Relationship between deepwater sandstone and tight oil of the Triassic Yanchang Formation in Ordos Basin
Fu Jinhua1, 2, Deng Xiuqin2, 3, Zhang Xiaolei2, 3, Luo Anxiang2, 3, Nan Junxiang2, 3
1 Changqing Oilfield Company, PetroChina, Xi′an710018, Shaanxi 2 National Engineering Laboratory for Exploration and Development of Low-Permeability Oil & Gas Fields, Xi′an710018, Shaanxi 3 Research Institute of Exploration & Development of Changqing Oilfield Company, PetroChina, Xi′an710018, Shaanxi
Abstract：A large area of deep water sandstone was developed during the depositional period between lower-mid Chang 6 and mid-upper Chang 7 intervals of Yanchang Formation of Triassic in the center of Ordos Basin. The large area sandstone had a great thickness and distributed continuously paralleled to the long axis of the basin. According to the sedimentary textures and structures and contact relationship, deepwater sandstone could be divided into four types, i. e., sandy debrite, slump stone, turbidite and delta front sandstones. On the base of reservoir characteristics of mineralogy and petrology, it was put forward that the sedimentary characteristics of deepwater sandstone, such as fine granularity, high content of plastic particles as mica and chlorite, as well as developing terrigenous matrix of carbonate and illite, were key factors that caused intense compaction and cementation in reservoir. Through analysis of favorable reservoir conditions, it was the important controlling factors for the forming of massive unconventional tight oil that deepwater sandstone locating in the center of oil source rock, and syngenetically interbedding with hydrocarbon source rock.
Fu Jinhua,Deng Xiuqin,Zhang Xiaolei et al. Relationship between deepwater sandstone and tight oil of the Triassic Yanchang Formation in Ordos Basin[J]. JOPC, 2013, 15(5): 624-634.
