PetroWiki was created from the seven volume Petroleum Engineering Handbook (PEH) published by the Society of Petroleum Engineers (SPE). PetroWiki preserves the PEH content in unaltered form while allowing SPE's membership to update and expand content from the published version
Patents are available via many search engines.
An excellent video from University of Central Florida shows how to use CPC (classification) codes to do a more accurate patent search.
Work through solved problems using Schaum's Study Guides.