Tectonic Evolution Of The Buried Hills In The Western Slope Of Shulu Sag And Its Petroleum Geological Significance

The Shulu Sag in the Jizhong Depression of Bohai Bay Basin is located in the eastern detachment zone of the Taihang Mountains.The multi-phase tectonic movements result in the diversity and complexity of the reservoir types in the depression.Due to the low quality of the old earthquake data,the lack of effective combination of data processing technology and geological interpretation,the identification of the buried hill surface is controversial;the predecessors based on the old tectonic evolution research accuracy on the west slope.There are many studies on the Tertiary's oil and gas reservoirs,and the formation and evolution of the deep buried hills are not detailed enough.At the same time,the tectonic evolution of the buried hills and its petroleum geological significance lack systematic research.Based on the new three-dimensional continuous earthquake,drilling,logging,logging and analysis and testing,this paper has carried out a new study on the tectonic evolution and petroleum geological significance of the buried hills in the western slope of the Shulu Sag.On the basis of the organic combination of geological thought and processing technology,the fine slope field interpretation,high-pass filtering and low-frequency protection well control and frequency-adding processing technology are used to re-identify the buried hill surface and the inner-slip fault of the west slope;Using the fault activity analysis method to the west The key faults formed by the sloped buried hills are analyzed for each stage of activity.The balance profile technique is combined with the geometry,kinematics and dynamics of the Xi'an sloping hills to analyze its tectonic evolution.Finally,the west slope of the Shulu sag is analyzed.The control effect of the tectonic evolution of buried hills on hydrocarbon accumulation is of reference for future oil and gas exploration.On this basis,the main understanding is as follows:(1)Changed the understanding that the west slope of Shulu Sag is only monoclinic,and the slopes are less developed with faults and traps,and identified new buried hill traps and faults,such as E21,E22 and other buried hills Trap,and NNE buried hill bedrock fault.(2)The Xinhe fault is a large-scale boundary fault that begins to move from the Mesozoic.Its continuous activity while controlling the formation of the depression also controls the formation and evolution of the western slope.(3)Due to the multi-period structural superposition,the tectonic movement is more complicated,and the stratum erosion is quite serious.As a result,a large number of Cambrian-Ordovician strata remained in the western slope of the depression,and a small number of Carboniferous-Permian and Jixian Mumishan Formations were formed,and the main high-quality reservoirs were in the Cambrian-Ordovician strata.(4)The early tectonic movement has a great effect on the formation of buried hill bedrock faults,which provides the necessary conditions for the formation of buried hill structural traps.The north-south extrusion of the Indosinian-Yanshanian period is of great significance for the formation of the nasal structure of the buried hill.(5)The formation and evolution process of the buried hills in the western slope is in good relationship with the hydrocarbon generation and expiration time of the main source rocks of the third member of the Shahejie Formation.The structural characteristics of the westward and eastward dip of the sag make the western slope a low-potential area,and the probability of trapping the buried hills of oil and gas to the slope is large.(6)The western slope as an advantageous oil and gas pointing area,and the formation unconformity formed in multi-stage tectonic evolution provides the possibility of hydrocarbon migration.