The Tectonic Characteristics And Hydrocarbon Accumulation Mechanism Of Pre-mesozoic Buried Hill In Chengdao Area

Pre-Mesozoic burial hills in Chengdao area is one of the important exploring layers in Shengli Chengdao Oil Field.The pre-Mesozoic burial hills in the bottom-up successively developed Archaeozoic Metamorphic rocks,the lower Palaeozoic marine carbonate rocks and ancient Palaeozoic paralic combination.The burial hill characterized by having primary sedimentary thickness(Palaezoic),many types of rock,many times of tectonic superposition,complex structures,residual layer and control factors of reservoir,and a variety of traps.Drawing support on the 3D seismics and abundant drilling data,basing on the study of basic geological characters,using analytical tectornics,focused on the research of tectornic geometry,dynamics and kinematics characteristic,pointed out the control action that tectonic movement operated on hydrocarbon accumulation,such as the fracture development,the residual layer,reservoir development,trap formation and hydrocarbon migration etc.The pre-Mesozoic burial hill experienced Indosinian,Yanshanian and Himalayan period of tectonic movement,also effected by huge shear action of Yanlu fault in early and late Yanshan period,forming Tectonic pattern of three rows of buried hills in the plane,forming compression,extension,strike slip and nagative inversion four kinds of structural style in section.The function direction conversion of the tectonic stress,such as regional extension,compression and twisting,not only controls the development and evolution of the fault,but also caused the formation tendency or the transformation of the structure height,which determines the degree of weathering and denude and the difference of the characteristics of residual layer,even more influences the horizontal distribution of the reservior.Tectonic movement decollates and deforms the stable layers,forming fault block,monadnock,fold etc,multiple buried hill trap types.Nagative inversion faults,strike slip faults formed by tectonic movement,combining multi periods of unconformity surface,formed a stereoscopic hydrocarbon transforming systerm.The study definites the characteristics of structure and the controlling action of hydrocarbon accumulation,finds out main controlling factors of hydrocarbon enrichment in burial hill.And was significiant for recent region buried hill exploration,and provides a reference for the exploration of buried hill reservoir in eastern rift basin.