Anyone who recommends an exploratory oil well company as a long term hold isn't all that bright. Just look at Givot Olam Oil company, IPO in 1993 was 40 NIS, stock price now after a major oil find is 5.3 NIS, a loss of 85% over 18 years for the long term holder (and that's with a major oil well discovery). That's what long term, and 12 billion shares outstanding, can do to you in an oil exploration company.
If you buy now in Zion Oil, Zion Oil's next well has to be a hit in order for you to do well. Otherwise, you are screwed (as currently all long time holders of Zion Oil are). Don't fall for this "long term" good deal krap. It's a gamble, and after they drill each well, it's either you win, or you lose. People have lost big money in Givot Olam. Ditto for Zion Oil. That's how the game is played.