Modeling propellant-based stimulation of a borehole with peridynamics

Journal Article · Mon Feb 27 00:00:00 UTC 2017 · International Journal of Rock Mechanics and Mining Sciences

DOI: https://doi.org/10.1016/j.ijrmms.2017.02.006 · OSTI ID:1356219

Panchadhara, Rohan ^[1]; Gordon, Peter A. ^[1]; Parks, Michael L. ^[2]

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1. ExxonMobil Research and Engineering, Annandale, NJ (United States)
2. Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

A non-local formulation of classical continuum mechanics theory known as peridynamics is used to study fracture initiation and growth from a wellbore penetrating the subsurface within the context of propellant-based stimulation. The principal objectives of this work are to analyze the influence of loading conditions on the resulting fracture pattern, to investigate the effect of in-situ stress anisotropy on fracture propagation, and to assess the suitability of peridynamics for modeling complex fracture formation. In peridynamics, the momentum equation from the classical theory of solid mechanics is replaced by a non-local analogue, which results in an integrodifferential conservation equation. A continuum material is discretized with a set of material points that interact with all other points within a specified distance. Interactions between points are governed by bonds that can deform and break depending on loading conditions. The accumulated breakage of bonds gives rise to a picture of complex growth of fractures that is seen as a key advantage in the peridynamic representation of discontinuities. It is shown that the loading rate significantly influences the number and ex- tent of fractures initiated from a borehole. Results show that low loading rates produce fewer but longer fractures, whereas high loading rates produce numerous shorter fractures around the borehole. The numerical method is able to predict fracture growth patterns over a wide range of loading and stress conditions. Our results also show that fracture growth is attenuated with increasing in-situ confining stress, and, in the case of confining stress anisotropy, fracture extensions are largest in the direction perpendicular to the minimum compressive stress. Since the results are in broad qualitative agreement with experimental and numerical studies found in the literature, suggesting that peridynamics can be a powerful tool in the study of complex fracture network formation.

• Research Organization: Sandia National Laboratories (SNL-NM), Albuquerque, NM (United States)
• Sponsoring Organization: ExxonMobil CRADA; USDOE
• Grant/Contract Number: AC04-94AL85000
• OSTI ID: 1356219
• Report Number(s): SAND--2015-11064J; PII: S1365160917301089
• Journal Information: International Journal of Rock Mechanics and Mining Sciences, Journal Name: International Journal of Rock Mechanics and Mining Sciences Journal Issue: C Vol. 93; ISSN 1365-1609
• Publisher: ElsevierCopyright Statement
• Country of Publication: United States
• Language: English