Investigation of Fracture Height Growth in Multiple-Layered Rock from Lab Test to Field Diagnosis in Unconventional Reservoirs

Bedding, as an important feature of shale oil and gas reservoirs, plays a key role in hydraulic fracture height containment. In this study, large-scale physical model simulation experiments of hydraulic fracturing were performed to study the effects of bedding on the full 3D growth of fracture height, and the field monitoring data of hydraulic fracturing in ten wells of three shale oil and gas blocks in China were summarized and analyzed, in combination with the theoretical analysis. The growth morphologies and main controlling factors of fracture height under different bedding conditions were clarified. Research results show that existence of bedding results in three growth morphologies of fracture height: fracture crossing, fracture arrest (bedding shearing or opening) and fracture deviation. The orthogonal analysis indicates that under the normal tectonic stress condition, the bedding bonding strength is the most crucial factor affecting growth of fracture height. Field practices further demonstrate that the planar distribution of natural fractures and the different mechanical properties between the vertical layers also have tremendous effects upon growth of fracture height. Therefore, the geology-engineering integrated research is expected to provide an important technical support to efficient reservoir stimulation of unconventional reservoirs.