Xinjiang Petroleum Geology ›› 2011, Vol. 32 ›› Issue (4): 409-411.

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Calculation Method of Natural Depletion Oil Recovery for Micro-fractured Low Permeability Reservoirs

ZHANG Xiao-liang, ZHANG Jin-qing   

  1. CNOOC Research Institute, Beijing 100027, China
  • Received:2010-10-25 Online:2011-08-01 Published:2020-08-19

Abstract: The conventional depletion oil recovery calculation method based on Darcy equation has certain limitations to fractured low-permeability reservoirs due to the strong anisotropy caused by the natural micro-fracture and the threshold pressure gradient of the matrix. A new depletion oil recovery calculation method is proposed, which can take both the reservoir anisotropy and the non-Darcy flow in matrix into consideration. The study indicates that the natural depletion oil recovery of fractured low-permeability reservoirs within the ultimate drainage radius is only one third of that calculated with the conventional method. The non-Darcy flow oil production decline and the field application are analyzed to verify the calculation rationality, and the calculation result has a good agreement with that of actual low-permeability reservoir development.

Key words: micro-fracture, low-permeability reservoir, natural depletion oil recovery, threshold pressure gradient

CLC Number: