As slumping prices force the delay, or cancellation, of oil and gas projects, Trevor Wallace could not be busier.

The president of PetroMark Energy, a small exploration and production company, left his Houston office on a cold day recently to drive down to Galveston county to see a gas field his company has been approached about buying into. PetroMark is among the minority in the industry whose investors have not pulled back, in spite of plunging commodity prices, the lack of credit and a slowing economy.