Well Interference Calculator

Ei-function (line source solution) for pressure interference between wells.

Parameters

Flow Rate, q (STB/d)

Permeability, k (mD)

Net Pay, h (ft)

Viscosity, μ (cp)

FVF, B (rb/STB)

Total c_t (1/psi)

Porosity, φ (fraction)

Distance, r (ft)

Time, t (hours)

ΔP = -(70.6 qBμ/kh) × Ei(-948 φμc_tr² / kt)

Pressure Drop ΔP

Ei Argument (x)

Ei(-x) Value

ΔP vs Time

ΔP vs Distance

How this works

The Ei-function (exponential integral) solution is the line source solution for transient radial flow in a homogeneous infinite-acting reservoir. It gives the pressure change at distance r from a well producing at rate q.

Valid when: t > 100 φμc_tr_w²/k (wellbore storage effects ended). The log approximation is valid when x = 948φμc_tr²/(kt) < 0.01.

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