FazlinTamboesai, Emrizal MSophia, Halida2016-05-022016-05-022016-05-02wahyu sari yenihttp://repository.unri.ac.id/xmlui/handle/123456789/8327In this study, crude oil samples from Petapahan were tested and characterized with isoprenoid parameters. Determination of thermal maturity level aims to determine the feasibility of petroleum wells to be exploited because there are many new wells of petroleum unexploited in the Riau area. Determination of maturity crude oil performed by analysis saturated fractions. Saturated fraction of the wells petapahan used to determine the maturity of crude oil based on parameters isoprenoid, n-alkane and carbon preference index were analyzed using gas chromatography-flame ionize detector (GC-FID). Based on the value Pr / Ph, Pr / n-C17, Ph / n-C18 and its CPI, the maturity level of petroleum from oil wells Petapahan, Langgak and Pendalian ripe with order levels of maturity and quality of the oil is oil Petapahan> Langgak> Pendalian as indicated by the value of Pr / Ph (2.29; 2.27; 2.29), the value of Pr / n-C17 (0.44; 0.57; 0.44), the value of Ph / n-C18 (0 , 20; 0.22; 0.25) and the CPI (1.095; 1.087; 1.069) respectively.enPetroleum Petapahancarbon preference indexisoprenoidstudent Paper Post Degree