Research Of Sedimentary Facies Models And Seismic Reflection Characteristics In Daerqi Field Of Baiyinchagan Sag

Seismic body contains a lot of geological information,how to better development and utilization,has always been a hotspot and difficult point of geological industry.This paper mainly uses the measuring logging information in this working area to research the sedimentary microfacies.On the basis of dividing the single microfacies,researching the combined characteristics of sedimentary microfacies depositing in the same sedimentary period,and finding the corresponding relationship of sedimentary microfacies and seismic reflection characteristics by researching the feature of seismic reflection in Daerqi field.Daerqi field is located in the north of the southern slope in Baiyinchagan Sag,the mainly developed sedimentary facies is the braided river delta sedimentary facies,the main sedimentary microfacies contain mouth bar,interchannel,sand sheet and underwater braided channel.On the research of seismic reflection characteristics in the work area,we can find that,the shore and shallow lake facies developed in the gentle slope zone of the work area have the feature of medium to strong amplitude and moderate continuous feature,the frequency will have some changes under the fluence of water depth.When the water becomes deep,the environment will shift from shallow lacustrine phase to fairly deep lake-deep lake facies,showing the trend of the amplitude enhancement and the frequency reducing and the increasing continuity.River phase characterized by high amplitude,low in continuous features,which reflects the limited distribution of sand body.Braided river delta front corresponds to a high-frequency,high-amplitude seismic facies.According to the logging data,geological model of the work area is divided into six kinds,While researching the D24 field,we can find that,the amplitude has different feature for different sedimentary microfacies' combination mode,of which,the combination type of mouth bar,interchannel and the combination of mouth bar,interchannel and sheet sand have higher amplitude,so we can conclude that the amplitude value is mainly controlled by the developmental state of sand and mud interstratifications.The frequency spectrum map in the work area mainly develops unimodal,bimodal and multimodal.The unimodal's seismic facies is relatively single,there is no redundant orientational axis which have the obvious amplitude between the two main orientational axis which distribute above and below and extend very far.While the bimodal and multimodal seismic facies develop other orientational axis which has the obvious amplitude.While the amplitude value is larger,there will be a obvious main peak in the frequency spectrum map.