Stress parameter analysis in hydraulic fracturing with open fracture pattern

摘要

The open fracture pattern in hydraulic fracturing affects the shape of the pressure-time record and the determination of the pressure parameters in stress analysis. In the slightly open fracture model, the fracture reopening pressure seems to vary sensitively when the length of the open fracture tip is relatively small compared to the borehole diameter. In adopting the governing equation of the open fracture tip model in the stress analysis, the validity of the apparent fracture reopening pressure in pressure-time record is checked and adjusted by an analytical approach based on the relationship between the reopening pressure ratio and the horizontal stress ratio at the test site. By applying this approach to the test section of the slightly open fracture, the adjusted reopening pressure and the adjusted stress are estimated. The adjusted stress has a valid level compared to the trend of the overall stress according to the depth in the test site.