The Bad Guys and the Good Guys in Petroleum Microbiology

There is more diversity among microorganisms such as bacteria than there is in the range of life from artichokes to zebras. Bacteria have successfully colonized virtually e very environment on earth because they can rapidly adapt to changing conditions, and use a large and varied number of nutrients to generate energy. How e ve r, until relat ively recently, the environments of many petroleum reservoirs were considered too hostile for bacterial growth due to low ava i lability of wa t e r, and high tempera t u r e s , pressures and salinities (a b ove) .1 Despite pioneering work during the 1930s and 40s in the USA by Claude Zobell, d e m o n s t rating a rich population of bacteria in water produced from shallow hy d r o c a rbon reservoirs, the possibility of bacteria existing in larger, deep reservoirs was largely ignored. The start of North Sea production in the 1960s led to the realization that bacteria could produce hydrogen sulfide [H2S] as a waste product and cause reservoir souring. The Bad Guys and the Good Guys in Petroleum Micro b i o l o g y