: A technical course document from PDH Online that explains drilling, completion, and hydraulic fracturing fluids in detail. Business & Project Management

: A free resource from DrillingFormulas aimed at explaining the industry to friends, family, and new starters. Oil and Gas Production Handbook - ABB

Perfect for newcomers or those who need a high-level overview without the heavy math:

: A "must-have" classic available on Malecentrum that serves as a one-stop tool for both new and veteran engineers.