Tidal bore is hydraulic jump during the process of tide flooding with the tide wave moving upstream. They are widely distributed in the estuary zone with high tidal range and funnel-shaped planeform. Tidal bore deposit study is important for further understanding about paleogeomorphology, paleoenvironment, paleoclimate of areas near the estuaries, and sandbody formed by tidal bore deposit could be potential oil and gas reservoir. Researches about tidal bore have been always concentrated on hydraulic characteristics of tidal bore and its influences on estuary environment and engineering, while the study on tidal bore deposit is rarely reported. One of the most important causes is the complex hydrodynamic conditions in the estuary zone. Deposits characteristics is complicated in this zone due to comprehensive effects of river flow, waves and tides. It is hard to affirm the preservation probability of tidal bore deposits, especially in the ancient rock record. In view of this, current status and forecast about tidal-bore deposit study were expounded in this study based on comprehensive summary and discussion about typical tidal bore deposit data and reports. Criteria for recognition of tidal-bore deposits were described in detail on the aspects of sedimentary structures, grain size distribution, and facies model. One of the most critical diagnostic marks of tidal bore was a special undulating erosion surface with a series of irregular and stepped excavations on it. This surface was formed by cyclic pressure loading induced by the passage of a tidal bore. In addition, the cross-bedding inclined upstream, soft sediment deformation structures and massive sandstone on the erosion surface were also important marks of a tidal bore deposit. Problems existing in current research were discussed and some suggestions were proposed. Various methods and technology should be used to perfect tidal bore facies model, and research on diagenesis and reservoir features of sandbody formed by tidal bore should be strengthened in the future. Sandbody formed by tidal bore of different types (breaking tidal bore and undular tidal bore) should be distinguished to deepen the understanding of their various hydrodynamic conditions and reservoir scale. Tidal bore is significant geological process in estuary zone, and deposits formed by it makes great influence on the geomorphology of this area, which should be paid more attention. 相似文献
<正>1 Introduction As new exploration domain for oil and gas,reservoirs with low porosity and low permeability have become a hotspot in recent years(Li Daopin,1997).With the improvement of technology,low porosity and low 相似文献
<正>1 Introduction Reservoir architecture analysis of distributary channel of Daqing oilfield has drawn consistent interest among development geologists and petroleum engineers over the last decade(Lv et al.,1999;Zhou et al.,2008;Zhang et 相似文献
It was showed that understanding of the diagenetic modifications and its associated products in the deeply to ultra-deeply buried tight sandstone reservoirs (DUDTSR) is great important for reservoir characterization and hydrocarbon prediction. However, the fine characterization of diagenetic evolution via geologic modelling in tight sandstones remains a great challenge as for complexity of lithology, temperature, pressure and formation fluid throughout the entire life cycle of tight sandstone reservoirs. To help get a comprehensive idea of the distribution of diagenetic processes on the formation of DUDTSR in the long geological period, type-I and type-II fine sections of diagenetic stage for clastic reservoirs were creatively proposed and its essence was illustrated using the Paleogene Huagang (E3H) Formation in the southern Xihu Sag. Through combination of both quantitative and qualitative methods which began with current formation temperature, vitrinite analysis, illite and I/S mixed layers based on analytical testing of the E3H Formation, (1) Paleotemperature (T), vitrinite reflectivity and smectite in mixed layer during burial processes were restored based on numerical analysis, (2) The accurate division of diagenetic evolution was identified from coarse to fine process using new model, (3) And finally the geological significance of fine division of the conventional diagenetic stage was illustrated for low-porosity and tight sandstone reservoirs.