Every year Germany’s Federal Institute for Geosciences and Natural Resources (BGR) publishes its annual BGR Report showcasing BGR scientists’ work on fascinating projects in the world of geosciences. All projects are driven by BGR’s mission statement – “Planet Earth represents the basis for all our lives – its resources are limited” – and underscore BGR’s commitment to protecting the planet’s biosphere while promoting the sustainable use of natural resources. This year, one energy-related project in the field of “underground biotechnology” addressing in principle the always all-important energy supply security issue is especially worth looking at.

BGR scientists led by microbiologist Dr. Martin Krüger are currently studying the “use of microorganisms in conventionally depleted reservoirs” in a ‘pilot’ reservoir project south of Beijing (China) aimed at finding out “what microbes occur in the deposit and what metabolites they secrete [, as well as] what substances improve the solubility of oil.” In Dr. Krüger’s view the method under study has “considerable potential [and] can provide additional environmentally friendly energy resources.” The entire research is based on the hypothesis that “bacteria and other microorganisms can help extract hydrocarbons from the ground” thereby helping to increase oil production by extracting the “residual oil, which is trapped in tiny pores in the rock and is therefore inaccessible,” and ultimately enhancing overall reservoir productivity. In short, these so-called MEOR (Microbially Enhanced Oil Recovery) strategies aim to exploit many useful microorganisms below ground. Prospective MEOR strategies/processes under consideration by BGR scientists are:

1. In-reservoir microbial conversion of oil or coal that is difficult to extract to methane gas resulting in increased pressure in the oil deposit. Additionally, methane is easier to extract.
2. Causing the “microbes to produce surfactants, soap-like substances, which could remove the residual oil from the rock”.
3. Stimulation of certain microbes to “form biofilms or produce some sort of thickening agent” resulting in sealing the empty areas of a deposit off. The idea is that “[i]f water is then pumped into the reservoir, it will primarily flow into the unsealed areas, flushing out more oil.”

Microbially Enhanced Oil Recovery (MEOR)

Source: BGR 

For this research, the obvious point of departure is that oil reservoirs face natural decline rates as pressure inside the reservoir tends to decrease over time leading to continually declining production. The oil industry tries to tackle this phenomenon with enhanced oil recovery (EOR) technologies in order to extract ‘additional’ oil from existing producing fields by injecting various substances such as associated natural gas, steam, or carbon dioxide (CO2) into subsurface formations to maintain pressure and coax the residual oil towards the production wells. To learn more about this process and about the three major categories of EOR found to be commercially viable to varying degrees, visit the US Department of Energy energy.gov website here.

Enhanced Oil Recovery (EOR)

Source: Department of Energy 

According to the US Department of Energy, “with much of the easy-to-produce oil already recovered from U.S. oil fields, (…) enhanced oil recovery (EOR) (…) techniques (…) offer prospects for ultimately producing 30 to 60 percent, or more, of the reservoir’s original oil in place. In contrast, currently with the primary and secondary phases only between 20 to 40 per cent of the original oil in a reservoir can be recovered.”

Now, what makes the above-described MEOR processes so intriguing?

First, the contemplated MEOR processes would mark a distinct departure from what is generally accepted as conventional wisdom. In this respect, the BGR report notes:

“Microbes are normally undesirable intruders in oil reservoirs. These single-cell organisms transform hydrocarbons into tar-like heavy fuel oil, often producing hydrogen sulphide, a toxic and corrosive gas, in the process. In pipelines and other equipment, they form biofilms that corrode the metal or block pipes.”

Second, oil producers would ideally be able to ‘productively’ utilize something which is in the reservoirs to begin with and thus make the tertiary oil recovery phase more environmentally friendly and – under certain conditions on a case-by-case basis – perhaps even cheaper. Note, in the current lower oil price environment potentially further reducing lifting costs and enhancing existing fields’ productivity by going back-to-basics appear to be prudent ideas.