Open Access

ARTICLE

Numerical Analysis on the Interaction between Two Zipper Frac Wells with Continuum Damage Model

Xinpu Shen¹

1 Halliburton, USA.

Structural Longevity 2013, 9(1), 1-22. https://doi.org/10.3970/sl.2013.009.001

Abstract

Zipper fracturing (‘zipper frac’) is a popular reservoir stimulation method used to develop unconventional resources, particularly for tight sand oil, shale oil, and shale gas. Adequately understanding the influence of neighboring stimulation stages on generating the desired stimulated reservoir volume (SRV) has significant impact on fracturing design. To discover the mechanism of interaction between neighboring stimulation stages, numerical simulation was performed on the stimulation process step-by-step using the coupled hydro-mechanical Finite Element Method. A continuum damage model is used to simulate fracture phenomena created by fluid injection used for reservoir stimulation.
Numerical results presented here include: 1) distribution of the fracture volume shown with a contour of the continuum damage variable resulting from the injection flow; 2) pore pressure distribution corresponding to the end of a given stimulation stage; 3) contours of the horizontal stress components S-x and S-y.
A comparison of the numerical results of SRV indicates that for the zipper frac method, the SRV generated by sequential injection is narrow and significantly less than that generated by simultaneous injection. Numerical results also indicate that due to the changes in geostress field caused by the neighboring injection, the SRV created by stimulation in the central area of the submodel is much larger than that created at the corner locations. Calibration and modeling of the initial damage field also has significant impact on accurately modeling this multi-physics phenomenon and will be the major subject of the next step of this study.

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