In Danomics Petrophysics 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 Cutoffs Interpretation module and how to set your petrophysical cutoffs.

Cutoffs Interpretation Module

Danomics petrophysics software lets you quickly set your petrophysical cutoffs.

To access the Cutoff Interpretations module use the module selection dropdown menu and choose “Interpretation Plot”.

The Cutoffs Interpretation module allows the users to calculate flags for Gross Reservoir, Net Reservoir, and Net Pay. A value of 1 means the criteria for the flag is met, and a value of zero means the criteria are not met.

Petrophysical Cutoffs Criteria

Unlike many of the other curves calculated the Gross Res, Net Res, and Net Pay curves evaluate an expression entered by the user. The expression can take as many arguments as the user would like, so it is impossible to cover every permutation. In general, you can use choose from a variety of mathematical operators. Note that curve names are called out with the “@” symbol.

Below are a number of different scenarios.

ExpressionDescription of Expression
@vwcl <= 0.35Is the Vclay less than or equal to 0.35?
@phie >= 0.05Is the Effective Porosity greater than or equal to 0.05?
@vwcl <= 0.35 && @phie >= 0.05Is the Vclay less than or equal to 0.35 AND the Effective Porosity greater than or equal to 0.05?
@phie > 0.05 && @gross_resIs the Effective Porosity greater than 0.05 AND the criteria for Gross Reservoir met?
@gross_res == 1Are Gross Reservoir criteria met?
@gross_resSame as above since Gross Reservoir is a one or zero.
!@badholeIs not flagged as badhole?
!@phie < 0.05Effective Porosity is not less than 0.05?
@vwcl <= 0.35 || @gr_final < 70Is Vclay less than or equal to 0.35 OR Gamma Ray less than 70?
(@vwcl <= 0.35 || @gr_final < 70) && @phie >0.05Is Vclay less than or equal to 0.35 OR Gamma ray less than 70, and Effective Porosity greater than 0.05?
@vwcl <= 0.35 || (@gr_final < 70 && @phie >0.05 )Is Vclay less than or equal to 0.35 OR both Gamma Ray less than 70 AND Effective Porosity > 0.05?
@vwcl*0.5 < 0.35Is Vclay multiplied by 0.5 less than 0.35?

The user should pay special attention to their expressions when using a combination of AND (&&) and OR (||) as it can be difficult to predict the behavior in complex expressions. That is why above those types of expressions are shown using parentheses to group requirements.

A list of the basic operators can be found in this help article.

Petrophysical Cutoffs Output Curves

MethodOutput Curve
Gross Reservoirgross_res
Net Reservoirnet_res
Net Paynet_pay
Categories: HelpPetrophysics