Improved oil production by membranes.
Remya Nair, Kjerstin Saltveit, Evgenia Protasova, Torleiv Bilstad
Vol. 32, no. 1 (2015), s. 221-231, 
The objective of this presentation is to show connections of activities leading to improved oil recovery (IOR) when prospecting for oil and gas. Increased wettability of injected water into the reservoirs is caused by specific ions. Technical limitations for production of designer water from seawater by membrane separation are highlighted. Desirable characteristics of designer water are low NaCl concentrations and high divalent ion concentrations for improving wettability of Crude Oil, Brine and Rock (CBR). Experimental setup incorporated nanofiltration (NF) membranes for ion separation. Retentate from NF contains the main constituents of Designer Water. A property of NF is to retain divalent ions. Performance of the membranes was evaluated in terms of flux and rejection under varying feed compositions, pressures and recovery rates. The research comprised a technical-economical study for salt separation. Results were evaluated in terms of desalination efficiencies and energy requirements. A sensitivity test, spiking Na2SO4 in the feed seawater, showed a decrease in retention of Cl- with increasing SO42- concentrations. A reduced permeate flux resulted, however, with increasing Na2SO4 concentrations.