Abstract
Fluid injection into rock formations can either produce complex branched hydraulic fractures, create simple planar fractures, or be dominated by porous diffusion. Currently, the optimum injection parameters to create branched fractures are unknown. We conducted repeatable hydraulic fracturing experiments using analog-rock samples with controlled heterogeneity to quantify the fluid parameters that promote fracture branching. A large range of injection rates and fluid viscosities were used to investigate their effects on induced fracture patterns. Paired with a simple analytical model, our results identify the threshold at which fracture transitions from an isolated planar crack to branched cracks when closed natural fractures exist. These results demonstrate that this transition can be controlled by injection rate and fluid viscosity. In relation to the field practices, the present model predicts slickwater and lower viscosity fluid injections promote fracture branching, with the Marcellus shale used as an example.
Original language | English (US) |
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Article number | e2021GL093321 |
Journal | Geophysical Research Letters |
Volume | 48 |
Issue number | 12 |
DOIs | |
State | Published - Jun 2021 |
Funding
The authors appreciate the comments of two anonymous reviewers and the associate editor, which helped us improve the paper substantially. The authors gratefully acknowledge funding support from the U. S. Department of Energy (DOE) Basic Energy Sciences (LANLE3W1). Partial supplementary funding was obtained under NSF Grant CMMI‐202964 to Northwestern University.
ASJC Scopus subject areas
- Geophysics
- General Earth and Planetary Sciences