Title: Finite element simulations of 3D planar hydraulic fracture propagation using a coupled hydro‐mechanical interface element

Abstract

Summary Two‐dimensional hydraulic fracturing simulations using the cohesive zone model (CZM) can be readily found in the literature; however, to our knowledge, verified 3D cohesive zone modeling is not available. We present the development of a 3D fully coupled hydro‐mechanical finite element method (FEM) model (with parallel computation framework) and its application to hydraulic fracturing. A special zero‐thickness interface element based on the CZM is developed for modeling fracture propagation and fluid flow. A local traction‐separation law with strain softening is used to capture tensile cracking. The model is verified by considering penny‐shaped hydraulic fracture and plain strain Kristianovich‑Geertsma‑de Klerk hydraulic fracture (in 3D) in the viscosity‐ and toughness‐dominated regimes. Good agreement between numerical results and analytical solutions has been achieved. The model is used to investigate the influence of rock and fluid properties on hydraulic fracturing. Lower stiffness tip cohesive elements tend to yield a larger elastic deformation around the fracture tips before the tensile strength is reached, generating a larger fracture length and lower fracture pressure compared with higher stiffness elements. It is found that the energy release rate has almost no influence on hydraulic fracturing in the viscosity‐dominated regime because the energy spent in creating new fracturesmore » is too small when compared with the total input energy. For the toughness‐dominated regime, the released energy during fracturing should be accurately captured; relatively large tensile strength should be used in order to match numerical results to the asymptotic analytical solutions. It requires smaller elements when compared with those used in the viscosity‐dominated regime.« less

Authors:

Gao, Qian  ^[1];

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• Search DOE PAGES for ORCID "0000-0002-0864-0446"

Ghassemi, Ahmad  ^[1]

• Search DOE PAGES for author "Ghassemi, Ahmad"
• Search DOE PAGES for ORCID "0000-0002-6199-2109"

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+ Show Author Affiliations

1. Reservoir Geomechanics &, Seismicity Research Group, Mewbourne School of Petroleum and Geological Engineering The University of Oklahoma Norman Oklahoma USA

Publication Date:

Sun Aug 02 00:00:00 EDT 2020

Sponsoring Org.:

USDOE

OSTI Identifier:

1644344

Resource Type:

Publisher's Accepted Manuscript

Journal Name:

International Journal for Numerical and Analytical Methods in Geomechanics

Additional Journal Information:

Journal Name: International Journal for Numerical and Analytical Methods in Geomechanics Journal Volume: 44 Journal Issue: 15; Journal ID: ISSN 0363-9061

Publisher:

Wiley Blackwell (John Wiley & Sons)

Country of Publication:

United Kingdom

Language:

English