Relationships between texture and petrophysical properties of Cambro-Ordovician dolomites from southeastern Missouri
- Univ. of Missouri, Rolla, MO (United States). Dept. of Geology and Geophysics
Dolomite is the host rock for Mississippi Valley-type (MVT) ore deposits concentrated in Southeast Missouri as well as other locations worldwide. Deposition of MVT ores occur when hot basinal brines are circulated through porosity in dolomite aquifers. Additionally, dolomites are important reservoirs for hydrocarbon accumulations and are important ground water aquifers. Two basic textural types of dolomite exist: (1) planar dolomite which is characterized by rhombohedral faceted crystals with straight intercrystalline boundaries, these are formed in shallow and burial diagenetic environments; (2) nonplanar dolomite which is characterized by crystals with irregular intercrystalline boundaries. Cambro-Ordovician dolomite specimens were collected from core and from surface locations throughout Southeast Missouri. Effective porosity was determined using helium porosimetry and permeability measurements were made using a gas permeameter. Total porosity as well as dolomitic texture was determined from thin section analysis. Texture was classified according to the system of Sibley and Gregg (1987) and total porosity was classified according to Choquette and Pray (1970). Porecasts of selected samples were prepared and examined using scanning electron microscopy and the binocular microscope to evaluate pore throat geometry. Preliminary analysis of textural, porosity, and permeability data suggests that effective porosity and permeability can be related to crystal size and crystal boundary relationships. Fine crystalline dolomites tend to have lower porosity and permeability than coarser crystalline dolomites. Nonplanar dolomites have lower porosity and permeability than planar dolomites.
- OSTI ID:
- 7069754
- Report Number(s):
- CONF-9303210--
- Journal Information:
- Geological Society of America, Abstracts with Programs; (United States), Journal Name: Geological Society of America, Abstracts with Programs; (United States) Vol. 25:3; ISSN GAAPBC; ISSN 0016-7592
- Country of Publication:
- United States
- Language:
- English
Similar Records
Effect of texture on petrophysical properties of dolomite: Evidence from the Cambrian-Ordovician of southeastern Missouri
Dolomitization and fluid interaction in the Reelfoot rift, southeastern Missouri: Geochemical and petrologic studies