There exists the continental facies marl in the Anding Group of the Middle Jurassic System in Yanan district. In this marl the content of CaO is lower than 30% and the contents of SiO2 and MgO are very high. So, it is usually not used as the cement raw material.
The stratum frame of Yanchang formation in Yan'an area is founded with the sequence-stratigraphy, Chang 6 is anatomised in detail. Sediment system is analyzed, mode of lithology and logging curve responding, sedimentary microfacies and evolvement is established.
This research is focused on Yan'an area of ordos basin, with the object of Upper Triassic Yanchan Formation and the core of Chang 6 reservoir(6th part of Yanchan Formation), based on analyzing the reservoir and oil reservoir from deposition, diagenesis, anisotropism, crack, and influence of deep huge fault inside the basin. The formation, distribution and controlling factor of remaining oil are also discussed.