Use this geological calculation for a transparent first-pass interpretation of measured rock, soil, fluid, well, stratigraphic, isotopic, geophysical, or seismic data under an explicitly selected model.

Overburden gradient

Vertical overburden stress gradient in pascals per metre.

Poisson ratio

Formation Poisson ratio, dimensionless.

Pore gradient

Pore pressure gradient in pascals per metre.

Estimate the fracture pressure gradient with the Eaton (1969) relation FG = Pp + nu/(1-nu) * (Sv - Pp). The tool evaluates the supplied inputs together and returns the named outputs below; it does not infer omitted operating conditions or change the units shown.^[1]

Fracture gradient

Fracture pressure gradient in pascals per metre.

• Geological models are scale-, site-, method-, and calibration-dependent. Heterogeneity, anisotropy, sampling, diagenesis, pressure-temperature history, instrument response, boundary conditions, and empirical-correlation range can dominate the result.
• Use finite inputs in the displayed units and preserve more precision than the final presentation requires. Independently verify safety-critical, financial, compliance, or production decisions.

Compare independent measurements and models, retain units and analytical metadata, propagate uncertainty, and validate interpretations against logs, cores, maps, laboratory data, or field observations.

• Leak Off Test Formation Strength Calculator

  Convert a surface leak-off test pressure into formation strength at the shoe, its fracture gradient and equivalent mud density.

• Hydrostatic Pressure Gradient Brine Calculator

  Compute the hydrostatic pressure gradient of a brine column from its density and local gravity.

• Overburden Gradient Calculator

  Compute the vertical overburden stress gradient Sv = rho_bulk * g from average bulk density.