Study of Neogene sedimentary facies in Songtao uplift of Qiongdongnan Basin based on micro resistivity imaging logging images
Sedimentary facies analysis is one of the commonly used methods to reconstruct the paleogeographic environment,predict oil and gas reservoirs,hydrocarbon source rocks,and cap rocks,and serving the exploration and development of oil and gas resources.In this paper,on basis of the detailed interpretation of micro resistivity imaging logging images,combined with data from rock cores,log-ging,conventional logging,and related experiments,and guided by sedimentary theory methods,the lithology,rock sequence combina-tion,and sedimentary structure of the Neogene in the Songtao uplift of Qiongdongnan Basin were identified,and sedimentary facies anal-ysis was conducted using this as a facies marker,a sedimentary facies model for the Neogene in the study area was established.The re-sults show that:①Five types of lithologies,including mudstone,siltstone,fine sandstone,medium sandstone and coarse sandstone,were identified from the high-definition micro resistivity imaging logging images of the Neogene in Qiongdongnan Basin.The lithology is rela-tively complex,with a fine overall grain size and a large particle size span.The vertical lithology exhibits obvious cyclicity.②Based on the combination of different morphological lines in the high-definition micro resistivity imaging logging images of the Neogene in Songtao uplift of Qiongdongnan Basin,five types of bedding(horizontal bedding,wavy bedding,tabular cross bedding,trough cross bedding and massive bedding)were identified in combination with the dip log model,and calcareous nodules and bioturbation structures were also i-dentified.③The Neogene sedimentary environment in Songtao uplift of Qiongdongnan Basin is generally characterized by coastal-shallow sea,semi deep sea,and deep sea sediments,with local intervals developing turbidite deposits.The sedimentary evolution law shows that during the late Oligocene Lingshui Formation sedimentation period,the entire area underwent marine transgression and underwent vari-ous sedimentary processes mainly dominated by coastal deltas.During the early Miocene sedimentary period of Sanya and Meishan For-mations,the sedimentary environment gradually transitioned from coastal sedimentary environment to shallow sea and semi deep sea sed-imentary environment.During the sedimentation period of Huangliu Formation and Yinggehai Formation,the seawater further deepened and semi deep sea and deep sea sediments appeared.At the end of the sedimentation period of the Yinggehai Formation,a slow regres-sion occurred,gradually transforming into semi deep sea sedimentation.
万方数据
维普
