Objective
The Porosity Interpretation module provides several methods for determining the total and effective porosity.
Key Parameters
The various porosity calculation methods use different parameters that can be set on a zone-by-one basis. Parameter visibility is based on porosity method selection. Parameters set zone-by-zone include:
- Porosity method: Specify the porosity method to be used
- RhoB clean1: Bulk density of matrix; shared with clay volume method (Density porosity method).
- RhoB matrix: Bulk density of matrix visible if Split RhoB Matrix and RhoB clean1 enabled (Density porosity method).
- DT matrix: Compressional sonic value of the matrix (Sonic porosity method).
- DT shale: Compressional sonic value of shale (Sonic porosity method).
- TOC Correction:
Parameters that operate across zones are:
- Rho fluid: Bulk density value of the fluid.
- DT water: Compressional sonic value of the fluid.
- Clay porosity: Shale porosity for total to effective porosity calculation.
- Phi Max: Maximum allowable porosity.
- Kerogen density: Bulk density value of kerogen for TOC correction.
- Nphi Kerogen: Neutron value of kerogen for TOC correction.
- Sphi Kerogen: Compressional sonic value of kerogen for TOC correction.
- Split RhoB Matrix and RhoB Clean1: Allow different RhoB matrix parameters between Clay Volume and Porosity Interpretation modules.
Output Curves
- PHIT: Total porosity from the selected method.
- PHIE: Effective porosity.
- DEN_POROSITY: Total porosity from density porosity method.
- ND_POROSITY: Total porosity from neutron-density method.
- SON_POROSITY: Total porosity from the sonic porosity method.
- MINV_POROSITY: Total porosity from the mineral inversion porosity.
- MINV_POROSITY_STRICT: Total porosity from the sum of the fluids in mineral inversion.
CPI Config Reference
The relevant configuration file is 08_porosity.yaml.
Display
- Gamma ray – SP track.
- Depth track.
- Resistivity track.
- Neutron-density track.
- Sonic track
- Clay volume track.
- Grain density track.
- Total and effective porosity track.
Associated cross-plots
None.
Associated maps
- Avg_phit: Average total porosity for the selected zone.
- Avg_phie: Average effective porosity for the selected zone.
- PhiT_net_res: Average total porosity for the selected zone in intervals flagged as net reservoir.
- PhiE_net_res: Average effective porosity for the selected zone in intervals flagged as net reservoir.
- PhiT_net_res: Average total porosity for the selected zone in intervals flagged as net pay.
- PhiE_net_res: Average effective porosity for the selected zone in intervals flagged as net pay.
Recommendations
- When using the porosity from the mineral inversion remember to select either mineral inversion porosity or mineral inversion porosity (strict) options.
- Make sure to adjust the clay porosity to a value suitable for the reservoir being analyzed.
- Adjust the maximum porosity when working in areas with higher porosity to avoid accidentally restricting values.
