| The research process of the doctoral dissertation was mainly guided by structural geology,sequence stratigraphy,sedimentology and poll-forming dynamic.The main achievements can be divided into 5 aspects: 1.the vertical and lateral features of faults in Nanpu Sag were summarized;2.surfaces identification,types of slope-breaks and internal architecture of each third-order sequences were identified;3.the types of sedimentary facies and lateral distribution of different depositional systems in different sequences were summarized;4.the spatial-temporal evolution process,internal architecture,main controlling factors,and development models of fans in para-sequence sets were summarized;5.beneficial reservoir belts were predicted based on the differences of reservoir qualities in different sub-facies and different types of fans.Seven types of faults were identified based on their trendings and vertical styles on seismic profile,five third-order sequences are identified: SQEs1,SQEd3 x,SQEd3s,SQEd2,and SQEd1.Five kinds of slope-breaks were figured out in different tectonic belts and sequences: flexure and multi-faults flexure slope-breaks in southern sag,three kinds of structural slope-breaks in northern sag.Five kinds of sedimentary faices were indentified: braided-river delta,fan delta,turbidite fan,lacustrine deposits,and volcanics,comprising 12 kinds of sub-facies and 39 kinds of micro-facies,and the research was conducted mainly based on the observation of lithology and sedimentary structures on cores.Six kinds of sediment supplies were figured out based on the combined features of heavy minerals and light minerals.The spatial-temporal evolution of depositional systems in the target sequences were figured out based on well curves,seismic properties,thickness and percentage of sandstone.Fan deltas were mainly developed in northern and eastern sag,and braided-river deltas were developed in southern sag.Turbidite fans were mainly distributed in the far-end of fan deltas,and the volcanics were developed in the southwestern sag.The deltas in the younger sequences were developed in a larger scale than the ones in older sequences.The para-sequence framework was built in Gaoliu and No.4 tectonic belts,and 20 para-sequence sets were identified.The temporal and lateral evolution of fans were figured out in these para-sequences.The fans were divided into 4 styles based on their external shapes and internal architectures.The triggered mechanism for the formation of different kinds of fans were discussed,which were mainly related to the intensity of faulting and sedimentation rate.Six kinds of development model were figured out based on the research of fans in different para-sequence sets.The reservoir qualities were studied in different kinds of fans,and the differences between different kinds of fans are summarized.The reservoir qualities in subaqueous channels and mouth bar deposits are better than that in delta plain.The reservoir qualities in fans that belong to style 2 and 4 are better than the other two styles.PS1,PS4,PS5,PS8,and PS12 possess the largest predicted favorable area,which can be the target strata for exploration in this area.The predicted amount of para-sequences which possess favorable reservoir in Gaoliu tectonic belt is more than that in No.4 tectonic belt.The elaborated research for the evolution process of fans under the para-sequence framework and the study of reservoir qualities in different kinds of fans in Gaoliu and No.4 tectonic belts provided an important basis for the further exploration in this area.The techniques for fans identification and the research process involving tectonic,thirdorder sequence,para-sequence sets,reservoir qualities,and prediction of beneficial reservoir belts may provide a reference for the research in continental rift lacustrine basins. |
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