Introducing a new mechanism for smart water effect in Low Salinity water flooding using membrane-like behavior of formation water
Paper ID : 1211-MST2015-FULL
1Alireza Bahramain *, 2Reyhaneh Mehrvar, 3Yadollah Bahramian, 4Hamide Ehtesabi, 5Aliyar Javadi, 2Negahdar Hosseinpour
1Institute of Petroleum Engineering, Tehran University, Tehran, Iran
2Institute of Petroleum Engineering, University of Tehran, Tehran, Iran
3PhD Condidate
4Institute of Petroleum Enginnering, University of Tehran, Tehran, Iran
5Institute of Petroleum Engineering, University Of Tehran, Tehran, Iran
Previous studies have proposed different mechanisms responsible for additional recovery after LoSal injection with a strong focus on wettability alteration as a main mechanism. This study introduces another mechanism underlying LoSal effect known as Marangoni Flow. Investigations indicate that formation water attached to the rock surface forms a solid-like interface with residual oil on the surface. SO_4^(2-) ions adsorbing to rock surface and not passing through layer of formation water plus selective passage of other ions and water itself suggests membrane-like behavior of this layer which results in a flow known as Marangoni flow. This is caused by an interfacial tension (IFT) gradient between two existing interfaces, one between formation water and oil, and the other between oil and injection water. Effect of this flow is observed by groups of tests including Contact angle and IFT measurements, and precise visual observations using six brines with different salinities as injection water and two formation water differing in salinity. Brines comprise six types of salts: NaHCO_3 , NaCl, Na_2 SO_4 , MgCl_2.6 H_2 O, CaCl_2, KCl with different salinities from high to low. Results suggest Marangoni Flow as one of the first mechanisms causing additional oil recovery immediately after smart water injection before the influence of wettability alteration and IFT change.
Marangoni effect, wettability, interfacial tension, smart water, enhanced oil recovery
Status : Paper Accepted (Oral Presentation)