Objectives
The Cutoffs Interpretation module allows users to flag intervals based on specified criteria. This is typically used to flag intervals as gross reservoir, net reservoir, and net pay based on reservoir properties.
Key Parameters
Cutoffs for gross reservoir, net reservoir, and net pay can be set by the parameter boxes. These are labelled as such.
- Gross Res: Gross reservoir criteria entry.
- Net Res: Net reservoir criteria entry.
- Net Pay: Net pay criteria entry.
Criteria can be defined using basic operators. These include:
| Operator | Description |
| < | Less than |
| > | Greater than |
| <= | Less than or equal to |
| >= | Greater than or equal to |
| == | Exactly equal to |
| ! | “Not” operator |
| && | “And” to combine criteria |
| || | “Or” to combine criteria |
Examples include:
| Example | Description |
| @vwcl <= 0.30 && !@badhole | Vwcl less than or equal to 0.30 AND not flagged as badhole |
| @phit > 0.05 && @gross_res | PhiT greater than 0.05 AND meets gross_res not equal to zero |
| (@sw <= 0.65|| @resd_final > 10) && @net_res | First, Sw less than or equal to 0.65 OR resd greater than 10 AND second, net_res not equal to zero |
Parameters that operate across the well include:
- Use Min H: Specify if a minimum thickness should be used.
- Min Height: Specify the minimum thickness that should be used.
- Map partial zones: Specify if zones with null values be included in summations.
- Limit mapping by data completeness: Specify If mapping should occur only if a certain threshold of data coverage is met.
- Data completeness: Fraction of interval to be covered by data.
- Required curves: Curves that should be considered for data completeness.
Output Curves
- GROSS_RES: Gross reservoir flag.
- NET_RES: Net reservoir flag.
- NET_PAY: Net pay flag.
CPI Config Reference
The relevant configuration file is 10_interpretation.yaml.
Display
- Gamma ray – SP track.
- Depth track.
- Resistivity track.
- Neutron-density track.
- Clay volume results track.
- Porosity results track.
- Water saturation results track.
- Gross reservoir track.
- Net reservoir track.
- Net pay track.
Associate cross-plots
None.
Associated maps
- Gross_res_summary: Summation of gross reservoir thickness for a zone.
- Net_res_summary: Summation of net reservoir thickness for a zone.
- Net_pay_summary: Summation of net pay thickness for a zone.
Recommendations
- When combining criteria with the “OR” operator use parentheses for clarity. For example, how should:
@vwcl < 0.30 || @gr_final < 50 && @phit >= 0.05 || @rhob_final < 2.6
be interpreted? Is it more clear when stated as:
(@vwcl < 0.30 || @gr_final < 50) && (@phit >= 0.05 || @rhob_final < 2.6) - When using the Map partial zones parameter, consider pairing it with a data completeness requirement to avoid mapping zones that may only have a few samples available.
