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Electrical Properties Equations

Browse 32 electrical properties petroleum engineering equations with formulas, inputs, outputs, units, and sources.

Electrical-property calculations support Archie parameters, SP-log electrochemical potentials, resistivity, conductivity, geometric factors, and tool-response checks.

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PetrophysicsElectrical Properties

Apparent Resistivity

R=G_t\frac{\Delta V_{12}}{I}

PetrophysicsElectrical Properties

Archie Cementation Exponent from Formation Factor

m=\frac{\ln(F/a)}{\ln(1/\phi)}

PetrophysicsElectrical Properties

Archie Formation Factor from Porosity

F = \frac{1}{\phi^m}

PetrophysicsElectrical Properties

Archie Resistivity Index from Water Saturation

RI = S_w^{-n}

PetrophysicsElectrical Properties

Archie True Formation Resistivity

R_t = \frac{R_w}{\phi^m S_w^n}

PetrophysicsElectrical Properties

Archie Water Saturation from Formation Factor

S_w = \left(\frac{FR_w}{R_t}\right)^{1/n}

PetrophysicsElectrical Properties

Diffuse-Layer Thickness from Salt Concentration

x_d=3n^{-1/2}

PetrophysicsElectrical Properties

Dual-Water Brine-Saturated Rock Conductivity

C_o=\frac{1}{F_o}\left(C_{wf}+f_{dl}v_QQ_v(C_{wb}-C_{wf})\right)

PetrophysicsElectrical Properties

Effect of Clay on Conductivity

C_o=\frac{C_w}{F}+C_s

PetrophysicsElectrical Properties

Electric Resistance to Radial Current from a Wellbore

R_e=\frac{\ln(r_e/r_w)}{2\pi h\sigma}

PetrophysicsElectrical Properties

Electrical Conductivity from Resistivity

\sigma = \frac{1}{\rho_e}

PetrophysicsElectrical Properties

Electrical Resistivity from Resistance Geometry

R = r \frac{A}{L}

PetrophysicsElectrical Properties

Electrochemical Potential - SP Log

E_c=2t_{Cl}\frac{RT}{F}\ln\left(\frac{a_1}{a_2}\right)

PetrophysicsElectrical Properties

Electrode Array Geometric Coefficient

G_t=4\pi r_1\frac{r_2}{r_2-r_1}

PetrophysicsElectrical Properties

Electrokinetic Potential Across Mud Cake

E_k=xp^y

PetrophysicsElectrical Properties

Formation Factor from Water-Filled Rock Resistivity

F = \frac{R_o}{R_w}

PetrophysicsElectrical Properties

Formation Water Resistivity from Resistivity Ratio Method

R_w=\frac{R_t}{R_{xo}}R_{mf}

PetrophysicsElectrical Properties

Generalized Archie Formation Factor with Lithology Coefficient

F=\frac{a}{\phi^m}

PetrophysicsElectrical Properties

Lateral Device Geometric Coefficient

G_L=4\pi AM\frac{AN}{MN}

PetrophysicsElectrical Properties

Membrane Potential for SP Log

E_m=\frac{RT}{F}\ln\left(\frac{a_1}{a_2}\right)

PetrophysicsElectrical Properties

Non-Ideal Shale Membrane Efficiency from Shale Resistivity

m_{eff}=0.47+0.3R_{sh}

PetrophysicsElectrical Properties

Non-NaCl Static Self Potential from Ion Activities

E_{ssp}=-K\log_{10}\left(\frac{a_{Na}+(a_{Ca}+a_{Mg})^{0.5}}{a_{Nam}+(a_{Cam}+a_{Mgm})^{0.5}}\right)

PetrophysicsElectrical Properties

Normal Sonde Geometric Coefficient

G_N=4\pi AM

PetrophysicsElectrical Properties

Relationship Between SSP and Rw - NaCl Predominant

SSP=-K_{sp}\log_{10}\left(\frac{R_{mfeq}}{R_{weq}}\right)

PetrophysicsElectrical Properties

Resistivity Bed Reflection Coefficient

C_R=\frac{R_1-R_2}{R_1+R_2}

PetrophysicsElectrical Properties

Resistivity Index from True and Water-Filled Resistivity

I=\frac{R_t}{R_o}

PetrophysicsElectrical Properties

Rock Conductivity for Clean Water-Bearing Rocks

C_o=\frac{C_w}{F}

PetrophysicsElectrical Properties

Static Self Potential from NaCl Activities

E_{ssp}=-K\log_{10}\left(\frac{a_w}{a_{mf}}\right)

PetrophysicsElectrical Properties

Static Spontaneous Potential from Equivalent Resistivities

SSP=-K\log_{10}\left(\frac{R_{mfe}}{R_{we}}\right)

PetrophysicsElectrical Properties

Total Rock Conductivity from Water Saturation

C_t=C_wS_w\phi E

PetrophysicsElectrical Properties

Waxman-Smits Clean-Sand Brine-Saturated Rock Conductivity

C_o=\frac{1}{F}\left(C_{cl}+C_w\right)

PetrophysicsElectrical Properties

Wellbore Electric Voltage Generation

V=V_{e,w}-\Delta V_e\frac{\ln(r/r_w)}{\ln(r_e/r_w)}