Vertical stress magnitude¶
$$
S_v = \int_0^{z} \rho(z) g {\rm d}z
$$
In offshore areas¶
$$ S_v = \rho_w g z_w + \int_{z_w}^{z} \rho(z) g {\rm d}z $$Rules of thumb¶
- $\rho_w \approx 1 \mbox{g}/\mbox{cm}^3$
- increases at a rate of 10 MPa/km (0.44 psi/ft)
- $\rho_{\mbox{rock}} \approx 2.3 \mbox{g}/\mbox{cm}^3$
- increaes at a rate of 23 MPa/km (1 psi/ft)
Density logs¶
In [2]:
IPython.display.Image("images/density_log.png", width=500, embed=True)
Out[2]:
© Cambridge University Press Zoback, Reservoir Geomechanics (Fig. 1.3, pp. 11)
Density log integration¶
In [3]:
IPython.display.Image("images/density_log_int.png", width=500, embed=True)
Out[3]:
© Cambridge University Press Zoback, Reservoir Geomechanics (Fig. 1.3, pp. 11)
