Custom Hydrogen Indices Estimations

François Rosselet
March 21 2017

Hydrogen Index versus Maturity (Ro)

In petroleum geochemistry, the hydrogen index (HI) indicates the source rock potential for hydrocarbons generation (the highest, the best). HI decreases with maturity (temperature, indicated by vitrinite reflectance Ro). Organic matter is divided into 4 types (I to IV). The following pseudo-kinetic points were digitized from raster experimental curves and plot with ggplot.

plot of chunk Digitizing

How to predict HI curves based on original HI and maturity (Ro)?

  • We need to find regression functions to fit each curves (self-start SSLogis non-linear sigmoid functions)

plot of chunk Regression

Defining functions to predict HI from original HI and Ro

  • We need now to compute a function to predict custom pseudo-kinetic curves calculated from the five regressive curves defined before (example: HIoriginal=750=>100% Type I kerogen, HI original = 600 => 50% Type I 50% Type II, etc…). This function will allow to choose continuous HI values from 0 to 1200.

  • We finally need an additional function to get any HI values along the curve we just calculated above, based on continuous maturity (Ro) values

Final Result

Finally we have our small application:

  • A slider to build a custom pseudo-kinetic curve based on original HI
  • A slider to navigate along the curve based on maturity (Ro)

Note that percentage of different kerogens proportions is reported as well

click on the link to test the application https://frosselet.shinyapps.io/data_products_hi_vs_ro/

click on the link to go to the github related repository https://github.com/Frosselet/Data_Products_Peer_Review