Abstract:

In order to reveal the main control factor of the distribution of depositional system and sandstone as well as its affection for reservoir forming, we have restored the palaeogeomorphology of CheMo paleouplift through a multimethod research based on the investigation of the coring, seismic and well logging data. The results indicate that CheMo paleouplift was developed from the Middle Jurassic to the Early Cretaceous and reached its peak development in the Late Jurassic. Information from the core, seismic section, heavy minerals, and sandbody thickness can also give a reasonable explanation about the origin mechanism of the reservoirs in this area. The distribution of depositional system and sandstone around CheMo paleouplift was controlled by local provenance sediments. The formation of ancient reservoirs was also determined by the appearance of this 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 secondary reservoirs. We concluded that the area showing good correlation between local provenance sandstone and modern structures is favorable for the development of lithologicstratigraphic reservoirs. The paleoslopes of CheMo paleouplift are the main regions for further exploration. This new understanding has brought a breakthrough in the exploration of CheMo paleouplift. Taking Shamen1 Well as an example, the exploration of lithologicstratigraphic reservoirs in the central Junggar basin will enter a new period.

Key words: Junggar Basin; Member 1 of Qingshuihe Formation of Lower Cretaceous; CheMo paleouplift; local provenance; lithologicstratigraphic reservoirs