Properties of Natural Gases: typical compositions. Equations of state: general cubic equations, specific high accuracy equations. Use of equations of state to find residual energy properties. Gas Compression: positive displacement and centrifugal compressors; fans. Calculation of poser requirements. Compressible Flow in Pipes: fundamental equations of flow: continuity, momentum, energy equations. Isothermal flow in pipes: the Weymouth equation. Static and flowing bottom-hole pressures in wells. Fundamentals of Gas Flow in Porous Media: Steady-state flow equations. Definition of pseudo-pressure function. Gas Flow in Cylindrical Reservoirs: general equation for radial flow of gases in symmetrical homogeneous reservoirs. Non-dimensional forms of the equation; derivation of coefficients relating dimensionless to real variables. Infinite reservoir solution: pseudo-steady-state solution. Gas Well Deliverability Tests: Flow-after-flow tests: prediction of IPR curve and AOF for the well. Isochronal tests. Drawdown tests: need for data at two flow rates.