Petroleum technology 98 Tecnologa̕ del petrl̤eo Industria del petrl̤eo 78 Petroleum industry 78 Petrl̤eo 49 Crudos pesados 43 Oil 33 more ... Heavy crude 26 Environment 21 Medio ambiente 21 Industria petroqum̕ica 20 Petrochemical industry 20 Petroleum refining 20 Refinacin̤ del petrl̤eo 20 Petroleum 19 Properties 18 Propiedades 18 Gas natural 17 Natural gas 17 Energy sources 14 Fuentes de energa̕ 14 petrl̤eo 14 Viscosidad 13 Viscosity 13 crudos pesados 13 Energa̕ 12 Energy 12 Yacimientos de petrl̤eo 12 heavy crude oil 12 oil 12 less ...