Fracture initiation characteristics from multiple radial wellbores

Wang T.; Liu Q.; Zhu B.; Tian S.; Li G.; Guo Z. · 54th U.S. Rock Mechanics/Geomechanics Symposium (2020)

Resumen

Radial drilling-fracturing, combining radial drilling with hydraulic fracturing, is a revolutionary technology for efficient development of unconventional resources. At present, fracture initiation mechanism from multiple radial wellbore is not clear, and there is no corresponding parameters optimization method. In this paper, the numerical and experimental study is conducted to investigate fracture initiation characteristics from multiple radial wellbores. Firstly, numerical fracture initiation model is established by finite element method. Based on the model, effects of radial wellbore orientation, number of branches and in-situ stress on fracture initiation pressure and location are analyzed. Then, a series of tri-axial fracturing experiment is conducted to validate numerical model with cement cubes. Results show that in-situ stress, number of branches and radial wellbore orientation (angle between radial wellbore and maximum horizontal in-situ stress direction) are the main controlling factors affecting fracture initiation. When the number of radial wellbore is greater than 3, fracture initiation pressure can be significantly reduced. The key parameter for controlling multi-fracture initiation in multi-branch radial wellbore is the radial wellbore orientation. The results of tri-axial fracturing experiment validate the established fracture initiation model. The research results are expected to provide support for the application of radial drilling-fracturing technology in unconventional resources.