In Danomics Petrophysics Insights 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 TOC Analysis module.

TOC Analysis Module

To access the TOC Analysis module, use the module selector dropdown menu located in the top-middle of the page and select “TOC Analysis”.

The TOC Analysis module allows users to determine the total organic carbon (TOC) present in an interval. There are several methods available to the user. These include:

  1. Modified Passey
  2. Passey Overlay Methods
    • Passey Sonic
    • Passey Density
    • Passey Neutron
  3. Schmoker
  4. Vernik
  5. Faust
  6. RhoB Avg. Methods

The user has the ability to calculate (or not) TOC for each zone and can elect to not calculate TOC in zones where the gamma ray curve is less than the Min GR Shale parameter. All of the passey methods have options to apply a shifter and a scaler to help match core. Faust also has a calibration factor as well.

Methods, Parameters, and Outputs

MethodParametersOutput Curve Name
Final TOC CurveN/Atoc_final
Modified PasseyRwb; Vretoc_mod_passey
Passey SonicResD Baseline; DT Baselinetoc_slogr
Passey Density ResD Baseline; RhoB Baseline toc_dlogr
Passey Neutron ResD Baseline; Nphi Baseline toc_nlogr
SchmokerSchmoker’s A; Schmoker’s Btoc_schmoker
VernikRhoB Baselinetoc_vernik
FaustFmtoc_faust
RhoB Avg.Nonetoc_combined

The Final TOC curve will be composited together on a formation-by-formation basis using the selected methodologies. The curve is truncated to be between zero and one.

Modified Passey

($toc_sf*((log10(@resistivity_final)-log10(@toc_ro)) * 10 ^ (2.297-0.1688*@toc_lom))/100+$toc_so)

where toc_ro is:

$rwno/@phit^2

and where toc_lom is:

(-8.3180734+(53.367852*$vre)-(45.319273*$vre^2)+(13.422786*$vre^3))/
(1+(1.0895416*$vre)-(1.4275785*$vre^2)+(0.54231042*$vre^3))

Passey Sonic

($toc_sf*(@slogr*10^(0.297-0.1688*@toc_lom))+$toc_so)

where slogr is:

log10(@resistivity_final/$toc_resd_base)+0.02 *(@sonic_final - $toc_dt_base)

Passey Density

($toc_sf*(@dlogr*10^(0.297-0.1688*@toc_lom))+$toc_so)

where dlogr is:

log10(@resistivity_final/$toc_resd_base)+2.5 *(@density_final - $toc_den_base)

Passey Neutron

($toc_sf*(@nlogr*10^(0.297-0.1688*@toc_lom))+$toc_so)

where nlogr is:

log10(@resistivity_final/$toc_resd_base)+4.0 *(@neutron_final - $toc_nphi_base)

Schmoker

(($schm_a/@density_final-$schm_b)*.01)

Vernik

0.67*(($dens_kerogen*($toc_den_base - @density_final))/(@density_final*($toc_den_base - $dens_kerogen)))

Faust

($toc_fm * (clamp(((@sonic_final - $dt_matrix) / ($dt_water - $dt_matrix)), 0.0001, $phi_max) - clamp(((@dt_faust - $dt_matrix) / ($dt_water - $dt_matrix)), 0.0001, $phi_max)))

RhoB Avg. Methods

((((-30.784*@density_final+80.902)*0.01) + ((-17.061*@density_final+46.711)*0.01) + ((-30.28*@density_final+79.94)*0.01) + (((518.0-194.0*@density_final-7.0)/7.3)*0.01) + ((-31.1*@density_final+82.50)*0.01) + ((-29.172*@density_final+77.23)*0.01) + (((156.956/@density_final-58.272))*0.01) + ((-23.0*@density_final+62.1)*0.01) +  ((-26.738*@density_final+70.741)*0.01 ) + ((-42.97115+114.1864/@density_final)*0.01) + ((-26.6694+75.36593/@density_final)*0.01) +  ((-14.9*@density_final+41.11)*0.01))/12)