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Title: Lower Cretaceous (Neocomian Age) Calvin limestone shelf-margin complex, Natchitoches Parish, Louisiana

Conference · · AAPG Bulletin (American Association of Petroleum Geologists); (USA)
OSTI ID:5967674
 [1];  [2]
  1. ARCO Oil and Gas Co., Lafayette, LA (USA)
  2. ARCO Oil and Gas Co., Plano, TX (USA)

The Calvin Limestone is a Lower Cretaceous (Neocomian age) carbonate shelf margin complex. This carbonate complex is stratigraphically located between the Winn Limestone and the Knowles Limestone (Tithonian age). Regional geologic and seismic correlations show this shelf margin to be stratigraphically equivalent with the Calvin Sandstone, Calvin field, Winn Parish, Louisiana. The potential reservoirs in the Calvin Limestone are identified as lithocodium encrusted coral/stromatoporoid boundstone and as rubbly coral/stromatoporoid grainstones formed in areas of high wave energy associated with the reef growth along the shelf margin. These shelf margin facies are limited in an updip (shelfal) direction, as they grade into a wackestone inner shelf lithofacies. The cores from the ARCO Huffman-McNeely Natchitoches Parish, Louisiana, represent slope (grainstones and packstones), shelf-margin (boundstone and grainstone), and the inner shelf (wackestone) carbonate facies. The Calvin Limestone contains microporosity, resulting from the recrystallization of former Mg-Calcite allochems to subhedral to euhedral microrhombic calcite crystals ranging from 1 to 5 {mu} in size. The predominant recrystallized material is Lithocodium, a problematical green algae. The excellent textural preservation and minimicrite crystal size of the nonporous portions of Lithocodium grains suggest that these grains were originally Mg-Calcite. No originally aragonite allochem or equant calcite cements are now microrhombic calcite. The microporosity associated with the boundstone and grainstone facies is the predominant pore network present in the deeply buried Calvin Limestone (>15,000 ft). This deep occurrence suggests that microporosity associated with microrhombic calcite may have excellent preservation potential with burial.

OSTI ID:
5967674
Report Number(s):
CONF-9010204-; CODEN: AABUD
Journal Information:
AAPG Bulletin (American Association of Petroleum Geologists); (USA), Vol. 74:9; Conference: Gulf Coast Association of Geological Societies and Gulf Coast Section of SEPM (Society of Economics, Paleontologists, and Mineralogist) meeting, Lafayette, LA (USA), 17-19 Oct 1990; ISSN 0149-1423
Country of Publication:
United States
Language:
English