Study On The Sedimentary Facies And Sand Body Distribution Of The Second Member Of The Tenggeer Formation In The Wengte Area Of Baiyinchagan Sag

The Baiyinchagan sag is located in the western margin of the Erlian Basin.It is a single-breaking sag-like depression formed in the late Mesozoic.The basin has the structural features of the North-south-nan super.The concavity limit can be divided into three major geological units,namely the western depression belt,the eastern depression belt and the Maohu low bulge between the two depressions.The western depression formed earlier and lasted for a long time.It is the main oil-producing area of Baiyinchao.The late formation of the eastern depression is a secondary oil-producing area with a concave limit.The Unter area is located in the southern slope belt of the eastern depression of the Baiyinchagan sag,and is a tertiary structure on the Baiyin-Wengte fault structural belt.The study area is located in the eastern depression of the Baiyinchagan concave limit.The target interval is the second member of the Tenggeer Formation,namely the Tierling Formation of the Tenggeer Formation.The main research contents are sedimentary facies and sand body distribution.There are many sedimentary systems in the southern slope of Baiyinchao,and the source direction is not clear.There are multiple sources and multiple sedimentary systems alternately deposited.The terrain of the source area is steep,the supply of debris is sufficient,the mechanical differentiation is weak during sedimentation,and the mixed lithology such as argillaceous sandstone and sandy mudstone is developed,and effective reservoir identification is difficult.Based on the main problems existing in the study area,based on the results of previous geological research,guided by the theory of sedimentology and well logging,using 3D seismic,drilling core,core analysis,logging and other materials,sedimentary facies and sand Research on the law of body distribution and some new geological understandings.The contrast marks of the second member of the Tenggeer Formation in the Unter area are unclear,and the sedimentary cycle is not obvious.It is easy to divide the stratum by relying on well logging data.This time,using 3D seismic data constraints,the combination of well and seismic methods is used to improve the accuracy of stratigraphic contrast.There are many sedimentary systems in the target interval,and the research confirms the views of the predecessors.However,the study suggests that the sedimentary system of the alluvial fan is only developed at the edge of the basin,and the size of the alluvial fan is small.The fan delta sedimentary system is underdeveloped.The main sedimentary system type is braided river delta,which is characterized by the development of the delta front subfacies.The source direction of various sedimentary systems is different.The source direction of alluvial fan and fan delta sedimentary system comes from the south and southwest.The main sedimentary system is the braided river from the southeast.Aiming at the problem of difficulty in the identification of stratigraphic lithology and effective reservoirs in the study area,this study uses a variety of curve combination methods to identify sand and mudstone,which better solves the problem of reservoir identification.