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

1. Gamma ray track with GR clean and GR clay parameter lines.
2. Depth track.
3. Spontaneous potential track with SP clean and SP clay parameter lines.
4. Neutron track with Nphi clean and Nphi clay parameter lines.
5. Vclay comparison track for GR and dual clay indicator methods.
6. Vclay comparison track for single clay indicator methods.
7. 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.