Sediment-Structural Evolution And Hydrocarbon Reservoir Formation Of Langgu And Baxian Sag

Langgu-Baxian Sags located in Jizhong Depression,which is two of paleogene grabans resting and extend nearly north-east ward,and belong to the eastern depression belt and the north of Jizhong Depression.The geological structure of Langgu and Baxian Sag is complexed owing to multistage structural activities.Langgu Sag is uplift type depression and Baxian type is inherited sags.In Paleogene,both the two sags develop multistage lacustrine depositional environment and thousands of metres of source rocks,they are sediment hydrocarbon center of the lake basin.The region have good hydrocarbon generating conditions,very rich in oil and gas resources and exploration prospects.With the continuous improvement of exploration,reservoir conditions superior structural traps has been drilled.At the same time,along with the large-scale 3D seismic coverage and the application of fine structure interpretation based on the workstation platform is applied,exploration of the complex fault block has done a great deal to a considerable degree.Using the new theory,new ideas,new methods to open up a new field of oil gas field,realize exploration of subtle reservoirs,it has become a important direction of next exploration in Langgu-Baxian sags.In this paper,we grasp the premise of overall geology in the study area,through the comprehensive interpretation of seismic data,the study of sedimentary structure characteristics,the use of structural geology,sedimentology,petroleum geology and other discipline theory,we analysised the data of geological,geophysical,core,combined with the previous study of petroleum geology,researched corridor sedimentary tectonic evolution characteristics of Langgu-Baxian sags,analysised the reservoir model,deepen the understanding of the reservoir prediction and reservoiring conditions,and reached the following conclusions:Contrasted the spatial relations between the igneous rock and the fault bump or strata uplift and observed core in Es4,we hold that Baxian sag,Langgu sag,and Raoyang sag is located in the same basin in Es4-Ek.Magma top support action and ramp-flat faulting formed a double role to control Niutuozhen uplift-Hexiwu tectonic belt.Langgu and BaXian and Wuqing is divided into three separate sag.Langgu-Baxian subsags section develop subaqueous fan and delta front sandbody,deep source of ancient store configuration is good,development scale of lithology and lithologic-structural targets within the source.The petroleum system of Hexiwu tectonic belt is of early hydrocarbon accumulation and long migration and collection.Buried hill reservoir is extremely advantageous conditions,and Ek-Es3 in BaXian,Langgu and Wuqing sag has a good oil source condition,which stands between the two rich oil source.