The In-situ stresses, the layering, rock strength, perforation .. etc
I would highly recommend you reading Valko' two books on fracturing. He is Texas A&M University Professor. Please download: Msc Project Research Gate.pdf in my profile. It discusses many issues with hydraulic fractures that are practical and economic following Valko's references.
Many factors affect the hydraulic fracturing such as :
- The injection rate
- Viscosity of the fracturing fluid
- Young’s modulus
I would like to guide you for reading the paper is titled" Pre-post test data analysis for hydraulically fractured vertical tight gas well-field case study" that deals with Field Example (RH gas field) to analyze parameters of hydraulic fracturing operation.