Sediment provenance and facies characteristics of the Lower Cretaceous Qingshuihe Formation in the hinterland of Junggar Basin (NW China) and its exploration implications

The Moxizhuang-Yongjin area is structurally located in the hinterland of Junggar Basin, with Lower Cretaceous Qingshuihe Formation being a prospective petroleum exploration target in recent years. However, its sediment provenance and sedimentary facies characteristics are currently subject to debate. In this study, the provenance of sediments in the NW margin of the Junggar Basin was inferred by analyzing lithological characteristics, composition of reservoir rock clastics, formation dip logging, seismic reflection profiles, conglomerate thickness, and heavy minerals. This conclusion was further supported by reconstructions of the paleostructure and paleogeomorphology. Furthermore, the sedimentological signature, authigenic sediment color, grain size, sedimentary structures, wireline well logging curves, seismic attributes, sand body distribution, and well-tie sections were combined to distinguish two sedimentary systems (delta, and lake). These systems contained distributary channel, mouth bar, lakeshore, shallow lake, and deep-lake microfacies. Together, the study is significant in understanding and identifying favorable sedimentary facies belts and distribution of reservoir sands in the Qingshuihe Formation as well as in prospecting for favorable oil and gas reservoirs.