changes.mady.by.user Arthur Aslanyan (Nafta College)
Saved on Nov 22, 2018
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k_a(p) = k_{ai} \cdot \exp [ - c_k \cdot (p_i - p) ]
Yilmaz and Nur
Narrow pressure range below
\displaystyle c_rk_{a}(p) = ck_{riai} \cdot \frac{ \ln \left( \frac{ p_n }{p_{\rm max}} \right) }{ \ln \left( \frac{p_{ni}}{p_{\rm max}} \right) 1-2(1+\gamma)c_{rm} \xi(p)}{1-2(1+\gamma)c_{rm} \xi(p_i)}
p_n = p_{\rm min} + 1.75 \cdot \phi^{0.51} \cdot (p_{\rm max} - p)
p_{ni} \xi(p) = p_{\rm min} + 1.75 \cdot \phi^{0.51} \cdot (p_{\rm max} - p_i)
Dobrynin
Sandstone
Wide pressure range: pmin = 1 MPa < p < pmax = 200 MPa
