Development stage of Jurassic Che-Mo Paleouplift in the Junggar Basin and its constraints on sedimentary system

This paper is the result of oil and gas exploration engineering. [Objective]Che-Mo Synsedimentary paleouplift in Junggar basin is an important geomorphic unit that affects the structural style and reservoir distribution characteristics of Jurassic. The study of its development process is helpful to understand the basin mountain coupling relationship and the accumulation law of oil and gas reservoirs in Junggar basin. [Methods]Based on the logging data and seismic data of 41 wells in the abdomen of the basin, this paper makes a detailed analysis and isochronous comparison of Jurassic sand body and stratigraphic structure, and focuses on the synergistic evolution between the phased development of Che-Mo paleouplift and the orogenic belt around Junggar basin, especially Bogda mountain, and its influence on the basin boundary and sedimentary pattern. [Results]The evolution of Che-Mo paleouplift can be divided into three stages:initial development stage, rapid uplift stage and post uplift denudation stage. The initial development stage of Early Jurassic Che-Mo paleouplift has no or little influence on the distribution and structural style of Badaowan Formation and Sangonghe formation. The study area is supplied by Zhayier mountain in the northwest and Kelameili mountain in the northeast, mainly forming braided river delta sedimentary system; The Middle Jurassic was the rapid uplift stage of Che-Mo paleouplift. In addition to the source supply of Zhayier mountain in the northwest and Kelameili mountain in the northeast, Bogda mountain also rose out of the water at the same time and began to supply the source, resulting in significant changes in basin boundary, stratigraphic distribution and structural style, resulting in large-area overlap of the first and second members of Xishanyao Formation, loss or denudation of the third members of Xishanyao Formation, The sedimentary system combination of Braided River Delta and beach bar is formed; The uplift of Che-Mo paleouplift in late Middle Jurassic and late Jurassic resulted in the denudation loss of Toutunhe Formation and Qigu formation, forming a regional unconformity with Cretaceous. [Conclusions]The formation and evolution of Che-Mo paleouplift in Jurassic not only affected the sedimentary landform of the basin, but also significantly changed the basin boundary and provenance pattern, and led to significant changes in sedimentary system, stratigraphic structure style and distribution law.