Theory and Numerical Applications. Multiphysics modeling has been widely applied in the petroleum industry since the 1970s. The rapid development of computer technology has enabled the numerical applications of multiphysics modeling in the petroleum industry its applications are particularly popular for the numerical simulation of drilling and completion processes. This book can be used as a manual of typical examples and modeling skills for numerical engineers in petroleum engineering it includes numerical examples from drilling and completion practice, as well as an introduction of key numerical modeling skills.