Finally, we've got Gran Tierra Energy (AMEX: GTE), which operates in Colombia, Argentina, and Peru. The Canadian company, which is headed up by veterans of EnCana (NYSE: ECA), made an unusual entry into the public markets via a reverse merger with a bulletin-board listed, Nevada-incorporated shell company called Goldstrike. The stock was also promoted early on in a snail-mail spam campaign backed by some colorful characters. Stocks like these tend to catch my wrath in Motley Fool CAPS.

Despite the inauspicious beginnings, Gran Tierra has grown into a pretty significant operator through a series of acquisitions (particularly of former partner Solana Resources) and discoveries (i.e., Costayaco in Colombia). The company sports 5.6 million net acres of leasehold, reserves of 19.2 million BOE, and 14,000 to 16,000 barrels per day of expected production capacity for the balance of the year. That production is almost all Colombian oil.

Next year, cash-rich Gran Tierra goes "elephant hunting" in Peru, and success there (no easy feat) would bring another step change in the firm's reserve and production profile. The valuation on this stock, based on production projections for the back half of 2009, is a bit below that assigned to BPZ, using that firm's guidance for 2010. I have to say I find Gran Tierra a little more interesting here, but that's based on some very preliminary research. Both should be interesting to follow