North Alaska Unconventional Resource Playfairway Mapping: A Hydrocarbon Phase Dependent Composite Risk Segment Approach to Evaluating Multiple Stacked Fairways

Duncan, Edward A. and Bird, Kenneth J.
[email protected]

The petroleum system of the Brookian foreland basin, North Alaska, holds three high quality source rock formations. Based on numerous studies, these formations have generated more than one trillion barrels of oil and hundreds of trillion cubic feet of gas. Discovered conventional reservoir accumulations in this basin contain more than 100 billion barrels of oil in place and 50 trillion cubic feet of gas discovered within the general area of the Prudhoe Barrow Arch. The three regionally extensive source rock formations, Triassic Shublik, Jurassic Kingak and Cretaceous Lower Hue/HRZ, share a common burial history that facilitates delineation of thermal maturity and source quality phase dependent petroleum kitchen fairways.

All three source rock intervals, perhaps individually but certainly collectively, have geological attributes that could contribute toward development of a major, sustainable, unconventional oil and natural gas liquids resource province with globally significant, longer term natural gas development potential. The Shublik Formation, the proven dominant source rock in the basin and an early unconventional reservoir evaluation target, is a regionally extensive, fossiliferous, organically rich, complex facies assemblage of phosphatic and calcareous shales and localized sands. The Kingak and Lower Hue/HRZ are more typical, deep marine, condensed section facies assemblages that include calcareous shales and fine sand/siltstone rich zones.

Recent exploration drilling south of Prudhoe Bay Field targeted and successfully penetrated all three source rocks in two vertical wells with extensive whole core recovered from each of the formations. Integration of whole core derived data with well, outcrop and regional 3-D seismic data will be instrumental for delineating both unconventional and conventional resource play fairways.

Spatially accurate, fairway scale, Composite Risk Segment mapping is critical to multivariate integration of the regionally extensive 2,500 feet thick stratigraphic interval containing the targeted source rocks with varying geochemical and geomechanical characteristics. Analytically derived, phase dependent risk segments for each targeted unit, spatially composited, and collectively integrated will provide a volumetrically driven and evergreen approach toward exploration and exploitation planning for responsible new development of these resources in North Alaska.

AAPG Search and Discovery Article #90162©2013 Pacific Section AAPG, SPE and SEPM Joint Technical Conference, Monterey, California, April 19-25, 2013