Modeling of Proppant Transport through Hydraulic Fracture Network

Open Access
Author:
Chang, Oliver Chih-young
Graduate Program:
Petroleum and Natural Gas Engineering
Degree:
Master of Science
Document Type:
Master Thesis
Date of Defense:
October 16, 2013
Committee Members:
  • Yilin Wang, Thesis Advisor
  • Turgay Ertekin, Thesis Advisor
  • Derek Elsworth, Thesis Advisor
Keywords:
  • Proppant
  • Hydraulic fracture network
Abstract:
Hydraulic fracturing is one of the most efficient and effective methods to enable economic oil and gas production in shale gas plays. Hydraulic fracturing creates a fracture network system instead of a planar fracture in real cases. As a matter of fact, proppant transport in the fracture network is extremely important to long-term fracture conductivity. Several models are developed to simulate proppant placement in fracture networks. The models are coupled to a finite-difference based fracture network pressure propagation model developed by Chong Hyun Ahn (Ahn, Wang, 2012) which is able to simulate the propagation of fracture networks. Once the fracture geometry and pressure profile is obtained from the model, the proppant distribution can be generated from the proppant transport models. The four different models are linked to the fracture propagation model with an increasing degree of coupling. With more criteria added on and assumptions taken off, the models are able to generate accurate and trustable proppant distribution in fracture networks. Screen out, one of the most common problem encountered in fields, can also be predicted by these models and engineers can utilize the models to monitor proppant distribution in the network and prevent screen out. Models in this thesis simulate different screen out behaviors and mechanisms, and also identify locations of high screen out potential during the treatment under different scenarios. In general, pressure gradient is a key factor during proppant transport in fracture network. With higher pressure gradient, proppant particles have enough energy to be carried further into the network. As a matter of fact, to maintain a smooth flow field, the pad stage of the treatment is very critical that a larger pad zone ensures higher pressure gradient that the fluid has enough energy to transport proppant with higher velocity and to a further distance. Combined with the pressure fracture propagation model, several controlling factors that affect proppant transport can be obtained from the proppant distribution models. With the models, engineers can design treatments along with the logic and new findings to improve proppant displacement.