Conformance Control in Harsh Reservoir Conditions Using a Novel Pickering Emulsion

Abstract

AbstractThis study reports the application of emulsified and non-emulsified colloidal silica gels (CSGs) for conformance control in oilfields. Herein, non-emulsified CSGs were produced from 28% and 20% colloidal silica and sodium chloride (NaCl) of varying concentration from 1 – 10%, while emulsified CSGs were formed from 28% colloidal silica solution, diesel and the optimal emulsifier (cloisite 20 - CL20) following proper selection process and visual observation of gelation activities of different formulations of non-emulsified CSGs. Rheological determination was used to examine how various temperatures (80, 100 and 120 °C) affect the gelation of emulsified and non-emulsified CSGs. Also, effect of varying CL20 concentrations (500, 700, 1000 and 1250 ppm) on the viscosity of emulsified gel was evaluated. Experimental results showed that the gelation times of both emulsified and non-emulsified CSGs decreased with increasing temperature. However, the gelation periods of emulsified CSG at tested temperatures were longer than that of non-emulsified CSG. The complete gelation times of emulsified CSG at 80, 100 and 120 °C were 83 hours, 24.8 hours, and 7.1 hours, respectively; and that of non-emulsified CSG at these same temperatures were 36 hours, 10.5 hours and 6.2 hours, respectively. Likewise, it was noticed from the rheological determination that, as the CL20 concentration is increased, the emulsified CSG viscosity decreased which may hinder its final gel strength. Hence, about 500 ppm of CL20 would be suitable for the formation of an emulsified colloidal silica gel having the desired gelation time and gel strength.