Investigation on Oil Physical States of Hybrid Shale Oil System: A Case Study on Cretaceous Second White Speckled Shale Formation from Highwood River Outcrop, Southern Alberta

Nine samples collected from the Upper Cretaceous Second White Speckled Shale Formation at Highwood River outcrop in southern Alberta were geochemically characterized for their oil contents, physical states, and chemical compositions. Cold extraction was performed on 8–10 mm 2–5 chips sequentially to obtain first second extractable organic matter (EOM-1 EOM-2), while Soxhlet powder previously extracted third extract (EOM-3). EOM-1 can be roughly regarded as free EOM-2 is weakly adsorbed mineral surfaces, EOM-3 may represent strongly kerogen. While both yields Rock-Eval pyrolysates differed original values due evaporative loss during outcropping, there a generally positive correlation between total EOM derived pyrolysis. linearly correlated with S1, S2 content well of TOC, suggesting that TOC main constraint oils. A bulk composition analysis illustrated contained more saturated hydrocarbons, enriched resins asphaltenes. More detailed fractionation oils demonstrated by molecular compositions each using quantitative GC-MS analysis. Lower-molecular-weight n-alkanes smaller-ring-number aromatic compounds preferentially concentrated compared higher-molecular or greater-ring-number counterparts vice versa EOM-3. Fractionation isoprenoids adjacent eluted n-alkanes, isomers steranes, hopanes, alkylnaphthalenes, alkylphenanthrenes alkyldibenzothiophenes insignificant, no allogenic charge deep strata. Strong hydrocarbon fractions observed apparently retained hydrocarbons. However, difference state less dramatic than variation shales siltstones. Lithological heterogeneities controlled amount fluids. Oil resided (source rock) behaved similar EOM-3, diffusive expulsion leading release discrete molecules occluded phase siltstones connected pores and/or fractures (reservoir). Under current technical conditions, only flow will recoverable resource. Therefore, highest potential expected intervals organic-rich beds. The compositional variations primary migration source rocks reservoirs present study contribute better understanding distribution hydrocarbons generated stored within shale plays.