In the years leading to the subprime crisis in the middle of last year, the capital markets had been wide open for anyone raising capital, whether in the form of debt or equity. That is far from the case any more. But volumetric production payments (VPPs) - whereby an oil or natural gas producer receives advance payment for future production - offer another way for such companies to obtain capital. This is something that Oklahoma-based natural gas producer Chesapeake Energy took full advantage