Predicting the permeability of unconsolidated sediments from grain size measurements
- Mobil Exploration and Production Technical Center, Dallas, TX (United States)
- Mobil Global Interpretation Support, New Orleans, LA (United States)
- Centenary College, Shreveport, LA (United States)
Percussion sidewall core samples are frequently taken in poorly consolidated formations, but generally have been of little use in determining formation permeability. Usually, the permeability reported for sidewall samples is based on a porosity correlation. Such correlations are not usable in formations such as the offshore Louisiana, deepwater Pliocene-Pleistocene sand we studied. Almost all of the slightly laminated samples in our study had porosities of 35[plus minus]2 porosity units, but the permeability of these samples ranged from less than 100 md to over 1 d. However, we observed a good correlation between permeability and laser diffraction particle size. If the laser diffraction particle size measurements are made on unfractured grains from sidewall samples, permeability could be predicted using a correlation developed on equivalent conventional cores. Geologists have known for about a century that the permeability of unconsolidated sand is a function of grain size. In this study, the air permeabilities of 1.5-in.-diameter, lead-sleeved samples cut from conventional core were measured at 2850 psi. Prior to mounting the samples in lead sleeves, the laminations in the plug samples was described. Most samples were described as having either slight laminations or variable laminations with one or more laminations greater than 5 mm thick. Laser particle-size measurements were obtained on samples with slight laminations and on the sand layers in laminated samples. A good correlation was obtained between mean grain size determined by laser diffraction and permeability. Sonic sieve particle-size measurements also were obtained on some of the samples. For samples with a mean grain size greater than 90 [mu]m, the sonic sieve and laser diffraction analyses gave approximately the same results. For finer grained samples with permeabilities ranging from 85 to 700 md, the sonic sieve analyses did not provide grain-size resolution accurately enough to predict permeability.
- OSTI ID:
- 6849283
- Report Number(s):
- CONF-9310237--
- Journal Information:
- AAPG Bulletin (American Association of Petroleum Geologists); (United States), Journal Name: AAPG Bulletin (American Association of Petroleum Geologists); (United States) Vol. 77:9; ISSN 0149-1423; ISSN AABUD2
- Country of Publication:
- United States
- Language:
- English
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020200* -- Petroleum-- Reserves
Geology
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03 NATURAL GAS
030200 -- Natural Gas-- Reserves
Geology
& Exploration
CENOZOIC ERA
CORRELATIONS
DEVELOPED COUNTRIES
DRILL CORES
GEOLOGIC AGES
GEOLOGIC FORMATIONS
GRAIN SIZE
LOUISIANA
MICROSTRUCTURE
NORTH AMERICA
PERMEABILITY
PLEISTOCENE EPOCH
PLIOCENE EPOCH
POROSITY
QUATERNARY PERIOD
SAND
SIZE
TERTIARY PERIOD
USA