Rheological investigation of pickering invert emulsion system for conformance control in high temperature reservoirs

The use of emulsified gel system in high temperature reservoirs is a promising technique for deep reservoir conformance control. The successful implementation of emulsified gel system for conformance control is mainly dependent on emulsion stability. The emulsion system was designed in a way so that it will only breaks once it reaches the desired depth/zone of interest. The gelation time is very much dependent on the emulsion stability. The flow properties of the emulsion system, which is one of its important physical attributes help to determine the gelation time. In this research study the invert pickering emulsion system was developed for conformance control in high temperature reservoirs. The effect of various variables such as different type of mixing method, salinity, type of emulsifier and temperature was studied. The emulsion systems were prepared using three different mixing methods denoted as M1, M2 and M3. Five different aqueous phase with different salinity were used and their effect on the emulsion systems gelation time was studied. The effect of four different emulsifiers i.e., Cloisite 20, Claytone II, Claytone HY and Claytone ER was evaluated. The emulsion systems were also tested at two different temperatures of 80 °C and 95 °C (ambient pressure conditions). In total fifteen different emulsion systems were prepared and tested. The emulsion system with highest salinity and Cloisite 20 as emulsifier was found to be with the longest gelation time of 24306 s (at 80 °C). At 95 °C, the Cloisite 20 as emulsifier and aqueous phase in field mixing water provided highest gelation time of 3362 s. The emulsion system with lowest salinity and Claytone HY as emulsifier was found to be with the lowest gelation time of 1684 s. Increase in temperature tends to decrease the gelation time of the developed emulsified gel system. The emulsion prepared with mixing method 3 (M3) and Cloisite 20 as emulsifier provided a gelation time of 5040 s at 80 °C but the gelation time of the same system is decreased to 3362 s at 95 °C. The effect of mixing method on the gelation time was also studied. Emulsion system prepared with mixing method 1 (M1) gives the gelation time of 7020 s whereas the same emulsion system prepared with the mixing method 3 (M3) gives gelation time of 5040 s.