Geomechanical modelling and numerical stability analysis of an Oil field wellbore

The analysis and prediction of the wellbore instability potentials, is of important and critical factors in oil wells’ whether in drilling or completion phases. Parameters affecting well stability include different geomechanical parameters including strength parameters of rock mass and in situ stresses, that are counted as uncontrollable parameters and second group of parameters consisting of drilling fluid pressure, drilling direction and induced stresses which are developed after drilling, are considered as controllable parameters. This paper investigated well instability problems in one of the Sarvak pay zone wells in one of the Iranian west oil fields. To achieve induced stresses around the wellbore, a finite element numerical analysis was used with considering variations of rock mechanical parameters. Furthermore, wellbore stability, investigated by using Geomechanical modelling established by empirical equations. Finally, the results of analyses were compared to real data gathered from drilling and casing information, in order to analyze the accuracy of the results.

Keywords:

Geomechanical modelling , Numerical analysis , Geomechanical Parameters , Induced stresses , Sarvak Pay zone