ABSTRACT: Diagenetic Relationships and Reservoir Quality Implications, Brookian Clastic Sequence, National Petroleum Reserve, Alaska

Thomas C. Mowatt, June C. Mowatt

Petrologic and petrophysical investigations of Brookian sandstones and siltstones from a number of wells in the National Petroleum Reserve in Alaska resulted in recognition of features of interest regarding the diagenetic development of these rocks. Several kinds of labile materials are present, and secondary dissolution porosity has been developed to various degrees. Mineralogic, geochemical, and textural characteristics indicate the potential for development of appreciable porosity of this type in equivalent horizons and/or similar materials within northern Alaska.

Known regional geological, geochemical, and geophysical relationships are consistent with this view. Considerations of hydrocarbon resource potential should include concern for these relationships as integral to appreciation of the overall diagenetic evolution of the region.

Heretofore, the potential for the occurrence of significant reservoir rocks in these horizons has been considered to be rather low, based on primary petrologic characteristics. However, this should be reappraised in light of increased knowledge and understanding of the principles and realities regarding diagenetic events, inorganic and organic, including secondary porosity development, clay mineral relationships, and maturation of organic material.

AAPG Search and Discovery Article #90097©1990 Fifth Circum-Pacific Energy and Mineral Resources Conference, Honolulu, Hawaii, July 29-August 3, 1990