NEW YORK ( TheStreet) -- The huge spike in shares of Cobalt International Energy ( CIE) on Friday is your classic frontier oil exploration story. The Angolan offshore pre-salt region compares to the Brazilian pre-salt as one of the most hoped-for offshore oil gushers of the next century. Cobalt hit the proverbial pay dirt, but given Angola's profile as one of the best places to speculate for future production growth, the Goldman Sachs-backed wildcat company may not be alone in benefiting from positive drilling results in Angola. Cobalt's CEO Joseph Bryant, said in a release on Thursday night of the Angola results: "Cameia is an extraordinary success. The results have exceeded our pre-drill expectations and have increased our confidence in our entire West Africa Pre-salt exploration inventory. We will immediately commence our Cameia appraisal program." The Cobalt drilling results weren't a complete surprise. The stock had started running up late last year when another major player in the Angolan offshore, Scandinavian conglomerate Maersk, said it expected positive results from adjoining Angolan pre-salt blocs. Year-to-date Cobalt shares are up more than 100%. Here are four other oil companies to watch based on the evolving Angola story. When it comes to West African offshore exploration, Kosmos Energy ( KOS) often trades on similar sentiment to Cobalt. On Friday, Kosmos was up by 4% on three times its average trading volume. Year-to-date, Kosmos shares are up 20%. It's not just the true wildcat companies backed by big banks that stand to benefit from the Angolan pre-salt story -- Goldman Sachs is the biggest investor in Cobalt and Warburg Pincus is the largest shareholder in Kosmos. The European oil majors BP ( BP) and Statoil ( STO) are also major players in the Angolan offshore region. Early success in a frontier oil play may contribute to production but isn't likely to be a needle mover for an oil major based on initial positive results. However, discoveries like the one made by Cobalt can be a read for the entire basin, said Macquarie Securities analyst Jason Gammel. Statoil shares were up more than 1% on Friday, even as the energy sector sold off and crude oil dipped. The Macquarie analyst cautioned against reading too much into the Cobalt results, though.