Carboniferous Distribution And Reservoir Characteristics In Junggar Basin

The Carboniferous in the Junggar Basin is a relatively weak layer of research with a low degree of exploration.The degree of Carboniferous research in different tectonic units is inconsistent.The current exploration results are mostly concentrated in the northwestern margin of the basin,the Luliang-Wucaiwan area and the East of the Junggar basin,and it is difficult to form an overall understanding of the distribution of Carboniferous.The Carboniferous mainly develops volcanic reservoirs and glutenite reservoirs.The study of lithologic distribution and reservoir development factors is of great significance for promoting Carboniferous exploration.Through the Carboniferous wells in the basin,2D seismic data,and the combination of gravity data,according to the results of the previous classification of Carboniferous,the regional comparison section of the Carboniferous is established,and the distribution of Carboniferous is determined.The Carboniferous is widely distributed,and the burial depth is characterized by the shallow north area,the deep south area,the shallow east area and the deep west area.The internal faults of the Carboniferous are developed,and most of them are high-angle thrust faults.The Carboniferous is often separated by faults in the section with interlacing distribution.On the plane,the Carboniferous is unevenly distributed in different tectonic units,and the sedimentary thickness has a matching relationship with the structural unit.The uplifting part is often thinner in the Carboniferous system,which is caused by small sedimentary thickness or late weathering and denudation.Based on the study of the distribution characteristics of Carboniferous,combined with the trace element characteristics of Carboniferous volcanic rocks and the structural characteristics of Carboniferous,the Carboniferous prototype basin was restored,and the balance profile technique was used to synthesize the evolution characteristics of the basin.Evolution stages of the basin were divided: the Devonian-Early Carboniferous ocean basin subduction and erosion stage,the Late Carboniferous-Middle Permian extensional rifting stage,the Late Permian-Triassic foreland basin stage,the Jurassic extension-local Foreland stage,Cretaceous-Paleogene stable continental inland depression stage and Paleogene foreland basin stage.Based on the drilling data and the results of the restoration of the Carboniferous prototype basin,the Carboniferous sedimentary filling characteristics were studied.The Early Carboniferous Carboniferous is mainly composed of marine sediments,the northern part of the Late Carboniferous is the marine phase,and the southern part is the continental phase.The Carboniferous in the basin develops lithology such as volcanic rocks,mudstones,glutenite and carbonate rocks,which has various lithologies.Carboniferous volcanic rocks,glutenite and carbonate rocks can be used as reservoirs.The volcanic rocks as the main research object,through the study of petrological characteristics,petrographic facies and physical properties,lithologic facies,weathering crusts and faults are identified as the main controlling factors.The favorable reservoir belt of volcanic rocks and clastic rocks are predicted.