Mechanical and physico-chemical aspects of wellbore stability during drilling operations

One of the problems during drilling operation is wellbore instability. Many parameters affect the wellbore stability. Some of these parameters are related to the properties of drilling mud and its interaction with the formation and some of them are related to the mechanical properties of the formation and the magnitude and distribution of the forces around the wellbore. Generally the wellbore instability is calssified as mechanical, physico-chemical or both. This paper is an attempt to investigate the mechanical and physico-chemical aspects of wellbore stability during drilling operations

► In situ stresses existing in different layers of rock.
► The mechanical properties of rock.
► Variation of pore pressure.
► Mud weight.
► Mud chemical composition.