Geochemical study and significance of sequential extraction in reservoir rocks of Turpan-Hamin Basin

摘要

Seven samples collected from the Turpan-Hamin Basin were treated by sequential extraction method. Analytical results indicate that the free oils, inclusion oils (oil-bearing fluid inclusions) and day-adsorbed oils vary significantly. The geodiemical characteristics of inclusion and clay-adsorbed oils correlate well with the lacustrine mudstones. The characteristics are as follows: (i) with higher PhC_(18) ratio and lower Pr/Ph ratio; (ii) with higher values of C_(26) tricyclic/C_(23) tetracyclic terpane, C_(23) tricyclic terpane/(C_(23) tricyclic terpane+C_2(17a(H) hopane), C_(29)/(C_(21)+C_(29)) terpane, Ts/Tm and C_(21)+C_(29)17cx(H) norhopane and lower value of C_(21)+C_(29) tricyclic terpane; (iii) with relatively high content of C_(27) and C_(28) sterane and lower abundance of C_(29) sterane and diasterane. They indicate that the early charged oils are derived from the pre-Jurassic lacustrine mudstones and the later charged oils are from the Jurassic coal-bearing strata or coals.