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.

rho b

Bulk density measured by the density log in kilograms per cubic meter.

rho ma

Matrix (grain) density in kilograms per cubic meter.

rho f

Pore-fluid density in kilograms per cubic meter.

Density-log porosity phi_D = (rho_ma - rho_b) / (rho_ma - rho_f) from bulk, matrix and pore-fluid densities in kilograms per cubic meter; the standard formation-density porosity relation. 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]

phi D

Density porosity as a fraction of bulk volume.

• Geotechnical correlations and idealized failure models depend on stratigraphy, sampling disturbance, drainage, stress history, groundwater, density, anisotropy, scale, construction sequence, and laboratory or field method. Site-specific design requires investigation and code factors.
• 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.

• Seismic Acoustic Impedance Calculator

  Acoustic impedance Z = rho Vp from P-wave velocity in meters per second and bulk density in kilograms per cubic meter, returned in pascal seconds per meter.

• Gravity Anomaly Bouguer Calculator

  Land Bouguer anomaly in milligal: g_obs - g_ref + 0.3086 h - 2 pi G rho h, with elevation h in meters and reduction density rho in kilograms per cubic meter (default 2670 kg/m^3).

• Seismic Reflection Coefficient Calculator

  Normal-incidence P-wave reflection coefficient R = (Z2 - Z1) / (Z2 + Z1) from layer velocities in meters per second and bulk densities in kilograms per cubic meter, where Z is acoustic impedance.