Evaluation of polyacrylamide/clay composite as a potential drilling fluid additive in inhibitive water based drilling fluid system

The troublesome shale formations need special formulation of drilling fluids having high shale inhibition characteristics to mitigate wellbore instability problems. In the present study, polyacrylamide/clay nanocomposite (PANC) was synthesized and used as drilling fluid additive. The free radical polymerization technique was adopted for the synthesis of the nanocomposite and it was characterized by Fourier transform infrared spectroscopy, field emission scanning electron microscopy, and thermogravimetric analysis. During the synthesis, clay to monomer ratios were varied and the effect of synthesized product on the rheological and filtration properties of the drilling fluid system was studied thoroughly. Finally, most suitable grade of PANC was utilized as a drilling fluid additive and its effect on the shale recovery was studied and compared with partially hydrolyzed polyacrylamide, a frequently used shale encapsulator. The experimental investigations revealed that PANC exhibited superior shale encapsulation property than partially hydrolyzed polyacrylamide (PHPA). Hence, synthesized nanocomposite may be used as a drilling fluid additive in inhibitive water based drilling fluid system.