D.O. Hayba1, David W. Houseknecht1, E.L. Rowan2
(1) U.S. Geological Survey, Reston, VA
(2) U.S. Geological Survey, Menlo Park, CA
ABSTRACT: Challenges in Modeling the Thermal Evolution of a Foreland Arctic Basin - the Impact of Uplift, Erosion, Overpressure, Advection and Permafrost on the Eastern North Slope, Alaska
We simulated the geologic, hydrologic, and thermal evolution of a portion of the eastern North Slope. Our work, which focused on the Canning River section, was in support of the 1998 USGS petroleum assessment of the Arctic National Wildlife Refuge 1002 area. Modeling this Arctic foreland basin is numerically challenging. Some of the problems are common to modeling foreland basins, such as evaluating variable data quality, estimating heat flux at depth, reconstructing the amount of section removed by erosion, and accounting for the thermal effects of past and present geopressure. More unique modeling issues are the development of permafrost and the presence of thermal springs in the Sadlerochit Mountains.
Some of the challenges in modeling the North Slope were due to software limitations. For example, we compensated for the development of permafrost by "depositing" a highly conductive layer and assigning a 0°C upper boundary. Other challenges, such as recognizing and simulating the thermal effects of paleogeopressure, required careful calibration of modeling parameters. Our final model satisfactorily honors available geologic and thermal constraints provided by data from exploration wells, 2-D seismic lines, and outcrop studies near the Canning River section. The model also provides a conceptual framework for assessing the spatial distribution of potential undiscovered petroleum resources. For example, results suggest that oil generated beneath the deformation front followed migration pathways influenced by stratal geometries and buoyancy. Fluid migration was also affected by temporally variable forces that included north-directed advection related to tectonic uplift, and south-directed advection related to geopressure.
AAPG Search and Discovery Article #90906©2001 AAPG Annual Convention, Denver, Colorado