Question

How can one perform a geochemical investigation of hydrocarbon source rock in an existing petroleum system?

Answer 1

There are many ways to understand source rocks. Screening is the primary analysis that is easy and gives all the required information. Total Organic Carbon is the first one which can be done by Carlo Erba Elemental Analyser. The next one is Rock-Eval pyrolysis or Elemental analysis (H,O,C). From these analyses, you can get all the necessary information of the source rock. in addition, you can do Gas Chromatography (GC), Gas Chromatography-Mass Spectrometry (GC-MS), pyrolysis-Gas Chromatography-Mass Spectrometry (py-GC-MS) and few other different techniques.

There are different ways of evaluation of a hydrocarbon source rock. It starts with measurement of its TOC value and then goes on to assess C,H and O contents of organic matter present within it to understand type of organic matter i.e whether it is of Type I,II,III or Iv type as per Van Krevelen diagram. Other way to do it by gas chromatography.

Rock-Eval pyrolysis is the easiest and rapid method for evaluation of petroleum systems. Along with the previously mentioned methods , you can also do FTIR spectroscopic analysis also.
Rock-Eval pyrolysis, Elemental analysis (CHNSO) and FTIR are relatively simple and will give you a limited data only. GC-MS and/py-GC-MS analysis will give you a large data set but the analysis and interpretation is time consuming.
Non geochemical methods include visual kerogen analysis-coal petrology, palynofacies and palynology for investigating hydrocarbons