Oil & Gas Geology ›› 2009, Vol. 30 ›› Issue (6): 706-712.doi: 10.11743/ogg20090606

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Physical simulation of hydrocarbon accumulation in low-permeability lithologic reservoirs:an example from the Yanchang Formation in the Upper Triassic of the Ordos Basin

Li Yuanhao1, Liu Jianping2, Liang Yan1, Du Yuguo1, Huang Jinxiu1, Zeng Jianhui3   

  1. 1. Exploration and Development Research Institute of PetroChina Changqing Oilfield Company, Xi'an, Shaanxi 710021, China;
    2. Oil Reservoir Development Institute of PetroChina Changqing Oilfield Company, Xi'an, Shaanxi 710021, China;
    3. Basin and Reservoir Research Center, China University of Petroleum, Beijing 102249, China
  • Received:2009-05-14 Online:2009-12-25 Published:2012-01-16

Abstract:

In the late Triassic Yanchang period,the Ordos Basin was a continental depression basin.The deposits of lake-delta facies are prevalent,and hydrocarbon reservoirs are mainly low-and ultra-low-permeability litholo-gic type.A research into the area reveals that the abnormally high pressure resulted from hydrocarbon generation in the Chang-7 Formation serves as the major dynamic force for the episodic migration of oil toward low-permeability reservoirs.Physical simulation was performed to analyze the process and features of hydrocarbon accumulation in low-permeability reservoirs under different pressures and to compare the characteristics of episodic hydrocarbon accumulation and steady hydrocarbon accumulation under different charging pressures and at different charging direction.The results show that,regardless the direction of hydrocarbon expulsion from source rocks,the higher the pressure in the low-permeability lithology reservoirs is,the higher the hydrocarbon accumulation efficiency and the oil saturation are.

Key words: abnormally high pressure, physical simulation of hydrocarbon migration, low-permeability lithologic reservoir, Yanchang Formation, Ordos Basin

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