Multiple Décollement Model and Its Petroleum Geological Significance in Kelasu Subsalt Structural Belt,Kuqa Depression
Wang Qinghua
Cheng Xiaogan
Xie Huiwen
Chen Hanlin
Wu Chao
Mo Tao
Abstract：To further investigate the subsalt structure and its spatial variations within the Kelasu structural belt of the Kuqa Depression,we conducted a detailed structural interpretation of the latest high-quality 3D seismic data in this study.The findings reveal the presence of multiple subsalt décollements that significantly control the subsalt structures in the deep areas of the Kelasu structural belt.Specifically,the Jurassic coal-bearing strata emerge as the primary décollement layer beneath the salt layer.Additionally,lower décollement layer within the Triassic strata were observed in the eastern Kelasu structural belt,while they were absent in the western part.The formation of the lower décollement layer is predominantly influenced by the thickness and lithological composition of the Triassic strata,which are in turn controlled by the shape of the basement.Serving as décollement layer,the Jurassic coal-bearing strata facilitate the stratified migration and accumulation of hydrocarbons sourced from the Triassic and Jurassic formations.Consequently,this process has resulted in the development of two distinct hydrocarbon reservoir systems within the deep subsalt layers of the Kuqa Depression:the mid-combination and lower-combination reservoir systems.Notably,the lower-combination reservoir system,primarily composed of the Triassic-Jurassic Yangxia Formation,is structurally stable and is unruptured by deeply situated large-scale faults.This stability may make it conducive to reservoir development that accumulates the Triassic near-source oil and gas,which is the key target for future deep exploration in the Kelasu structural belt.
Keywords：Kelasu structural beltsubsalt deep formationcoal-bearing décollement layermultiple-décollement structural modelstratified transport and hydrocarbon accumulationnear-source oil and gas reservoirpetroleum geology
Publication Date：2025-01-14
Online Publishing Date：2025-08-15(First online date of this platform, not the publication date of the document)
Pages：13( 97-109 )