Petroleum Engineers
Formulas
  1. Home/
  2. Formulas/
  3. Petroleum Engineering Laboratory/
  4. Resistivity index-Archie's law

Resistivity index-Archie's law

Input(s)

RtR_{t}Rt​: True Resistivity (ohm m)

RoR_{o}Ro​: Resistivity of Rock Filled with Water (ohm m)

Output(s)

RI: Resistivity Index (unitless)

Formula(s)

RI=RtRoR I=\frac{R_{t}}{R_{o}}RI=Ro​Rt​​

Reference(s)

Core Laboratories. 2005. Formation Evaluation and Petrophysics, Page: 42.


Related

Absolute viscosity for Saybolt viscosimeter measurements

Clay concentration of drilling mud (methylene blue test)

Contact angle

Correction factor for facial tension (De Nouy ring method)

Drilling mud density (solid content analysis of drilling muds)

Categories

  • Drilling Engineering
  • Enhanced Oil Recovery and Geothermal
  • Facilities and Process Engineering
  • Fluid Flow and Transport Phenomena
  • Geomechanics and Fracturing
  • Petroleum Economics
  • Petroleum Engineering Laboratory
  • Petrophysics
  • Phase Behavior and Thermodynamics
  • Production Engineering
  • Reservoir Engineering
  • Well Test Analysis
View All Formulas →

Navigation

  • Home
  • Formulas

Resources

  • Formula Repository

About

Petroleum engineering formulas and calculations for reservoir engineering, drilling, production, and more.

© 2025 Petroleum Engineers. All rights reserved.