Sedimentary Characteristics And Reservoir Prediction In The Upper Es4 In The Easten Slope Of Niuzhuang Subsag

Between abrupt slope zone and gentle slope zone, there was the eastern slope of Niuzhuang subsag in which it was difficult to understand source, sedimentary system and reservoir distribution in Upper Es4. Aimed at such status, the thesis made full use of manifold data (such as core, well-logs and well logging data, and seismic data, etc), guided by sedimentology of continental petroliferous basin, geology and the theory of sequence stratigraphy, and roundly analyzed sources and sedimentary system. Based on this conclusion, reservoirs were predicted by geophysical techniques. And combined hydrocarbon bearing analysis, the thesis put forward a series of advantageous exploitation objects.High resolution stratigraphic framework for Upper Es4 was established in Niuzhuang subsag, and Upper Es4 was divided into 9 short-term base-level cycles (2 third-order sequence) in ascending order (Es4cx3,Es4cx2,Es4cx1,Es4cs6,Es4cs5,Es4cs4,Es4cs3,Es4cs2,Es4cs1). During sedimentary period of Upper Es4, the sources of sediments were mostly from northeast Qingtuozi swell and southeast Luxi uplift. Southeastern source was mostly in early sedimentary period of Upper Es4,and northeastern source was mostly in late sedimentary period of Upper Es4. The sandstones were form northeastern source that were interpreted to be inshore under-water fan and sublacustrine fan, and the sandstones were from southeastern source that were interpreted to be meandering fluvial delta and slump turbidite fan. During sedimentary period of Es4cs5 sand unit, sources underwent transformation from southeastern source into northeastern source. As a result, sublacustrine fan and slump turbidite fan were developed simultaneously in study area, which may be the best exploration target in Upper Es4. Based on velocity analysis and forward modeling, there are good relationship between RMS amplitude attribute and sandstone distribution, and average instantaneous phase attribute may be a sensitive indicator for variation of fault,sandstone boundary and thickness, and superimposed reservoir pattern. On these bases, the spatial arrangement of these reservoirs in Upper Es4 can be predicted by using a logging-constrained inversion technique and seismic tracing. 28 sandstone bodies were discovered with area of 34km2 in Es4cs5. Study showed that reservoir in Upper Es4 was mainly self genetic-self storage, and physical properties of sandstone reservoirs and abnormal high pressure were main factors controlling hydrocarbon migration and accumulation. At the same time, dissected typical hydrocarbon reservoirs, discovered lithologic traps were comprehensively evaluated using quantitative evaluation of petroliferous properties in sandstone lithologic traps. These provided reliable basis for reserves estimation and well placement. During practice in the eastern slope of Niuzhuang subsag, significant exploration benefit was exhibited.