Van Everdingen-Hurst Aquifer Influx Calculator

Reservoir Geomechanics & Water Drive: Calculate dimensionless time ($t_D$), dimensionless influx ($W_D$), water influx constant ($U$), and cumulative water encroachment ($W_e$).

Aquifer & Reservoir Rock Properties

Aquifer Permeability $k_a$ (mD):

Aquifer Porosity $\phi_a$:

Reservoir Outer Radius $r_R$ (ft):

Aquifer Net Pay $h_a$ (ft):

Fluid Properties & Boundary

Water Viscosity $\mu_w$ (cp):

Total Compressibility $c_t$ (10⁻⁶ psi⁻¹):

Encroachment Angle $\theta$ (°):

Boundary Pressure Drop $\Delta P$ (psi):

Encroachment Duration $t$ (days):

Water Encroachment Performance

Cumulative Water Influx ($W_e$)

-- MMbbl

Average Rate: -- bbl/day

Dimensionless Time ($t_D$)

Dimensionless Influx W_D: --

Aquifer Influx Constant ($U$)

-- bbl/psi

Geometry factor f = --

Diffusivity Constant ($\eta$)

-- ft²/day

Infinite Radial Aquifer

Van Everdingen-Hurst Solution:

• $t_D = \frac{0.006328 k_a t}{\phi_a \mu_w c_t r_R^2}$. Field units: $k$ in mD, $t$ in days, $c_t$ in psi⁻¹, $r_R$ in ft.

• Influx constant: $U = 1.119 \phi_a c_t h_a r_R^2 (\theta / 360)$ bbl/psi. Cumulative influx: $W_e = U \Delta P W_D(t_D)$.

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Van Everdingen-Hurst Aquifer Influx Calculator

Aquifer & Reservoir Rock Properties

Fluid Properties & Boundary

Water Encroachment Performance

Frequently Asked Questions