Swelling Study of Bentonite Clay: Application in Petroleum Industry

Abstract

Up to 97% of hydrocarbon producing reservoirs contain clay minerals. Different type of clay minerals (Smectite, Kaolinite, Illite, Chlorite) presents in reservoir with different properties like Cation Exchange Capacity. If the chemical activity and chemical compounds of the clay are analyzed, then it helps to understand clay interactions with differ saline water taking place in the reservoir which causes many problems during drilling, completion, Enhance Oil Recovery and Production. Bentonite (smectite) is one of the most commonly used minerals in drilling fluids and also present in reservoirs. For this study, Bentonite sample obtained from Gumpro Drilling Fluids Pvt. Ltd. W. Mumbai was characterized using FTIR spectrophotometry and XRD techniques. The main peaks of bentonite of Al-OH, AlO and Si-O functional groups in the high frequency stretching and low frequency bending modes were reflected in the infrared spectra. The XRD results identified montmorillonite as the major mineral phase with confirmed presence of quartz and kaolinite as minor quantities in the samples. For the swelling nature study, bentonite was treated with various saline solution (2%, 4%, 6%, %8 by wt.) of 50 ml NaCl and CaCl2 solution. Swelling Study was done in determine the effect of salinity on clay volume change, settling time and type of settling whether disperse or flocculate. Swelling study shows more effectiveness of NaCl on Bentonite as compare to CaCl2. Change in d-spacing value of bentonite in XRD diffractogram shows the swelling of bentonite. FTIR also conforms the swelling and some structural change by the change in wave number. Zeta Potential also conforms the swelling effect by giving change in value. The zeta potential of bentonite was also found to be sensitive to the valence of ions in solution which resulted in zeta potential of bentonite NaCl treated bentonite solution which more negative than the untreated bentonite solution. However, zeta