Abstract Tortuosity occurs when a well deviates from a straight hole. The most commonly known tortuosity is the local dogleg severity variation associated with the use of steerable motors in "slide/drill/slide" drilling. However, there is a tortuosity that exists in many wells, which the authors will refer to as "micro-tortuosity" in which the hole axis is a spiral instead of a straight line. This paper presents a study of micro tortuosity using field data from the North Sea wells. The friction factors and tortuosity index are used to quantify the effect of tortuosity on the torque and drag. The results show that hole spiraling, associated with the use of conventional short-gauge bits, is a major contributor to today's friction factors used in the torque and drag model.