Sedimentary facies of Akekule Formation of the Middle of Triassic in the southeast of Tahe

The sedimentary microfacies of coring interval are divided and the sedimentary microfacies of the single well is studied based on the detailed observations and descriptions of core and combined with regional geological setting,logging information and seismic section.The result shows that the Akekule Formation is braid river deltalacustrine deposit system,which mainly developed braid river delta facies,lacustrine facies,sublacustrine fan facies,and can be further divided into six subfacies as well as several microfacies.The braid river delta plain and front subfacies deposition was developed in the depositional stage of Member 1 of Akekule Formation,and the front subfaceies of the braid river delta developed mainly in the depositional stage of Member 3 of Akekule Formation in the north,the inner fan of sublacustrine fan and shallow lake sediments in the center and the middle fan of sublacustrine fan in the south.This paper proposes that there are two depositional models in the study area,one is the braid riverbraid river deltalake depositional model;the other is the braid riverbraid river deltalakesublacustrine fan depositional model.