Analysis Of Depositional System Of Silurian Kalpintag Formation In Northern Tarim Basin

The northern part of the Tarim Basin is a ridge,it's structurally located in the Shaya uplift zone in the Tarim Basin,between the Luntai raised,Yingmaili low rise and Shuntuogol low uplift band.This paper aims at the target of the Kalpintag Formation of paleozoic Silurian.Firstly,under the guidance of theory and methods such as sequence stratigraphy,sedimentology,and seismic sedimentology,through the full absorption of pre-digestion research results and regional geological background data,using drilling core,logging data,seismic data,etc to start a comprehensive analysis of the combination of rock facies and rock facies in coring wells.Secondly,analysis single well sedimentary facies and overlay style,combined sequence interface features,to identify and determine the stratigraphy of different strata and establishing a sequence stratigraphic framework.Thirdly,conduct sedimentary facies to well comparisons in sequence stratigraphic framework.Lastly,auxiliary compilation of the distribution of sandstones in different sequence units.This dissertation focuses on the deposition system of Kalpintag Formation in the northern Tarim Basin,the following achievements and understandings have been obtained through the Institute:?1?In the Kalpintag Formation,it was identified that the mudstone facies,the sandstone facies,and the siltstone are equal to 20 types of rock facies and 6 types of rock facies combinations.It can be combined into subphases or microfacies,such as mixing floor,sand flat,undercut waterway,tidal channel,tidal sand dam,shelf shed mud and beach bar.And three kinds of sedimentary facies:tidal flat facies,coastal facies,and shallow sea shelf facies;?2?Based on the identification of sedimentary facies in a single well,combining the seismic reflection interface of the seismic section,logging curve characteristics and combinations,and stratigraphic overlay patterns,two three-level sequences of S₁SQ1?equivalent to the lower section?and S₁SQ2?equivalent to the middle-upper section?are defined in the study area Kalpintag Formation;?3?Contrast ratio deposition within the stratigraphic framework through an isochronal sequence,and analyze the seismic reflection characteristics of different sedimentary subfacies,the horizontal distribution of sandstone thickness and percentage of sandstone in different sequence stratigraphy,to define the distribution and sedimentary evolution of each sequence sedimentary system.Formation of the Silurian Kalpintag Formation sedimentary nodel in the northern Tarim Basin;?4?It is predicted that the favorable phase zone of the Kalpintag Formation in the study area is mainly Tuopu area and S112-2 well area,including underwater channel?tideway and foreshore-on shoreface sand belt.