The Baoshan Field Newly Department Yangyi High Resolution Sequence Stratigraphy Study

Using the principles and the technique methods of high resolution sequence stratigrphy represented by T. A. Cross, with the raw data researched deeply of Baoshan basin and parts of early research achievements, basing on surface outcrop data, well core data and electrofacies analysis of coring well, this paper carefully analyzed characters of strata sequences and sedimentary facies in Baoshan terrigenous oil-gas bearing basin and researched deeply features of petrology, sedimentology and high resolution sequence stratigraphy of main formations(the second and the third members of Yangyi formation). On the basis of these researches it further divided sand formation, individual reservoir and single sand-body, and proceeded high resolution tracing correlation of single sand-bodies that were placed at isochronous stratigraphic correlation framework of Sssc- or Ssc- or Msc-seqences, and discussed the distribution and the development of depositional microfacies of single sand-bodies.According to surface outcrop in the perimeter areas of Baoshan basin, regional geology settings, core record, the data of drill and logging, electrofacies analysis, it was thought that the main sediment resource of the second and third members of Yangyi formation in Yongzhujie convex in Baoshan basin originated the Palaeozoic and Mesozoic formation in the western side of Baoshan basin and deposited in the environment of fan-delta and lake. In accordance with features of petrology, sedimentary structure, profile structure, electrofacies and seismic facies, underwater distributary channel, frontal sill-like sand, mouth bar, distal bar, front fan-delta mud and mere mud and so on, were identified, and depositional features of them in detail were discussed respectively.With the principles and the technique methods of high resolution sequence stratigrphy, characters of high resolution sequence stratigraphy of them were studied in detail. The gas-bearing formation were two relatively entire long term cyclic sequences, and five middle-term base-level cyclic sequences, fourteen short-term base-level cyclic sequences and thirty-one super-short-term base-level cyclic sequences were recognized in the third member of Yangyi formation. And four middle-term ones, sixteen short-term ones and thirty-three super-short-term ones in the second member of Yangyi formation. This paper took middle- and short-term base-level cycles as correlation framework and took super-short-term ones as strata correlation units. Therefore the high resolution sequence stratigraphic framework and the high resolution isocorrelation of the second and third members of Yangyi formation were established. The deepening-up asymmetrical type (i.e. type A) and the symmetrical type(i.e. type C) were identified in the super-short-term cycles and the short-term ones. This paper discussed delicately depositional sequences and stacking patterns of different structure types of short-term and...