--> ABSTRACT: Upper Triassic Shublik Formation of North Alaska — An Eagle Ford Type Shale Reservoir Play?, by Hutton, Eric; Agboada, Donne K.; Whalen, Michael T.; Hanks, Cathy L.; #90142 (2012)

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Upper Triassic Shublik Formation of North Alaska — An Eagle Ford Type Shale Reservoir Play?

Hutton, Eric *1; Agboada, Donne K.1; Whalen, Michael T.1; Hanks, Cathy L.1
(1) Geology, University of Alaska Fairbanks, Fairbanks, AK.

The Triassic Shublik Fm. in northern Alaska is the dominant source rock for Prudhoe Bay, the largest conventional hydrocarbon accumulation in North America, and also an emerging shale play that has been compared to the Cretaceous Eagle Ford shale of South Texas. However, not all shale reservoirs are alike due to variations in mineralogy, organic richness and other petrophysical properties. The Eagle Ford and the Shublik appear to have many analogous attributes, but that similarity must be verified before the production characteristics of the Eagle Ford Shale can be used to predict possible reservoir productivity of the Shulbik Formation.

The Middle to Late Triassic Shublik Fm. was deposited in an upwelling zone on a shallow shelf that deepened to the S-SW. This heterogeneous formation consists of four zones and fifteen different facies including claystones, sandstones, limestones, and phosphatic rocks. The unit is truncated to the N-NE by a lower Cretaceous unconformity and depositionally thins to the S-SW where it transitions into distally equivalent members of the Otuk Fm. Shublik research to date has concentrated on source rock potential, lithofacies, depositional setting, and bio-, chemo-, and sequence stratigraphy.

This project analyzes the resource potential of the Shublik Fm. by combining various data-acquisition and reservoir-characterization techniques (outcrop spectral gamma ray data, basic and advanced openhole logs, core analysis, and geochemistry) to evaluate the petrophysical and geomechanical similarities with the Eagle Ford shale. Documentation of the shale’s petrophysical properties will also allow determination of the rocks’ competence by evaluating Young’s Modulus, Poison’s ratio and Brinell hardness numbers. By comparing the lithostratigraphy, TOC, bed thickness and mechanical stratigraphy of the two plays we can establish an effective development approach and estimate ultimate reservoir potential/production performance. This analysis will help determine potential stimulation criteria and completion methodology to better optimize production potential of the Shublik Formation.  

 

AAPG Search and Discovery Article #90142 © 2012 AAPG Annual Convention and Exhibition, April 22-25, 2012, Long Beach, California