Four critical issues for successful hydraulic fracturing applications

Abstract

This paper reviews four critical mechanisms for successful applications of hydraulic fracturing that have emerged or grown in importance over the past 2 decades. These critical issues are managing height growth, decreasing near-wellbore tortuosity, predicting and engineering network versus localized growth geometry, and promoting simultaneous growth of multiple hydraulic fractures. Building on the foundation of decades of research relevant to each area but with an emphasis on advances within the past 20 years, the review presents available field evidence, laboratory data, and modeling insights that comprise the current state of knowledge. Fluid viscosity, injection rate, and in situ stresses are shown to appear as controlling parameters across all of these issues. The past contributions and limitations on future developments point to a future in which advances are enabled by a combination of fully coupled 3D simulations, advanced laboratory experiments, vastly expanded characterization capabilities, and order of magnitude improvements in monitoring resolution.

Modeling of Simultaneous Propagation of Multiple Blade-Like Hydraulic Fractures from a Horizontal Well

“…An additional pressure drop is also usually related to the tortuosity of the fracture geometry near the wellbore -see Bunger and Lecampion (2017) for discussions. We use here an accepted relation for such entry friction (Lagrone and Rasmussen 1963;Economides and Nolte 2000).…”

Response to the reviewers

“…The comparison of the fracture trace orientation at the borehole wall observed by acoustic televiewer logging with the orientation of the seismic cloud associated with a given fracture allow assessing fracture rotation, also referred to as tortuosity, in the near field of the borehole (Bunger and Lecampion, 2017). An angular difference of about 30 • is typical for most of our experiments.…”

Propagation of a fluid-driven fracture with fracture length dependent apparent toughness

“…Apart from a possible increase of fracture energy 1 in the field compared to the laboratory scale, such deviations, in particular a larger propagation net pressure (the difference between the fluid pressure and the confining stress) might also be explained by other factors such as the additional frictional losses associated with near well-bore fracture tortuosity [10,11]. In any case, these field observations indicate a higher energy demand for larger scale fractures, and hint to further study of the HF growth in quasi-brittle materials.…”