Drilling fluids are considered as blood of drilling industry for the extraction of oil and gas. Many chemical additives are employed to formulate drilling fluids, but water-soluble polymers play vital role to adjust rheological and filtration properties. Natural and conventionally used polymers in drilling fluids show degradation at high temperature drilling applications. For this purpose, a novel copolymer based on N-Vinylcaprolactam and acrylamide monomers was synthesized for high temperature application of drilling fluids. The chemical structure of polymer was analyzed using Fourier transform spectroscopy, 13C NMR spectroscopy and X-ray photoelectron spectroscopy to study the interactions of monomers. The morphological properties of copolymer were determined using scanning electron microscope and transmission electron microscope. Thermal stability of synthesized novel copolymer and individual monomers was evaluated by thermogravimetric analysis. The suitability of copolymer for drilling fluid formulation was determined by performing rheological properties with different concentrations (0.1 wt.% to 1.5 wt.%) at temperature ranging from 50℉ to 400℉. Rheological results showed that novel copolymer has superior properties compared to the conventionally used polymer. The hydration and swelling properties of shale was determined using novel copolymer as drilling fluid additives and results showed superior inhibition properties with novel copolymer under high temperatures. The synthesized novel copolymer with N-Vinylcaprolactam and acrylamide monomers can be used to formulate drilling fluid for high temperature applications.