When you look at the share prices of oil explorers, it’s a depressing sight. Over the past 12 months, Tullow Oil (LSE: TLW) is down 58% to 175p, Rockhopper Exploration (LSE: RKH) has lost 57% to 26.7p, and Solo Oil (LSE: SOLO) has slipped by 53% to 0.33p.

But you know what? Since December, the share prices have been steadier and the price of oil has picked up a little since mid-January. After dropping below $30 a barrel, Brent Crude is now fetching $34.

Up 50%!

In fact, since their recent bottom on 20 January, Tullow Oil shares have actually picked up 50%, Rockhopper is up 10% since its 8 January low, and Solo is up 8% since 25 January (and up 17% since 16 December). Does this signal the the start of the long-awaited recovery and a time to buy?

Tullow’s results on 10 February were pretty much as expected, even though they did include a $1.1bn operational loss and an extra $900m in debt added to the balance sheet, but the City responded calmly. Tullow does enjoy some low-cost assets, and its TEN field in Ghana should have operating costs of a mere $8 per barrel — although Tullow probably needs oil prices in excess of $40 to break even overall.

When the inevitable oil price rise happens, Tullow might look a good prospect, but its massive net debt of around $4bn makes me a bit twitchy. Even with $60 oil it would take a very long time to pay back that borrowed money, and I can’t see oil getting much above that level for quite some while.

Net cash

Rockhopper is in a very different position in that it has no debt. In fact, it has net cash on its books, expected to stand at around $70m to $80m by the end of 2016. And it has some tasty assets in the Sea Lion field in the North Falkland Basin. In a recent update, the firm reckoned it should be sitting on around 220 mmbbls of commercialised resources with a peak production of around 85,000 bbls per day, and a field life of around 20 years.

The big risk however, is that Rockhopper isn’t expecting first oil before 2020. It does have a farm-out agreement with Premier Oil that will help to hedge the risk, but the company’s valuation is total guesswork right now.

Smaller is bigger?

Moving to a tiny tiddler, with a market cap of just £15m, is Solo Oil worth a punt? Solo has some exciting potential, after it announced a further investment in the Kiliwani North Development Licence in Tanzania. For a payment of $2.16m to Aminex, Solo’s stake rises by 3.825% to 10%.

Solo is also a partner in the Horse Hill-1 Oil Discovery in the Weald Basin from which the latest flow tests look positive, with chairman Neil Ritson saying: “Early reports from the wellsite are extremely encouraging and certainly exceed our expectations for natural flow from the Kimmeridge limestones“.

Are any of these good investments right now? Well, they’re all risky in their different ways, but if we really are just past the bottom for oil prices then the timing could be close to perfect.

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Alan Oscroft owns shares in Premier Oil. The Motley Fool UK has recommended Tullow Oil. We Fools don't all hold the same opinions, but we all believe that considering a diverse range of insights makes us better investors.