Disappearance and Appearance of Cations during Modified Low Salinity Waterflooding by Ammonium Ion in Shaly-Sandstone Formation
H. Vu Quoc and F. Srisuriyachai
Event name: 81st EAGE Conference and Exhibition 2019
Session: Poster: Production and Management EOR A
Publication date: 03 June 2019
Info: Extended abstract, PDF ( 914.81Kb )
Price: € 20
Several previous studies have shown that low salinity waterflooding involves three main mechanisms which are fine migration, pH rising and Multi-component Ion Exchange (MIE). MIE was mentioned as a major technique in enhance oil recovery by using monovalent ion to expel divalent ions, as a bridge between oil droplets and rock surface. Ammonium ion is a positively charged polyatomic cation and it has several properties in common with potassium ion such as hydrated number and ionic diameter. These properties may favor MIE mechanism during low salinity waterflooding. This study is performed to evaluate abiity of ammonium ion in replacing divalent ions in shaly-sandstone. Comparison of effectiveness of ammonium ion and potassium ion was also made. The results show that ammonium ion can displace both calcium and magnesium ions from shaly-sandstone. Moreover, combination of ammonium ion and calcium ion in injected water can also favors dissolution of magnesium ion. It can be concluded that hydrated properties of ammonium ion have a decent influence on the MIE mechanism. It can also be noted that potassium ion, as a monovalent ion, is more complicated than ammonium ion as it can be found in both injected water and mineral surface.