Hydraulic fracturing through 3D printing and lattice modelling

In this thesis, an experimental and numerical study on the hydraulic fracturing propagation is conducted using the 3D printing techniques and the lattice modelling. The first half of the thesis presents the experimental studies. Firstly, the potential of 3D printing on rock mechanics is explored by Polylactic acid (PLA) material, but its plastic property inhibits the direct simulation of rocks. Then, more brittle powder-based gypsum-like 3D printed specimens are successfully fractured by the split Hopkinson pressure bar (SHPB) system for investigating the dynamic crack propagation and coalescence. In addition to the high accuracy and flexibility in specimen preparation, the desired fracture paths captured by the high-speed camera affirm the suitability of the powder-based material on fracturing test. Finally, this material post-processed with cement curing agent was applied in hydraulic fracturing tests. The desirable brittle fracture patterns driven by the fluid pressure were obtained. In the second half of the thesis, numerical studies are conducted by lattice modelling. A fundamental study on the crack propagation by the distinct lattice spring model (DLSM) was carried out. The relationship on the fracture criterion between the DLSM and linear elastic fracture mechanics is investigated for the first time. The work involves the correlation between the stress intensity factor (SIF) and spring deformation, the influence of the particle size on fracture toughness, and the relationship between the micro-spring failure and critical SIF. Following this, a damage-plasticity model was developed and implemented into DLSM to enhance the predictability on dynamic fracturing. The new constitutive model is capable of predicting the initial and peak fracture toughness, crack speed, and crack patterns. Lastly, a hydro-mechanical model by coupling the DLSM and the lattice Boltzmann method (LBM) was proposed to simulate hydraulic fracturing propagation. A direct coupling algorithm is applied with parallelization of both DLSM and LBM. The coupled model is validated through a series of benchmark problems. The hydraulic fracturing results predicted by the model are well matched to the experimental observations, and the model is promising on simulations in complex geological conditions.

Grantor dc:publisher

UNSW, Sydney

Year dc:date

2017

Author dc:creator

• Jiang, Chao

• 3D printing techniques
• Hydraulic fracturing
• Lattice modelling

Statement dc:rights

• open access
• CC BY-NC-ND 3.0
• free_to_read

Licence

• https://purl.org/coar/access_right/c_abf2
• https://creativecommons.org/licenses/by-nc-nd/3.0/au/

Language dc:language

EN

Identifier

https://doi.org/10.26190/unsworks/19913

OAI identifier oai:identifier

oai:unsworks.library.unsw.edu.au:1959.4/58635