Sedimentary Facies Characteristics Of Shanxi Formation To Shihezi Formation From Hengshanbao Area To Hui'anbao Area In The Ordos Basin

In recent years,as foreland basin reservoir exploration potential of the excavation,western margin of ordos basin has received extensive attention of the oil and gas workers,because of its great exploration potential and relatively low degree of prospecting,the region has gradually become the next important area of the oil and gas exploration.In this paper,based on the western margin of ordos basin the overall regional geological background,with the latest sedimentology,sequence stratigraphy,petroleum geology frontier discipline theory as the instruction,widely collected in the study area and the surrounding region field section,drilling,logging and testing,such as basic data,the geological and tectonic evolution in the studied area,stratigraphic features,the types of sedimentary facies and sedimentary facies belt and skeleton sand body distribution characteristics were studied.The study of geological structure shows that the western margin of ordos basin is located at the confluence of several large tectonic units.By Indosinian,Yanshan and Himalayan multiphase tectonic movement influence,such as occurred in the region of strong thrust nappe,and from south to north,forming a series of the eastward subduction of the thrust,in such aspects as regional geological structure,structure,physiognomy showed obvious segmentation.By looking for regional correlation marker layer,the methods of cycle control and the thickness of the reference,fully with reference to the research achievements of predecessors,the Shanxi formation,Shihezi formation set of strata and the internal layer,the Shanxi formation thickness of about 80-150 m,Shihezi formation thickness of about 250-330 m,with reference to lay a foundation for further research of sedimentary facies of strata thickness.Comprehensive field section,drilling core data and logging data,such as sedimentary microfacies analysis,identify the study area of Shanxi formation,Shihezi formation with river,delta and lake for combination development of continental sedimentary system.The deltaic sedimentary system is mainly composed of deltaic plain and deltaic leading edge subfacies sedimentation.River sedimentary system is mainly composed of meandering river subfacies and braided river subfacies.North river sedimentary system developed in the study area,broadly distributed in Su Yukou-Tao Le area,north of Shanxi formation are mainly composed of meandering river deposition,the Shihezi formation mainly braided river sedimentary,meandering river sand dam constitute the skeleton of river sedimentary sand body.Study area south of Shanxi formation are widely developed meandering river delta sedimentary system,Yin Chuan-R5-B1 well area developed delta plain subfacies deposition,Ciyaobao-Majiatan area developed delta front deposition.Shihezi formation sedimentary period,south along the KS1 well-LC1 well in the study area,and braided river delta sedimentary pond area,and sense area to the southeast in the lake district to form the braided river delta front deposition.Shanxi formation and Shihezi formation in the study area mainly lithologic hydrocarbon reservoirs and lithologic-structural reservoir,comprehensive many factors such as hydrocarbon source rocks,and trap types,points out that Majiatan,Huianbao-Dashuikeng is favorable area.