--> Abstract: Quantitative Estimate of Residual and Palaeo Oil Columns to Trace Oil Migration and Accumulation: Case Studies from Panyu Upli; #90063 (2007)

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Quantitative Estimate of Residual and Palaeo Oil Columns to Trace Oil Migration and Accumulation: Case Studies from Panyu Uplift in the Pearl River Mouth Basin, South China Sea

 

Wang, Feiyu1, Yulei SHi2, Huasen Zeng1, Keyu Liu3, Hesheng Shi4 (1) China University of Petroleum (CUP), Beijing, China (2) China University of Petroleum (CUP), Beijing, Colombia (3) CSIRO Petroleum, Bentley, WA, Australia (4) CNOOC Limited, Guangzhou, China

 

Only some commercial gas fields were discovered in the Panyu uplift Pearl River Mouth Basin, South China Sea, which is southwardly abut upon deep water area Baiyun petroleum generative depression. The existence of commercial oil migration and accumulated in Panyu uplift is still controversial, although many geologists presumed that Eocene Wenchang Formation oil-prone lacustrine source rocks and Oligocene Enping Formation gas-prone humic-type source rocks were co-existed in the Baiyun depression. Quantitative estimation of the residual or palaeo oil columns are critical to the accurate calculation of the size of the original reserve and may have important implications for predictive drilling in the surrounding areas. Quantitative grain fluorescence (QGF) and quantitative grain fluorescence on Extract (QGF-E) screen analysis, Molecular Composition of oil inclusion(MCI) were applied to detect the size and putative sources of palaeo-oil zones and current residual oil zones in main carrier beds (T5 sandstones) of 14 wells, Palaeo-oil zones have distinct fluorescence spectra with spectral peaks between 375 and 440 nm and elevated fluorescence intensities compared with spectra for rocks that have always been water saturated. QGF-E and QGF intensities parameter increase upwards from near the current residual oil¨Cwater contact (ROWC) or palaeo oil¨Cwater contact (POWC) to the crest of trap. QGF-E and QGF parameter profiles compared with wireline log data Oil Migration Intervals (OMI) algorithms analysis to determine the cumulative thickness of palaeo-oil zones in T5 sandstones ranging from ca 30m to 100m. Biomarker assemblages of oil inclusions from MCI data indicated oil were originateµÄ from lacustrine source rocks. Those result confirmed that early oil migration and accumulation event and size, later gas displaced the original oils in the Panyu uplift.

 

AAPG Search and Discover Article #90063©2007 AAPG Annual Convention, Long Beach, California