Investigation on Bentonite and Its Compatibility with Cationic Surfactant for an Effective Permeability Modifier

Natural swelling ability and low cost have made bentonite preferable material for improved oil recovery such forming viscous water suspension. In Improved oil recovery (IOR) projects, poor volume sweep efficiency in heterogeneous reservoir limits its success. One of the IOR methods which of recent interest is permeability modifier method. Conventional blocking agent such as bright water and micro gel based on polymer cannot be applied at high temperature. Therefore, bentonite is proposed as a blocking agent because it can withstand high temperature conditions. However, bentonite has tendency to coagulating before it could penetrate the wellbore when in contact with water. Thus, cationic surfactant such as n-dodecyltrimethylammonium bromide (DTAB) is proposed as an additive in bentonite solution to overcome this problem. Laboratory experiments has been conducted in this study to determine the most stable modified bentonite solution before it is analysed in core flooding test. This study found that, the most stable bentonite solution is 20μm nanoclay with 13.7x10-3mmol/kg of DTAB. It is able to reduce the liquid permeability of the core in about 64% from original permeability. Indeed, modified bentonite solution has the potential to be used as a blocking agent in a permeability modifier method.