Impact of Structural Complexity on Migration Pathways—Basin Modelling Study Based on a Natural Example, Northern Termination of the Moab Fault (USA)

Abstract

Fault architecture and permeability impact the HC migration pathways and consequently the HC volumes trapped in the produced reservoir. In structurally complex zones, a key step to approximate the reservoir volumes is a correct up scaling of the fault geometry and transmissivity. We propose a basin modelling of the impact of coexisting multiple fault orientations on HC migration pathways through time. This workflow starts from a reference scenario built on a natural example. Fieldwork along the northern termination of the Moab fault, (Uinta petroleum province, USA), reveals the coexistence of differentially orientated fault segments on outcropping red sandstones. These Jurassic formations are differentially bleached by paleo-fluid circulation, revealing the HC paleo-migration architecture. The complex structure is rebuilt through time considering the all sedimentary pile from the Permian Paradox Formation and is calibrated in temperature and pressure. In relay and fault termination zones, fault structures are complex and up scaling strategy is critical in order to preserve important migration pathways that are not necessarily located along or through the main fault direction. Numerical scenarios of fault transfer property evolution through time integrating this complexity are set to test i) the source rock location and properties; and ii) the role of the fault architecture and permeability pattern on the observed paleo-reservoir filling. Such a basin modelling allows testing the field hypotheses on HC migration timing and pathways evolution.

AAPG Datapages/Search and Discovery Article #90217 © 2015 International Conference & Exhibition, Melbourne, Australia, September 13-16, 2015