(92d) Hydraulic Fracture Height Growth – Real

By some reports, hydraulic fracturing accounts for up to 30% of North America’s oil and 90% of its natural gas reserves.  However, until recently, real data on hydraulic fracture growth mechanisms has been limited. 

The first tool used to try to understand hydraulic fracture growth, and still the industry’s favorite predictive tool, was linear elastic fracture modeling.  Additional technologies, including temperature logs, radioactive and chemical tracers, along with mapping technologies such as tiltmeters and microseismic monitoring, have been increasingly utilized in recent years to verify and calibrate frac models by measuring where and how fractures grow.  These technologies, along with mineback studies, core-throughs, laboratory studies, and modeling, are helping to provide a better understanding of fracture growth mechanisms and conditions under which vertical fracture propagation is helped or hindered.

Recently, much public discourse has taken place about fracture growth in unconventional reservoirs and whether fractures could potentially grow all the way back to the surface, creating communication pathways for frac fluids or produced hydrocarbons to pollute groundwater supplies.  This paper will present real fracture growth data mapped during thousands of fracturing treatments in unconventional reservoirs along with aquifer depths in the vicinity of the fractured wells. Additionally, the authors will present an in-depth discussion of fracture growth limiting mechanisms augmented by the mineback tests and other studies which were performed to visually examine hydraulic fractures.  These height growth limiting mechanisms, which are supported by the mapping data, provide insight into why hydraulic fractures can be longer but more vertically constrained than originally modeled.  This information can be used to improve models, optimize fracturing, and provide definitive data for regulators and interest groups.