Modeling Of Hydraulic Fracture Network Propagation In Shale Gas Reservoirs

Open Access
Author:
Ahn, Chong Hyun
Graduate Program:
Energy and Mineral Engineering
Degree:
Master of Science
Document Type:
Master Thesis
Date of Defense:
November 26, 2012
Committee Members:
  • Yilin Wang, Thesis Advisor
  • Derek Elsworth, Thesis Advisor
  • Terry Engelder, Thesis Advisor
  • R Larry Grayson, Thesis Advisor
Keywords:
  • Hydraulic fracture
  • shale gas reservoir
  • fracture network
  • naturally fractured reservoir
Abstract:
The most effective method for stimulating shale gas reservoirs is massive hydraulic fracture treatments. Recent fracture diagnostic technologies such as microseismic technology have shown that complex fracture networks are commonly created in the field. The interaction between pre-existing natural fractures and the propagating hydraulic fracture is a critical factor affecting the complex fracture network. However, many existing numerical models simulate only planar hydraulic fractures without considering the pre-existing fractures in the formation. The shale formations already contain a large number of natural fractures, so an accurate fracture propagation model needs to be developed to optimize the fracturing process. In this paper, we first characterized the interaction between hydraulic and natural fractures. We then developed a new, coupled numerical model that integrates dynamic fracture propagation, reservoir flow simulation, and the interactions between hydraulic fractures and pre-existing natural fractures. By using the developed model, we also conducted parametric studies to quantify the effects of rock toughness, stress anisotropy, and natural fracture spacing on the geometry and conductivities of the hydraulic fracture network. Lastly, we introduced new parmeters Fracture Network Index (FNI) and Width Anistropy (Wani) which may describe the creation of the fracture network due to natural fracture. This new knowledge helps one understand and optimize the stimulation of shale gas reservoirs.