The Role of Geomechanical Model in Finding Optimum Roller Cone Bit for Drilling of Asmari Formation

drilling bit is an active part among drilling tools and is regarded as the heart of drilling string . Hence selecting the most eddicient drilling bit is one of the important duties of drilling engineers. Finding optimum bit to drill specific formation is a complex process , and different bit selection methods have been introduced for bit performance evaluation in the past decades. the main input parameters for all of bit selection methods rock mechanical properties of formations drilled by bits lithological and rock mechanical characteristics of all formations in an oil well are evaluated precisely through developing a consistent mechanical earth model. as a result, by employing mechanical earth model , drilling engineers can select optimum bit type its components to drill a specific formations. in this paper laboratory testing on cores such as triaxial compressive test , ultrasonic test under confining pressure of reservoir and log data are used to design comprehensive mechanical earth model for asmari formaion in mansuri oil field. the most important outputs of the designed model include depth profile of elastic and rock strength parameters.