v.1. Exploration. -- v.2.Processing,interpretation and reservoir engineering. -- v.3. Geophone .-- v.4 Production .-- v.5. Geochemistry , petroleum geology and petrography . -- v.6. Surveying , geophysical field system, seismic stratigraphy and log analysis of subsurface geology . -- v.7. Drilling and drilling fluids ,well cementing, production and transport of oil and natural gas .-- v.8. Petroleum prospecting , petrography and vertical seismic profiling.