25 September 2015, News Wires – The upstream oil and gas industry is constantly looking for new enhanced oil recovery technologies to improve oilfield production. And next year, plenty of EOR professionals will be taking a close look at how BP Plc’s new LoSal method for boosting oil production performs when it is deployed in a commercial environment for the first time.
LoSal is a low-salinity water-flooding technology that increases oil recovery compared to conventional seawater flooding. Flooding a reservoir with water helps to support reservoir pressure while also displacing oil from the reservoir and pushing it towards the well.
For offshore reservoirs it make sense to use seawater flooding as it is abundantly available. However, there is a problem with the chemistry of using high-salinity water in that this water encourages plenty of oil molecules to be compressed to the clay that exists within a reservoir. But the injection of fresh water into a reservoir can also cause problems by making clays swell and block the pores that hold the oil.
BP has found that simply reducing the salinity of the water can also have a positive effect on pore-scale displacement and, ultimately, oil recovery.
Even with low-salinity water, according to BP’s research, the “bridges” of divalent ions that bind the clay particles to the oil molecules become relaxed, which allows non-bridging monovalent ions to access and replace the divalent ions. With these bridges removed, the oil molecules are free to be swept towards the reservoir’s producing wells.