Analysis Feature Of Potential Field And Comprehensive Interpretation Of Basin Basement And Meso Neoproterozoic In Ordos Basin

Ordos Basin is the second largest sedimentary basin in China.Its tectonic and sedimentary evolution has always been the focus of geologists and petroleum geologists.In recent years,with the increasing investment in deep ultra deep geophysical exploration,the Mesoproterozoic strata in Ordos Basin,which are less explored,have become an exploration field worthy of attention.In order to deeply study the stratigraphic structure and structural characteristics of the meso Neoproterozoic in the basin,this paper systematically summarizes the previous research results,based on the characteristics and analysis of gravity and magnetic anomalies,and uses the techniques of boundary identification,interface inversion and forward stripping to carry out the research on the division of basement faults,characteristic zoning,basement top interface undulation,and the extraction of Mesoproterozoic gravity anomalies.The related work and achievements are as follows:The geological and geophysical data of the Ordos Basin,especially the meso Neoproterozoic,are collected,and the gravity and magnetic anomalies collected are routinely processed and summarized.The gravity anomaly shows that the whole basin tends to be high in the East and low in the west,and there is a NE trending cascade belt between the East and the West;The magnetic anomalies are banded in east-west or north-east direction,and the positive and negative anomalies are arranged alternately in the basin,showing the characteristics of magnetic crystalline basement.The inversion of the interface of the basement top is carried out by separating the residual Bouguer gravity anomaly reflecting the basement.The total depth of the interface varies from 1km to 10 km,and it is distributed in the form of uplift depression;According to the abnormal distribution of basement uplift depression and magnetic basement,the basement is divided into six characteristic areas,which shows that the basement of the basin is composed of blocks of different lithology,different ages and different metamorphism.Based on the previous research results of Mesoproterozoic strata in the southern margin of Ordos,constrained by seismic logging data,the gravity anomaly of Mesoproterozoic strata is obtained by using the gravity forward modeling method based on node density model.The anomaly information shows that there are negative anomalies in NE direction near Dingbian,Heshui and Luochuan in the meso Neoproterozoic,which may be related to the influence of NE trending depression trough;The favorable exploration area inferred by predecessors is consistent with the low value belt of gravity anomaly.Based on the study of basement fault,top interface of basement and residual gravity anomaly characteristics of meso Neoproterozoic,the understanding of stratigraphic structure and structural characteristics of basement and meso Neoproterozoic is deepened,which can provide information reference for further study of basin oil and gas generation,migration and accumulation and accumulation.