Tarim Basin East - Full Engel Sue Area Silurian Sedimentary Facies And Reservoir Characteristics Research

According to current exploration and research in Silurian of Mandong-Yingjisu district in Tarim basin, making full use of the available geological, geophysical exploration, drilling and comprehensive research material, directed by sequence stratigraphy, seismic stratigraphy and sedimentation, on basis of stratigraphy division, combining seismic facies types, sedimentation system, characteristic of reservoir and reservoir influence factors is studied and reservoir quality was evaluated.Through comprehensive analysis of the sedimentary facies symbol in Silurian of12key wells,such as the rock type, mudstone color,bedding structure, authigenic mineral,sedimentary structure,biological fossils,biological remains and well logging curves to identify high-energy sandy shore facies, non-barrier tidal flat facies, shallow water shelf facies and braided river delta facies. There are4types of sedimentary facies,10subfacies and15kinds of sedimentary microfacies in this study areas. Based on the research on sedimentary microfacies, combined characteristic of seismic facies and sedimentary system plane distribution, characteristics of vertical evolution of Kepingtage group, tataaiertaer group,yimugantawu group in Silurian is systematically studied.The deposition conditions are the basic factors that control reservoir development.By the analysis on depositional system,The four reservoir types may be recognized in the study area:braided fluvial deltaic reservoirs sandbody. tidal-flat sandstone reservoir sandbody,coastal reservoir sandbody and turbidite fan reservoir sandbody.The different sandbody genesis and later diagenetic transformation shape the different characteristics of the reservoir.The sandbody in the same region have the similar reservoir characteristics.the same sandbody in the different regions have great difference on reservoir characteristics. All kinds of sandbody reservoir properties in Silurian is rank as follows:tidal flat sand body is better than the delta of braided distributary channel sand body, plain braided distributary channel sand body better than the leading edge of underwater distributary channel sand body.Three sedimentary sequences in the Yingjisu region of Silurian can be used as reservoirs.The reservoir of the sequence2is slightly better than the sequence3and the quality of the sequence1is the worst. Except for the sequence4,all the sequence can be used as reservoir in Mandong region in Silurian. but the reservoir quality is poor, almost reservoir is type IV. There is type III in sequence2, relatively speaking, the reservoir quality in sequence2is better than the other two-layer sequence.The worst sequence is sequence3. Reservoir physical properties of Mancan1well of Silurian is classified as type Ⅳ. Cao1well in Silurian is basically shallow continental shelf sedimentation which identified as non-reservoir.sequence2and sequence3is the most favorable reservoir in the region.