In Danomics Petrophysics Insights users are guided through a workflow that walks them through a number of modules. These modules are located via a dropdown menu at the top center of the window. The modules are listed in the order in which a user should ideally proceed through a project. However, this order is not strictly enforced and the user can start at any module and can seamlessly move both forward and back through the modules. This help article will focus on the Porosity module.
Porosity Interpretation Module
To access the Porosity Interpretation module use the module selector dropdown menu located in the top middle area of of the screen and select “Porosity Interpretation”.
The Porosity Interpretation module is intended to help users calculate effective and total porosity. There are options for TOC correcting porosity as well as substituting in the sonic porosity in intervals where the badhole flag nulls out density-based methods. Methods include:
- Neutron-Density Porosity
- Density Porosity
- Sonic Porosity
- Pecking-Order Porosity (ND -> Density -> Sonic)
- Grain Density Porosity
- Multi-min Porosity
- Mineral Inversion Porosity
- Mineral Inversion Porosity (strict)
All porosity calculations are truncated to be >0 and less than the Phi_max parameter.
((@neutron_final + (($rhob_clean1-@density_final)/($rhob_clean1-$rho_fluid)))/2)
((@sonic_final - $dt_matrix) / ($dt_water - $dt_matrix) / max(1, $dt_shale/100))
Pecking Order Porosity
The Pecking Order porosity is designed to allow users to calculate a porosity when they have inconsistent data sets with respect to curve availability. The method will use the Neutron-Density method if available, if not it will try to use the density porosity, and if that is unavailable it will try the sonic porosity.
Grain Density Porosity
The gain density porosity uses a density porosity equation with a grain density estimated from a back-calculation of the cross-plot porosity.
The multi-min porosity calculation is derived via a density porosity that uses a grain density established from using the RhoMaa-UMaa cross-plot technique. If using this method users will need to set the mineral endpoints on the RhoMaa-UMaa cross-plot. Note that this requires a photoelectric (PE) curve.
Mineral Inversion Porosity
The porosity via the mineral inversion can be done two ways. The “strict” method uses the sum of the pore-filling fluids (i.e., the non-mineral components) as a direct determination of porosity. The alternative is to use the grain density from the inversion in a density porosity equation.
Porosity Calculation Outputs
|Description||Output Curve Name|
|Pecking Order Porosity||pecking_porosity|
Note that all of the curves will have the TOC correction applied if the TOC correction checkbox is checked.