The Ordos Basin is a significant oil and gas basin. Region M is located southwest of the Ordos Basin. Its Chang 8₁ sub-member is primarily delta front, with abundant oil, and is the primary exploration and development target series. Deep research into the sedimentary facies of the Chang 8₁ sub-member has implications for oil and gas exploration. The study area is primarily delta facies, which is further subdivided into four microfacies: underwater distributary channel microfacies, underwater distributary channel inter-facies, estuarine bar microfacies, and sheet sand microfacies, based on core observation, logging interpretation results, and other data, combined with previous understanding and regional sedimentary background and other research results. During the Chang8₁ period, the entire area is dominated by multi-phase underwater distributary channel sand that is superimposed vertically and distributed in nearly east-west strips.

Lin Li. Sedimentary Characteristics of Chang 8₁ Sub-Member of Yanchang Formation in M Area of the Ordos Basin. Academic Journal of Environment & Earth Science (2023) Vol. 5 Issue 2: 15-21. https://doi.org/10.25236/AJEE.2023.050203.

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