Study On The Sedimentary Systems And Sequence Stratigraphy Of Es2-Es3 In Gunan Sag

Based on the theories of continental sequence stratigraphy and sedimentology, and the means of logging, seismic and geology, this paper studied the paleoprovenance, the sedimentary system and sequence stratigraphy of Sha2-sha3 sections in Gunan Sag. The thesis is based on plenty of seismic data, drilling data, logging data and the others.According to the typical sequence stratigraphy, combined with the high-resolution sequence theory, sequences of Gunan Sag were to be devided. In the objective layer of the work area, 6 sequence-boundaries and 5 third-order sequences (long-term base-level cycles) were identified. Further, the third-order sequences were divided into 9 forth-order sequences (medium-term base-level cycles). Based on the medium-term base-level cycles unit, we established the time-strata frameworks of Sha2-sha3 of the Gunan Sag. Depending on the depositional characteristics of stratum, some special characteristics in strata, heavy minerals and so on, paleoprovenance area of Gunan Sag can be determined. Based on detailed single well facies analyses and the across-well analyses,according to provenance analyses and the structural setting, the paper recognized 3 types of sedimentary systems, including delta system, subaqueous fan system and lacustrine system. Delta system mainly contain fan delta faces and Braided delta faces. Fan delta faces were mainly developed in the eastern area of the sag near the Kendong uplift. Braided delta faces were mainly distributed in the regions near the west part of Gudao uplift and Chenjiazhuang uplift. Subaqueous fan system mainly contains near-shore subaqueous fans and fluxoturbidite. Near-shore subaqueous fans were mainly developed in the northern region of the sag near the major controlled-faults. Fluxoturbidite were mainly distributed in the front of delta or near-shore subaqueous fan in the deep-lake area.The paper raised the form of provenance intersected and overlapping in the light of the situation of provenance intersected in Gunan Sag, The form mainly contain cross-touching style and package style. According to the form, the article exactly analysised provenance area relation in the synthetic of sedimentary facies in Gunan Sag. Finally, combined all the geological characteristics, the paper established depositional model of Gunan Sag and predicted the distribution of the favorable reservoir of this area.