›› 2017, Vol. 38 ›› Issue (2): 1-1.doi: 10.7657/XJPG20170215

   

Fractal Percolation Law in Fractured-Vuggy Triple Medium Reservoirs

LIU Huapu, LIU Huiqing, WANG Jing   

  1. (MOE Key Laboratory of Petroleum Engineering, China University of Petroleum, Beijing 102249, China)
  • Online:2019-01-01 Published:1905-07-14

Abstract: Fractured-vuggy triple medium reservoirs are characterized by strong heterogeneity and complex pore structures. In order to describe the complex systems more accurately, fractal theory is introduced to establish a fractal mathematical model for fractured-vuggy triple medium reservoirs. By means of Laplace transformation and Stehfest numerical inversion, the bottom hole pressure is obtained; Matlab programming is used to map pressure curves, classify flowing stages and analyze percolation characteristics and fractal parameter sensitivity; percolation parameters are interpreted to verify the accuracy of the model on the basis of drilling and logging data. The results show that the percolation process of the fractal triple medium fractured-vuggy reservoirs can be divided into 5 stages—wellbore storage at the early stage, channeling from caves to fractures, pseudo radial flow between caves and fractures, channeling among matrix, caves and fractures, and the total radial flow. The fractal coefficient could affect the whole percolation process. The fracture tortuosity increases with the increase of fractal coefficient, which results in the increase of flow resistance, more up-shifting of pressure derivative curves and more upwraping of the curves at the total radial flow stage

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