A numerical approach for pressure transient analysis of a vertical well with complex fractures

详细信息    查看全文

• 作者：Yizhao Wan ; Yuewu Liu ; Wenchao Liu ; Guofeng Han ; Congcong Niu
• 刊名：Acta Mechanica Solida Sinica
• 出版年：2016
• 出版时间：August 2016
• 年：2016
• 卷：32
• 期：4
• 页码：640-648
• 全文大小：2,555 KB
• 刊物类别：Engineering
• 刊物主题：Theoretical and Applied Mechanics
  Mechanics, Fluids and Thermodynamics
  Engineering Fluid Dynamics
  Numerical and Computational Methods in Engineering
  Chinese Library of Science
  
• 出版者：The Chinese Society of Theoretical and Applied Mechanics; Institute of Mechanics, Chinese Academy of
• ISSN：1614-3116
• 卷排序：32

文摘

A new well test model for a vertical fractured well is developed based on a discrete-fracture model in which the fractures are discretized as one dimensional (1-D) entities. The model overcomes the weakness of complex meshing, a large number of grids, and instability in conventional stripe-fracture models. Then, the discrete-fracture model is implemented using a hybrid element finite-element method. Triangular elements are used for matrix and line elements for the fractures. The finite element formulation is validated by comparing with the semi-analytical solution of a single vertical fractured well. The accuracy of the approach is shown through several examples with different fracture apertures, fracture conductivity, and fracture amount. Results from the discrete-fracture model agree reasonably well with the stripe-fracture model and the analytic solutions. The advantages of the discrete-fracture model are presented in mesh generation, computational improvement, and abilities to handle complex fractures like wedge-shaped fractures and fractures with branches. Analytical results show that the number of grids in the discrete-fracture model is 10 % less than stripe-fracture model, and computational efficiency increases by about 50 %. The more fractures there are, the more the computational efficiency increases.KeywordsFractured wellDiscrete-fracture modelNumerical well testHybrid finite element methodComplex fracture