Provenance Sediments and Its Exploration Significance—A Case from Member 1 of Qingshuihe Formation of Lower Cretaceous in Junggar Basin

To reveal the main controlling factor of the distribution of depositional system of local provenance and its influence on reservoir formation, the paleogeomorphology of Che-Mo paleo-uplift has been restored through different methods of research based on investigations of the coring, seismic and well-logging data. The results indicate that the Che-Mo paleo-uplift was developed from Middle Jurassic to Early Cretaceous, and the peak of this development was in Late Jurassic. The paleo-uplift provides the local provenance that controls the distribution of the marginal depositional system and the sand bodies surrounding the Che-Mo paleo-uplift. Information from the core, seismic section, stability coefficient of heavy minerals, the provenance direction, and sand-body thickness argues for its existence. In addition, it also gives a reasonable explanation about the generating mechanism of the sand bodies from which the reservoirs have been found in the area controlled by the paleo-uplift. The formation of ancient reservoirs and their distribution were also determined by the appearance and burial of the Che-Mo paleo-uplift. Tectonic movement including two structural tilting periods, the distribution of local provenance sandstone, fault system, and modern structures are the key controlling factors for oil and gas migration and the formation of the secondary reservoirs. We conclude that those areas that had good correlation between local provenance sandstone and modern structures are favorable for the development of lithologic-stratigraphic reservoirs. The paleoslopes of the Che-Mo paleo-uplift are the main target regions for further exploration. The exploration surrounding the local provenance sand bodies had just begun. Guided by this new understanding, the drilling holes, such as Shamen1, Mo17, Xiayan11, and Xiayan12, have brought some breakthrough. The exploration of lithologic-stratigraphic reservoirs in the central part of Junggar basin will enter a new stage of discovering oil and gas reservoirs.