| Popis: |
For the prediction and elimination of complications in the drilling process is considered a number of examples of the three-dimensional geomechanical model and of the near-wellbore model in order to optimize the trajectory and design of the wells. During the well trajectory planning, the key point is to forecast and minimize all possible risks associated with both geological, mechanical conditions and technological parameters. An optimal solution can be obtained with the use of a detailed geomechanical analysis. It is shown that in a number of cases, the numerical model of the near wellbore zone is more informative, in comparison with the analytical solution. The result of drilling risks minimization with help of geomechanical analysis tools is presented. A number of recommendations on wellbore construction and stability are established of the comprehensive geomechanical analysis. The discontunities that are derived of seismic field analysis are also included in the review. The image analysis, 1D geomechanical modelling, of seismic field analysis, near-wellbore numerical simulation and full 3D goemechanical modelling were used as a geomechanics tools to optimize "fishbone" trajectory. Microimages help to determine the presence of cavernousness, natural and induced fractures, geological boundaries and bedding planes. Especially useful is a tool for determining the presence of collapse in the areas of kick-off sidetracks. 1D geomechanical modeling helps to determine favorable intervals for shearing and optimal mud density. To assess the risks during the sidetracking operation, a statistical analysis of the actual data was carried out taking into account the spatial orientation of the sidetrack and the direction relative to the currently acting stress state. Stresses and gradients of caving in the intervals of cuts are refined by the near wellbore model. |
