Geomechanics: stresses on a horizontal borehole

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Determination of the stress state on the wall of a wellbore in an anisotropic formation is a challenging issue in oil and gas industry. This tool provides analytical solutions, with plane strain assumption, of the effective radial and ortho-radial stresses on the wall of a horizontal wellbore which is located in a vertical transversely isotropic porous medium (Jaeger et al.,2009; Suárez-Rivera et al., 2011; Do et al., 2017). The wellbore is subjected at far-field total vertical and horizontal stresses σV and stress σH, respectively, and a pore pressure Ppore while on the borehole wall (that can be permeable or impermeable) a fluid pressure Pmud is applied. The effective stress is calculated from the Biot's theory. For the case of permeable borehole wall, flow around the wellbore is considered in the steady state condition.



References
Jaeger, J. C., Cook, N. G., & Zimmerman, R. (2009). Fundamentals of rock mechanics. John Wiley & Sons.
Suarez-Rivera, R., Deenadayalu, C., Chertov, M., Hartanto, R. N., Gathogo, P., & Kunjir, R. (2011, January). Improving Horizontal Completions on Heterogeneous Tight-Shales. In Canadian Unconventional Resources Conference. Society of Petroleum Engineers.
Do, D. P., Tran, N. H., Hoxha, D., & Dang, H. L. (2017). Assessment of the influence of hydraulic and mechanical anisotropy on the fracture initiation pressure in permeable rocks using a complex potential approach. International Journal of Rock Mechanics and Mining Sciences, 100, 108-123.

Vertical plane of a horizontal borehole.
(left-side) Vertical plane of a horizontal borehole; (right-side) Steady state pore pressure regime (for the case of permeable borehole wall).


Input the farfield in-situ stresses, pore pressure, mud pressure and the anisotropic poroelastic properties, the permeability anisotropy of rock as well as the borehole condition then click the Compute button to run the simulation.


Borehole conditions
(0 for impermeable borehole, 1 for permeable borehole and steady state pressure regime)

Young modulus Ex (MPa)

Young modulus Ey (MPa)

Poisson ratio νxz

Poisson ratio νyx

Shear modulus Gxy (MPa)

Biot's coefficient αx

Biot's coefficient αy

Permeability ratio kx/ky (not necessary for impermeable borehole wall)

Mud pressure Pmud (MPa)

Pore pressure Ppore (MPa)

Farfield horizontal stress σH (MPa)

Farfield vertical stress σV (MPa)

(Note: positive sign convention for compressional stress)







Output data