Feiyu Wang¹, C. George Simon², Ahmed Manzur², A. Quezada Robinson², Keyu Liu², Shuichang Zhang³, Digang Liang³

(1) Petroleum University, Beijing, China
(2) CSIRO Division of Petroleum Resource, Sydney, Australia
(3) Research Institute of Petroleum Exploration and Development, China National Petroleum Corporation, Beijing, China

ABSTRACT: Validation of source kitchens and petroleum charge history in complicated basin using fluid inclusion: an example from Tazhong 4 oilfield in central uplift, Tarim Basin

Tazhong 4 Paleozoic oil fields is the most prolific oil-producing area in the Tarim cratonic basin, several possible petroleum migration and accumulation scenarios were existed in explaining its source and charge history, because there were two putative source rocks and hydrocarbon kitchens, multiple phases of hydrocarbon generation. The controversial focus were whether a significant petroleum charge from vast Cambrian source kitchens to Carboniferous sandstone reservoir existed at the earlier time (Permian). oil inclusion in diagenitic minerals, which represent pristine petroleum presented in the trap in the earlier times, were systematically studied from TZ402 well using microthermometry, GOI and MCI methods, and compared with present crude oils. The molecular fingerprints of inclusion oils were similar to the DST oils, both can correlated with the Upper and Middle Ordovician source rocks. The maturity order based on aromatic fraction reflected a relatively lower maturity of fluid inclusion oils than corresponding DST oils in Carboniferous CIII reservoir intervals., which imply fluid inclusion oils in CIII filled in earlier time. The presence of 25-norhopane with integrated n-alkane distribution in fluid inclusion oils and DST oils deny multiple phases charges in Carboniferous sandstone reservoir, some palaeo-biodegraded oils in Silurian sandstones were incorporated during petroleum migration from Upper and Middle Ordovician source kitchen to Tazhong 4 structural trap. Geochemical and petrological evidences indicate that the petroleum in Carboniferous reservoirs were charged from upper and middle Ordovician source kitchens after Cretaceous, there were no significant contribution from lower and middle Cambrian source kitchens.

AAPG Search and Discovery Article #90906©2001 AAPG Annual Convention, Denver, Colorado