Contents Chapter 1 The basic principle of percolation mechanics in porous medium 1. Static conditions in reservoirs 1. 2 The driving forces and driving mechanism in reservoir The basic law of seepage flow Darcy's law 4 The limitations of Darcys law and non-Darcy seepage flow Chapter 2 Steady seepage flow of single-phase incompressible fluid 2. I Three basic seepage flow modes 2.2 The planar one-dimensional steady seepage flow of single-phase incompressible 18 2.3 The planar radial tluid flow of single-phase incompressible fluid 2. 4 The incomplete well 5 The systematic well testing( Step rate testing 2. 6 The diflerential equation of single-phase fluid seepage flow Exercises Chapter 3 The interference theory of oil well under rigid water driving 3. I The phenomenon of well interference 2 The superposition principle of potential 3.3 The image retlection method 4 The application of complex function theory to the planar seepage lield Exercises Chapter4 The unsteady seepage flow of slightly compressible fluid 4. I The physical process of elastic fluid seepages towards wells 4.2 The planar one-dimensional unsteady seepage flow in semi-infinite formation . .......95 4.3 The law of pressure transient of clastic fluid unsteady seepage flow toward a well 4.4 The approximate solution of pressure change of fluid seepage flowing towards well in finite closed elastic formation 4.5 The multi-well interference of elastic unsteady seepage flow 4. 6 The unsteady well testing analysis cercis II8 Chapter 5 The seepage law of natural ga 121 5. I The properties of natural gas and its basic differential equation of seepage flow . .,121 5. 2 The steady seepage flow of gas