Free Subsurface Toolbox

Brine, gas and oil density and bulk modulus at reservoir conditions.

Replace the pore fluid and see the change in Vp, Vs, density and impedance.

Monte Carlo Gassmann returning the probability that hydrocarbon and brine cases can be distinguished.

Estimate shear velocity from P-wave velocity using Castagna, Greenberg-Castagna, and other empirical relationships.

Overlay well or inversion points on a Vp/Vs vs acoustic impedance template.

Two-layer reflectivity against angle, with the AVO class and the intercept-gradient position.

Tuning thickness, the amplitude tuning curve and a wedge model for a chosen wavelet.

Minimum detectable net pay thickness from seismic tuning analysis.

Shows whether a hydrocarbon reservoir would stand out from background or stay hidden.

A structured record of which published DHI characteristics are observed, absent or untested.

Shows why small amounts of gas (5-10%) create strong seismic anomalies.

Calculate EEI for optimal fluid or lithology separation.

Vertical and lateral resolution at target depth.

The incidence angle that acquired offsets reach at target, and whether that is enough for the AVO class expected.

Quality-check NMO velocities from velocity analysis. Identify inversions, picking errors, and unrealistic velocities using Dix and gradient checks.

Work out the polarity convention and approximate phase of a dataset from a known reflector.

Interactive diagnostic workflow to identify causes of poor seismic image quality and recommend processing remedies.

Convert time picks to depth with three velocity models and show how far the answers differ.

Monte Carlo simulation for probabilistic reserves with P10/P50/P90 distributions.

Calculate GRV, pore volume, STOIIP/GIIP with Monte Carlo uncertainty (P10/P50/P90).

Estimate gas column height from velocity anomaly using Gassmann fluid substitution and Wood's equation.

Probabilistic reserves (P10/P50/P90), geological risk, EMV decision tree, and Monte Carlo simulation.

Calculate net pay from well logs with sensitivity analysis showing how cut-offs affect reservoir pay determination.

Identify carbonate pore type (interparticle, moldic, vuggy, fractured) from log signatures using Lucia classification.

Log evidence for fractures, and whether the seismic survey could detect them.

Flags intervals likely to be ash, tuff or igneous rock, and shows how a thin ash bed looks on seismic.

Pore pressure prediction using Eaton's method from sonic or resistivity data.

A hazard register for a proposed well location, built from a guided checklist.

A simple directional plan from surface to target.

One page that combines formation tops with depth uncertainty, the pressure window and the hazard register.

Calculate NRMS and assess 4D seismic repeatability for time-lapse monitoring.

Gas depletion 4D model coupling Batzle-Wang EOS, Gassmann substitution, and stress-sensitive rock frame to decompose instant fluid vs. delayed frame responses.

Gas in place from p/z, and a production forecast from decline analysis.

Static storage capacity of a saline formation or depleted reservoir.

Calculate shale volume using Linear and Larionov methods from gamma ray logs.

Calculate porosity from bulk density log measurements.

Calculate water saturation using Archie's equation from resistivity logs.

Calculate formation water resistivity from spontaneous potential (SP) log deflection.

Identify lithology from density-neutron, Vp-Vs, and M-N crossplots.

Estimate missing well logs using empirical correlations (Gardner, Castagna, etc.).

Calculate interval velocity and depth from RMS velocity picks using the Dix equation.

Calculate fracture gradient using Matthews-Kelly, Eaton, and Hubbert-Willis methods.

Calculate safe mud weight window between pore pressure and fracture gradient.

Build comprehensive one-page well prognosis with formation tops, pressure window, casing design, and hazard analysis.

Calculate optimal well spacing for field development based on drainage radius and economics.