Skoltech, a petroleum engineering firm based in Russia, has found that the expensive surfactants used in many enhanced oil recovery (EOR) operations may be counterproductive, with the company’s results indicating that brine could be just as effective.
A number of EOR techniques have been developed in recent years to economically exploit non-traditional oil resources like shale reserves. In little more than a decade, these technologies helped the US Permian Basin to become the world’s most productive oilfield, overtaking the Ghawar Field in Saudi Arabia. CEO Darren Woods of ExxonMobil, the maker of Mobil hydraulic oil and other industrial lubricants, also recently said that novel fracking techniques could double the production from current wells.
The discovery of Skoltech could help reduce costs as well. Through a numerical simulation and lab experiments, the researchers evaluated the effectiveness of injecting different fluids into reservoirs of shale oil. The researchers said:
“Our study considered 13 fluids and two were selected for tests on cylinder-shaped samples of oil-saturated rock from the Bazhenov Formation of Western Siberia. First we injected brine—water with a very high salt content—and measured an oil recovery factor of about 53%.”
They added that this was equivalent to extracting about half of a reservoir’s oil. A surfactant solution with sodium fatty acid methyl ester sulfonate was found to actually trap some of the oil in the rock, with it achieving the same 53% recovery factor as brine. This suggests that shale operators could potentially achieve the same output at a lower cost with a brine solution.
