The role of organic acids in feldspar and quartz dissolution at 100C/347 bars: An experimental study
- Texas A and M Univ., College Station (United States)
Water-soluble organic anions are capable of dissolving feldspar and quartz under diagenetic conditions and maintaining high levels of Al and Si in solution. It has been shown that abundant organic acids are released prior to and possibly during hydrocarbon generation. The combination of dissolution and complexing capacity suggests that organic acids may be of significant importance in mineral dissolution and secondary porosity development in sandstones in the diagenetic environment. Dissolution of albite and quartz was studied using flow-through hydrothermal vessels at 100C and 347 bars. Buffered 5,000 ppm acetate/500 ppm oxalate solutions (pH = 4.7) were passed through sand packs of 250-500 {mu}m Amelia albite (Ab{sub 97-99}) and Brazilian hydrothermal quartz. The solid starting material was cleaned ultrasonically to remove any adhering ultrafine particles. Organic species were analyzed using ion chromatography. Steady-state concentrations of SiO{sub 2} and Al average 237 ppm and 50 ppm, respectively. These values are significantly higher than predicted by the solubilities of common aluminosilicate clay minerals in water. This suggests that the amount of Al held in solution by complexing is very high, significantly reducing the amount of Al available for clay precipitation. The lack of authigenic aluminosilicates indicates the efficiency of the organics in removing and transporting Al and Si. Future work with aliphatic and aromatic organics, as well as inorganic acids, will allow comparison of the role of various aqueous species in mineral dissolution and secondary porosity development.
- OSTI ID:
- 5675790
- Report Number(s):
- CONF-910403-; CODEN: AABUD
- Journal Information:
- AAPG Bulletin (American Association of Petroleum Geologists); (United States), Vol. 75:3; Conference: Annual meeting of the American Association of Petroleum Geologists (AAPG), Dallas, TX (United States), 7-10 Apr 1991; ISSN 0149-1423
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
02 PETROLEUM
03 NATURAL GAS
FELDSPARS
SOLUBILITY
INTERSTITIAL WATER
ROCK-FLUID INTERACTIONS
ORGANIC ACIDS
SOLVENT PROPERTIES
QUARTZ
DIAGENESIS
DISSOLUTION
POROSITY
PRESSURE EFFECTS
RESERVOIR ROCK
SANDSTONES
TEMPERATURE EFFECTS
GROUND WATER
HYDROGEN COMPOUNDS
MINERALS
ORGANIC COMPOUNDS
OXIDE MINERALS
OXYGEN COMPOUNDS
ROCKS
SEDIMENTARY ROCKS
SILICATE MINERALS
WATER
580000* - Geosciences
020200 - Petroleum- Reserves
Geology
& Exploration
030200 - Natural Gas- Reserves
Geology
& Exploration