• Login
    View Item 
    •   Home
    • University of Alaska Fairbanks
    • UAF Graduate School
    • Geosciences
    • View Item
    •   Home
    • University of Alaska Fairbanks
    • UAF Graduate School
    • Geosciences
    • View Item
    JavaScript is disabled for your browser. Some features of this site may not work without it.

    Browse

    All of Scholarworks@UACommunitiesPublication DateAuthorsTitlesSubjectsTypeThis CollectionPublication DateAuthorsTitlesSubjectsType

    My Account

    Login

    First Time Submitters, Register Here

    Register

    Statistics

    Display statistics

    Petrographic and microfacies analysis of the Shublik formation, northern Alaska: implications for an unconventional resource system

    • CSV
    • RefMan
    • EndNote
    • BibTex
    • RefWorks
    Thumbnail
    Name:
    Knox_A_2018.pdf
    Size:
    30.07Mb
    Format:
    PDF
    Download
    Author
    Knox, April Rae
    Chair
    Whalen, Michael
    Committee
    Hanks, Catherine
    Wartes, Marwan
    Keyword
    Petrology
    Alaska
    North Slope
    Facies
    Lithofacies
    Metadata
    Show full item record
    URI
    http://hdl.handle.net/11122/9669
    Abstract
    The North Slope of Alaska includes a world-class conventional petroleum system that has been producing for approximately 40 years. While the regional stratigraphy includes multiple proven source and reservoir rocks, the Middle to Upper Triassic Shublik Formation (Fm.) is the most prolific. The decline in conventional hydrocarbon production on the North Slope and the presence of high quality source rocks inspire the evaluation of the Shublik Fm. as an unconventional petroleum system where oil or gas are produced directly from source rocks. The Shublik Fm. is a heterogeneous calcareous shale and limestone interval that has been interpreted to indicate deposition influenced by marine upwelling. Lithofacies observed in outcrop consist of intervals of non-resistant organic-rich packages that are interbedded with resistant coarsening upward rhythmic depositional successions of phosphatic and carbonate parasequences. The heterogenous characteristics of the microfacies is one of the challenges in the unconventional exploration of the Shublik Fm. Detailed microfacies descriptions, as part of this study, document the complex lithologies and identify patterns in the occurrence of the microfacies. Microfacies descriptions are the building blocks to identify stacking patterns that define the parasequences. The parasequences observed in core, outcrop, and petrographic analysis are calibrated to well logs to map relevant stratigraphic intervals on a regional scale. A targeted interval for the unconventional exploration of the Shublik Fm. is identified using a relative brittleness index. Flat clam and phosphatic parasequences are the primary packages present within the targeted interval. The parasequences are comprised of small-scale brittle and ductile couplets. High resolution pore imaging and mechanical stratigraphy characteristics are documented within the interval. Pore types and networks provide potential storage and migration pathways within unconventional resource systems. Pore types were imaged at a high resolution using scanning electron microscopy. Pore types that are present within the Shublik Fm. include interparticle, intraparticle, porous floccules, moldic, microfracture, and microchannel. The phosphatic limestone facies contains the greatest amount of porosity including interparticle, intraparticle, and moldic within the phosphate nodules and matrix and fractures surrounding phosphate nodules. Microfracture, microchannel, and intraparticle porosity are the primary pore types within the flat clam facies. Mechanical stratigraphy has a direct impact on the success of hydraulic fracturing. The microfacies descriptions identify laminae scale mechanical stratigraphy characteristics which include erosional surfaces, laminations, graded bedding, mineralogical variation, and textural anisotropy and isotropy. A regional correlation of the targeted interval was developed building upon previous work and utilizing sequence stratigraphic models. Significant parasequence surfaces are readily identified in the well log signatures. The challenge of the heterogeneity of the Shublik Fm. is simplified first by identifying a targeted interval consisting of brittle and ductile packages enriched in TOC. Then recognizing the parasequences contained as part of the interval which include significant characteristics pertaining to pore networks and mechanical stratigraphy. Combining methods and results of this study provides an important component to evaluating the Shublik Fm. as a potential unconventional resource system.
    Description
    Thesis (M.S.) University of Alaska Fairbanks, 2018
    Date
    2018-08
    Type
    Thesis
    Collections
    Geosciences

    entitlement

     
    ABOUT US|HELP|BROWSE|ADVANCED SEARCH

    The University of Alaska is an affirmative action/equal opportunity employer, educational institution and provider and prohibits illegal discrimination against any individual.

    Learn more about UA’s notice of nondiscrimination.

    Open Repository is a service operated by 
    Atmire NV
     

    Export search results

    The export option will allow you to export the current search results of the entered query to a file. Different formats are available for download. To export the items, click on the button corresponding with the preferred download format.

    By default, clicking on the export buttons will result in a download of the allowed maximum amount of items.

    To select a subset of the search results, click "Selective Export" button and make a selection of the items you want to export. The amount of items that can be exported at once is similarly restricted as the full export.

    After making a selection, click one of the export format buttons. The amount of items that will be exported is indicated in the bubble next to export format.