nearly 12 times 2018 cash flow. That sell-off also pushed its fast-growing dividend up to a 6.7% yield, which is the highest it has been since the early 1990's.

The plunge doesn't make much sense because Enbridge recently completed a needle-moving merger and has a massive backlog of expansion projects underway. These growth initiatives should enable the company to grow cash flow per share at a 10% annual pace through 2020, which positions it to raise its payout at a similar rate. That combination of a high current yield that Enbridge expects to grow at a high rate could fuel top-tier total returns for investors in the coming years as its valuation reverts closer to the peer group average.

Great bargains in the oil patch

It seems that investors have overlooked the fact that the oil market appears to be in full recovery mode. Because of that, some of the top stocks in the oil patch currently sell for ridiculously cheap valuations after surprisingly selling off amid the rebound. That's why these top oil-related stocks appear to be compelling ones to consider buying this month.