The disclosure relates to a method of conducting a coiled tubing operation. In one implementation, a method includes forming a tubing string, the tubing string having an outer surface. The method also includes applying a coating to an application portion of the outer surface of the tubing string. The application portion includes a portion of the tubing string that will be disposed in a horizontal section of a wellbore, and the coating has a surface energy lower than a surface energy of the outer surface of the tubing string to thereby reduce friction between the tubing string and a casing disposed in the horizontal section of the wellbore as the tubing string is lowered into the wellbore.