Geomechanical Analysis and Modelling for Optimizing Well Trajectories in the Reservoir

Drilling of complicated well trajectory in the reservoir has been increased. Multilateral wells, traditional horizontal wells and highly deviated boreholes are drilled frequently. Therefore, borehole stability of the drilled reservoir becomes more important. Failure to estimate the geopressures to determine safe mud weight for drilling can jeopardize drilling works. In addition, the lack of understanding of the mechanical properties of the reservoir rock to be drilled will only create more drilling problems. Thus, for maintaining wellbore stability of well trajectories, it is important to make geomechanical analysis as a tool to make sure the mud weights are suitable. Also, by being equipped with the knowledge of rock mechanics of the reservoir will ensure the any rock failures while drilling can be predicted beforehand. Therefore, geomechanical analysis and modelling using PetrelTM would be the best method to predict the mud weights and to study the geomechanics of the reservoir such as the in-situ stresses, the coefficient friction factor that if is exceeded will trigger fault reactivation, unconfined compressive strength (UCS) of the rock to determine whether the rock is brittle or ductile, the Young’s Modulus (E) and also Poisson’s ratio (í) to predict the deformation of the rocks under stress. When the mud weight used are within the safe mud window, drilled trajectories will not experience any compressive failure or formation breakdown. Besides that, if rock failures are predicted beforehand, drilling the reservoir would not be a problem as deformation of the reservoir will be avoided. If the drilling is smooth, it is said that the new well trajectories drilled are successfully optimized.