The Main Controlling Factors Of Oil And Gas Distribution On Chang 2 In South Of Shanbei Slope

Ordos Basin is rich in abundant oil and gas resources, and it’s the second of Chinese largest oil and gas basins. The study area is located south of Shanbei slope in the Ordos Basin. Chang 2 reservoir group is the main producing formation.. In order to study the main controlling factors of reservoir’s distribution in this area. Under the guidance of theories of sedimentology and petroleum geology, on the basis of abundant data from geology, drilling, logging,well testing, etc. Combined with regional geological setting, the stratigraphic distribution and correlation, structural features, sedimentary microfacies and sandstone distribution, reservoir characteristics, etc of Chang 2 are comprehensive studied in study area. Also, the top of Chang 1 reservoir group palaeogeomorphic was restored by using the the residual thickness method. so that the relationship between reservoir’s distribution and these are analyzed. Finally, the main controlling factors of oil and gas distribution are summarized.Research shows that Chang 2 reservoir group can be divided into 21, 22 and 23. The top structure of Chang 2 reservoir group is the west-dipping monoclinic, and developing with EW nose uplift which is ranked distribution. Chang 2 are delta plain and delta-front facies deposition. Overlapping sands of distributary channel and subaqueous distributary channel are the main reservoirs. The lithology are mainly fine grained feldspar sandstone and lithic feldspar sandstone. Combining reservoir properties, macroscopic characteristics of the reservoir space, microscopic pore structure characteristics, capillary pressure curve characteristics and thickness and lithology of reservoir in the study area, Chang 2 reservoir is divided into class Ⅱ reservoir. Compared with the neighborhood area, Chang 2 reservoir has the characteristics of high moisture content.After comprehensive analysis, the ancient landforms of Chang 2 reservoir have destructive effects. But the relatively high site of ancient landforms, the nose uplift in superface structure of sand body and thick river sand body are the main controlling factors of reservoirs accumulation. Regional cap of Chang 1, mudstone and silty mudstone at the top of each sedimentary cycle inside Chang 2 reservoir group are the good capping conditions.