# Explorer Programs

This page links to CREWES interactive Java Explorers, Plotters and Calculators. This software is made available to all visitors as examples of CREWES research. Source code is available only to CREWES Sponsors.

You will need to have the Java runtime environment (JRE) installed on your computer in order to use this software. As of Java Version 7 Update 51, you will also need to add https://www.crewes.org to the Java Exception Site List. This has been tested in Windows 10 using Microsoft Internet Explorer, Microsoft Edge and Mozilla Firefox.

## Quick Links

- Zoeppritz Explorer
- Anisotropic Zoeppritz Explorer
- Spherical Zoeppritz Explorer
- Energy Ratio Explorer
- Reflectivity Explorer
- TI Explorer
- HTI Explorer
- VTI Explorer
- Hodogram Explorer
- Fluid Properties Calculator
- Interface Parameter Calculator

## CREWES Zoeppritz Explorers and Plotters

CREWES is pleased to offer Zoeppritz Explorer, a useful web-based applet that enables the user to visually 'explore' Zoeppritz equation solutions with various parameter inputs.

The Zoeppritz Magnitude Plotter and the Zoeppritz Phase Plotter are similar to the Zoeppritz Explorer, but render plots in black and white for the creation of easily publishable figures. They trade reduced functionality for increased control over plotting options.

The Anisotropic Zoeppritz Explorer utility lends insight into the realm of materials displaying vertical transverse isotropy (VTI) and horizontal transverse isotropy (HTI). For VTI media it can display both the exact and linearized P-wave reflection coefficients. For HTI media one can explore the behaviour of the linearized P-wave reflection coefficient and compare it with values for an isotropic earth. It features interactively adjustable anisotropy parameters (γ, δ, and ε) as well as the azimuthal angle of incidence.

The Spherical Zoeppritz Explorer calculates reflectivity from point sources rather than from plane waves.

## CREWES Energy Ratio Explorer and Plotter

The Energy Ratio Explorer calculates the fraction of energy transmitted away from the interface as a function of angle for each mode. This provides a useful perspective complementary to that of the Zoeppritz Explorer.

The Energy Ratio Plotter is similar to the Energy Ratio Explorer, but renders plots in black and white for the creation of easily publishable figures. It trades reduced functionality for increased control over plotting options.

## CREWES Reflectivity Explorer

The Reflectivity Explorer enables the user to view a large number of AVO-related approximations to the P-P reflection coefficient for any combination of earth properties. The results can be displayed as functions of either angle, offset, sine-angle, or sine-squared-angle. These are all displays relevant to AVO.

## CREWES TI, HTI, and VTI Explorers

The TI explorers display reflection coefficients for an interface between two VTI media or between two HTI media. Either or both of the layers may be specified as being isotropic. Both exact and linearized reflection coefficients may be displayed.

The TI Explorer displays the azimuthal dependence of reflection coefficients for an interface between two VTI or two HTI media. Either or both of the layers may be specified as being isotropic.

The HTI Explorer displays the azimuthal dependence of reflection coefficients for an interface between two HTI media. Either or both of the layers may be specified as being isotropic.

The VTI Explorer is similar to the Anisotropic Zoeppritz Explorer except that it is specialized to VTI applications, and is more flexible in how parameters may be specified.

## CREWES Hodogram Explorer

The Hodogram Explorer produces hodogram plots for arbitrary input data, typically copy/pasted from a notepad or spreadsheet program by the user.

## CREWES Fluid Properties Calculator

The Fluid Properties Calculator produces information on pore fluids of interest in petroleum exploration. Gas Phase calculations may be carried either by using mole fraction input and employing the Peng-Robinson equation of state, or by using the gas density ratio as input employing empirical relations described by Batzle and Wang (1992). Viscosity is calculated only by the empirical equation route. Liquid Phase and Brine Phase calculations also employ empirical relations based on Batzle and Wang (1992). The Multi-Phase calculations employ simple volume fraction averaging for the density and Woods relation for the bulk modulus. The velocity is calculated from the density and bulk modulus. The viscosity is not calculated.

## CREWES Interface Parameter Calculator

The Interface Parameter Calculator provides a convenient tool for converting between various representations of elastic interface data. One can readily convert from densities and velocities to ratios and contrasts, for instance, as is commonly done in AVO studies.