Source Rock Kinetics – An Often Neglected Variable in Petroleum System Analysis
Philipp P. Kuhn¹, Matthias Keym¹, Olaf Podlaha¹, and Rolando di Primio²
¹Shell Global Solutions International, Rijswijk, The Netherlands
²GFZ German Research Centre for Geosciences, Potsdam, Germany
In basin modeling a great amount of time and effort is invested to reconstruct the evolution of a wider basin area as well as the lithological composition and physical characteristics of the deposited sediments to predict temperatures and pressures in the subsurface. To model the generation of hydrocarbons from the kerogen “standard” kinetic datasets which are thought to be representative of the source rock found in the basin are applied. These kinetics usually stem from published datasets or are those provided with the basin modeling software. However, they may not only be misrepresentative of the actual source rock but they will most likely also neglect the potential variability of the kerogen in terms of its thermal stability and transformation behavior. Incorporating standard source rock kinetics might be a good first approach to identify main kitchen areas and to set up an initial model in the absence of individually measured kinetics. However, a full assessment whether the inaccuracy related to standard kinetics devaluates the effort related to the extensive data gathering and refinement to build and calibrate the model needs to be performed.
When modeling the resources in-place in a conventional setting a change of the generated volume might not have such a high impact. This mainly relates to migration as one of the least constrained parameters, which is therefore a difficult process to predict in the subsurface. On the other hand, for unconventional settings with a less pronounced impact of the ambiguities linked to migration and with production locations more closely related to the areas of hydrocarbons generation, a better knowledge on the volume of the latter is necessary. Important as it is for a gas play, the significance of the correct understanding of the kerogen transformation even increases when dealing with a low permeability oil play. Not only has the onset of the generation of the resources to be modeled correctly for these plays but also the composition of the generated products at the different transformation stages and the potential destruction due to secondary cracking.
AAPG Search and Discovery Article #120098©2013 AAPG Hedberg Conference Petroleum Systems: Modeling the Past, Planning the Future, Nice, France, October 1-5, 2012