Clay Volume Module
Objective
The Clay Volume Module allows users to calculate the volume of clay using both single clay (GR, SP, Nphi) and dual clay (Neutron-Density, Sonic-Density, and Neutron-Sonic) indicators.
Key Parameters
For single clay indicator methods, the clean and clay endpoints are user visible when a relevant method is active. For dual clay indicator methods, the Clean1 (matrix), Clean2, and clay endpoints are user visible when a relevant method is active.
- Lithology Presets: Parameter updates default values for other parameters based on selected lithology.
- Use GR: Check to use the vclay from gamma ray method.
- GR Method: Select which vclay from gamma ray method to use.
- GR Clean: GR value for a zero clay interval.
- GR Clay: GR value for a 100% clay interval.
- Use ND: Check to use the vclay from neutron-density method.
- RhoB Clean1: Bulk density value of the matrix.
- RhoB Clean2: Bulk density value of a clean, high-porosity zone.
- Rhob Clay: Bulk density value of clay.
- Nphi Matrix: Neutron value of the matrix.
- Nphi Clean 2: Neutron value of a clean, high-porosity zone.
- Nphi Clay: Neutron value of clay.
- Use NS: Check to use the vclay from neutron-sonic method. Clean and clay parameters become visible after activation.
- Use SD: Check to use the vclay from sonic-density method. Clean and clay parameters become visible after activation.
- Use Nphi: Check to use the vclay from neutron method. Clean and clay parameters become visible after activation.
- Use SP: Check to use the vclay from spontaneous potential method. Clean and clay parameters become visible after activation.
- Final VWCL Method: Select how to combine results when multiple methods are active.
Output Curves
Most important curves shown in bold.
- VWCL: Volume of wet clay.
- VCL_GR: Volume of clay from gamma ray method.
- VCL_SP: Volume of clay from spontaneous potential method.
- VCL_NPHI: Volume of clay from neutron method.
- VCL_ND: Volume of clay from neutron-density method.
- VCL_SD: Volume of clay from sonic-density method.
- VCL_NS: Volume of clay from neutron-sonic method.
CPI Config Reference
The relevant configuration file is 05_vclay.yaml.
Display
- Gamma ray track with GR clean and GR clay parameter lines.
- Depth track.
- Spontaneous potential track with SP clean and SP clay parameter lines.
- Neutron track with Nphi clean and Nphi clay parameter lines.
- Vclay comparison track for GR and dual clay indicator methods.
- Vclay comparison track for single clay indicator methods.
- Final Vclay track.
Associated cross-plots
- Neutron-Density: Set endpoint parameters for neutron-density method.
- Neutron-Sonic: Set endpoint parameters for neutron-sonic method.
- Sonic-Density: Set endpoint parameters for sonic-density method.
Associated maps
- Avg_vwcl: Average clay volume for a zone.
- Vwcl_net_res: Average clay volume in intervals flagged as net reservoir for a zone.
- Vwcl_net_pay: Average clay volume in intervals flagged as net pay for a zone.
Recommendations
- Select a primary method, such as neutron-density and set its endpoints first. Then set the endpoints for subsequent methods to match.
- The Final VWCL Method is set to take the minimum of the active methods by default. Taking the average will result in high calculated clay volumes.
- Endpoints can be set by using parameter lines on log plots, parameter overlays on cross-plots, or by user entry in the CPI Params table.
- If user parameters are not visible, click on the “Advanced >>” link in the CPI Params table.
Tags
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