Well productivity is one of primary concerns in field development and provides the basis for field development strategy.Petroleum engineers often relate the productivity evaluation to the long-time performance behavior of a well, that is, the behavior during pseudo-steady state or steady state flow. This book examines the production performance of oil wells with constant flow rates in different shapes of anisotropic reservoirs, a library of new productivity equations is provided. Wells may be located arbitrarily in an anisotropic reservoir, several combinations of closed and/or constant pressure boundary conditions are considered at vertical and lateral reservoir boundaries. The effects of permeability anisotropy on well performance are discussed. Convenient algorithms to calculate shape factor and pseudo skin factor due to partial penetration are provided. Comparison of different drive mechanisms is presented. Influence of reservoir boundaries on the well responses is investigated. The proposed equations in this book can be used to determine the economical feasibility of drilling a well.