西南石油大学学报(自然科学版)

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Transient Pressure Analysis of Inclined Fracture in Tight Gas Reservoirs

Jia Pin1*, Cheng Linsong1, Li Caiyun2, Huang Shijun1, Liu Hongjun1   

  1. 1. College of Petroleum Engineering,China University of Petroleum(Beijing),Changping,Beijing 102249,China
    2. Exploration & Development Research Institue,Changqing Oilfield Company,PetroChina,Xi′ an,Shaanxi 710021,China
  • Online:2015-06-01 Published:2015-06-01

Abstract:

In view of the inclined hydraulic fracture formed by slant well fracturing,the numerical model for fracture flow was
derived based on the discrete fracture segments and the analytical model for reservoir flow was established by combining slant
plane source function and the superposition principle. A semianalytical model for inclined fracture was developed by coupling
the numerical fracture flow model and the analytical reservoir flow model dynamically in this paper. The flow regimes were
defined,the corresponding pressure or derivate analytical equations were derived and the effect of reservoir and fracture parameters
on transient responses was investigated. The results show that there are five flow regimes including fracture/formation
bilinear flow,formation linear flow,early radial flow,pseudo-compound linear flow and later pseudo-radial flow for inclined
fracture in the absence of the effect of wellbore storage. The wellbore afterflow caused by wellbore storage may mask the fracture/
formation bilinear flow. The period of the effect of the inclination angle and permeability anisotropy on transient pressure
is very long,which will last to later pseudo-radial flow. The existence and duration of fracture/formation bilinear flow and
formation linear flow is only determined by dimensionless fracture conductivity. Finally,a field test in fractured directional
well from Suliger Gas Field verified the validity of the model.

Key words: inclined wellbore, inclined fracture, finite conductivity, couple model, transient pressure analysis