From Sediments Deposit Modelling to Accumulations Prediction and Risk Evaluation: An Innovative Workflow Integrating Stratigraphic Modelling Outcomes into Basin Models

LAIGLE, Jean-Marie and DARTOIS, Frederic
BEICIP FRANLAB, 232, Avenue Napoléon Bonaparte, P.O. BOX 213, 92502 Rueil-Malmaison, France ([email protected]), ([email protected])

Assessing petroleum systems using deterministic basin modelling techniques is nowadays widely used in exploration. Among many other parameters, facies maps are key input data controlling thoroughly the fluids related outcomes, pressure, hydrocarbon distribution and volumes. Major uncertainties are generally associated to the lithological content of these facies maps.

Indeed, whereas facies distribution is satisfyingly constrained at wells location, seismic interpretation and regional geological knowledge primarily provide qualitative facies distribution as well as rough quantitative estimation of the lithological content.

In this context, the added value of forward stratigraphic models such as the Dionisos software can’t be overlooked. Indeed, since forward stratigraphic models aim at simulating quantitatively the facies repartition and the sedimentary bodies’ architecture at basin scale, they naturally constitute a major trump for feeding basin model with calibrated and process-based simulated facies maps.

The present work aims at combining the above mentioned techniques for assessing the potential accumulations and the associated risk curves in the Colorado basin.

To rigorously account for the impact of lithologies parameters on the simulated HC volumes, a Dionisos study has been conducted over the full sedimentary column, delivering accurate and quantitative facies maps as well as paleo bathymetries maps for the basin model. An innovative steady state algorithm, aiming at computing depositional profiles with respect to the seismic thickness maps, has been used to calibrate the supplies location and volume as well as diffusion coefficient for the forward stratigraphic model.

In order to assess the impact of sedimentary supplies location and timing on sand content and Net to Gross ratio in the prospective areas, the Qubs methodology, based on experimental design and response surface analysis, has been applied.

The resulting density probability functions on facies distribution have been used as entry functions for the evaluation of the impact of facies maps uncertainty on hydrocarbon accumulations volumes and pressure regime.

This works, demonstrating an innovative coupling of stratigraphic and basin model together with relevant sensitivity and risk analysis techniques, gives access to highly reliable results including associated risk curves. This approach provides guidelines for future development of unique quantitative petroleum systems modelling techniques.

 

AAPG Search and Discover Article #90066©2007 AAPG Hedberg Conference, The Hague, The Netherlands