Molecular compositions of weathered petroleum and comparison with its possible source

摘要: Abstract Two surface outcrop samples and three drill core of oil-impregnated sandstone from the P.R. Spring Seep, Uinta Basin, Utah were analyzed. These oils exhibit in common entire homologous series tricyclic diterpane hydrocarbons, which have been previously described only extracts Mahogany Ledge Member Green River Formation. Hopane a degraded hopanes are also present oil samples, while steranes conspicuously absent. Aliphatic alkanes deepest sample. The cycloalkanes apparently not readily utilized by petroleum oxidizing microbes, therefore survive weathering process. Tricyclic tetracyclic alkylated diterpanes unchanged, whereas norhopane through tetrakisnorhopane may be interpreted as progressive bacterial degradation hopane molecule. occurrence distribution diterpanes, pentacyclic triterpanes is similar to stratigraphically nearby Member, suggesting that shales source rocks for now exposed Seep. absence steranes, abundant shales, puzzling.