Premium
Precipitation of sparingly soluble salts in packed sandbeds in the presence of miscible and immiscible organic substances
Author(s) -
Pavlakou Efstathia I.,
Sygouni Varvara,
Lioliou Maria G.,
Koutsoukos Petros G.,
Paraskeva Christakis A.
Publication year - 2016
Publication title -
crystal research and technology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.377
H-Index - 64
eISSN - 1521-4079
pISSN - 0232-1300
DOI - 10.1002/crat.201500267
Subject(s) - supersaturation , calcium carbonate , chemistry , aqueous solution , precipitation , carbonate , salt (chemistry) , chemical engineering , inorganic chemistry , mineralogy , organic chemistry , physics , meteorology , engineering
Sparingly soluble salts precipitation, e.g. calcium carbonate or calcium sulfate, results in pore clogging in rock formations and in the concomitant reduction of the local permeability of oil wells during the oil extraction processes. On the other hand, in situ controlled salt precipitation is desirable in various applications e.g. waterproofing of concrete constructions suffering from leakages, etc. In the present study, calcium carbonate (CaCO 3 ) precipitation in sandbeds was investigated, in the presence of organic solvents simulating the conditions prevalent in oil‐well zones. CaCO 3 precipitation was investigated from supersaturated solutions prepared by in‐situ mixing of NaHCO 3 and CaCl 2 .2H 2 O solutions before the inlet of sandbeds. The solution resulting from the mixing of the two solutions was supersaturated with respect to all calcium carbonate polymorphs. Three types of experiments were performed depending on the supersaturated solutions: a) aqueous solutions b) aqueous supersaturated solutions in contact with sandbeds pre‐saturated with n‐dodecane c) aqueous solutions containing monoethylene glycol (MEG). Results showed that oil–water interfaces enhanced the heterogeneity of the supersaturated solutions and accelerated crystal growth of calcium carbonate at the inlet of the sandbed, resulting in early pore clogging and limitation of local permeability. Maximum sandbed consolidation was obtained with the solutions containing MEG.