| The sequence stratigraphy and sedimentary facies distribution of Yabus and upper Samaa Formation,Palogue oil-field,3/7 area in Sudan,are studied,which are on the basis of cores,drilling,log and seismic data,also on the basal level as reference plane of high resolution sequence stratigraphy theory and parsing technique.After referring to a regional tectonics and depositional setting,a large number of the past research results and this research,which show that Yabus and upper Samaa Formation in Palogue oil-field is main fluvial facies deposit.Two different Type of rivers - braid river and meandering river are recognized. Braid river sedimentary facies classify as braided channel,bar, overflow, flood plain; meandering river classify as point bar, crevasse splay, crevasse channel and flood plain,which are on the basis of core, electrofacies and seismic facies. Electrofacies template of two different rivers are created,which are on the basis of cores and logs.Referring to fluvial facies of sedimentology and high resolution sequence stratigraphy theory,on the basis of sedimentary microfacies types, phase sequence and facies association recognized,different levels of basal level cycle of key boundary(erosion surface and transform surface) are recognized by change of A/S response to stratigraphy and sedimentology.The Yabus and Samaa II Formation are divided into two long-scale cycles(appromately triple sequence),four four-stage sequence,ten five-stage sequence. To the region four cycles of the results of the seismic restraint and five cycles as a unit,time of stratigraphic units in Palogue are established, and are modified the previous non-uniform stratigraphic correlation. Through research, a braided and meandering stream of sequence stratigraphy and correlation of unit ideas and technology are formed.sedimentary facies distribution and prediction are carried out under the sequence stratigraphic framework constrained integrated information, single well phase, log phase, seismic facies, and the well constrained inversion are combined ability to improve interwell prediction, sedimentary facies mapping of industrialization are completed in time cell,all of these are providing accurate geological model for fluid flow unit and distribution of interbeds.The results are shown that, From below of Samaa II and Yabus formation have a evolution from braided to meandering river, formation of quasi-plains are clear. The five cycles of the spatial distribution within the sedimentary facies, developmental characteristics and evolution of sand body distribution rule are analyzed,also ancient landscape, growth fault, multiple source, climate and other factors controlling reservoir distribution layers are researched. All of the findings provide a scientific basis for depth exploration and development in palogue oil field of 3/7 area of Sudan. |
