Development of hydraulic fracture network propagation model in shale gas reservoirs: 2d, single-phase and 3d, multi-phase model development, parametric studies, and verification

Open Access
Author:
Ahn, Chong Hyun
Graduate Program:
Energy and Mineral Engineering
Degree:
Doctor of Philosophy
Document Type:
Dissertation
Date of Defense:
March 14, 2016
Committee Members:
  • Yilin Wang, Dissertation Advisor
  • Yilin Wang, Committee Chair
  • Russell Taylor Johns, Committee Member
  • Derek Elsworth, Committee Member
  • Terry Engelder, Committee Member
  • Luis F Ayala H, Committee Member
Keywords:
  • Hydraulic fracture
  • Shale
  • SRV
  • fracture complexity
  • fracture surface area
Abstract:
The most effective method for stimulating shale gas reservoirs is a massive hydraulic fracture treatment. Recent analysis using microseismic technology have shown that complex fracture networks are commonly created in the field as a result of the stimulation of shale wells. The interaction between pre-existing natural fractures and the propagating hydraulic fracture is a critical factor affecting the created 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 research, we first characterized the mechanics of hydraulic fracturing and fluid flow in the shale gas reservoir. Then, a 2D, single-phase numerical model and a 3D, 2-phase coupled model were developed, which integrate dynamic fracture propagation, interactions between hydraulic fractures and pre-existing natural fractures, fracture fluid leakoff, and fluid flow in a petroleum reservoir. By using the developed model, we conducted parametric studies to quantify the effects of treatment rate, treatment size, fracture fluid viscosity, differential horizontal stress, natural fracture spacing, fracture toughness, matrix permeability, and proppant size on the geometry of the hydraulic fracture network. The findings elucidate important trends in hydraulic fracturing of shale reservoirs that are useful in improving the design of treatments for specific reservoir settings.