The kinetics of barite dissolution and precipitation in water and sodium chloride brines at 44--85[degrees]C

Journal Article · Sat May 01 00:00:00 EDT 1993 · Geochimica et Cosmochimica Acta; (United States)

DOI:https://doi.org/10.1016/0016-7037(93)90557-D· OSTI ID:6347760

Christy, A G ^[1]; Putnis, A ^[2]

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1. Univ. of Leicester (United Kingdom)
2. Univ. of Cambridge (United Kingdom)

Barite (BaSO[sub 4]) is an extremely insoluble salt which is of importance to the petroleum industry as a particularly intractable scaling agent. Barite precipitation in the wellbore environment generally requires mechanical removal, with considerable associated expense and loss of production. An understanding of the thermodynamics and kinetics of barite precipitation and dissolution is clearly important for prediction of where and how fast scaling is likely to occur. The dissolution rate of natural barite cleavage fragments was measured in deionized water and NaCl brines over the temperature range 44--85[degrees]C. Dissolution followed first-order kinetics, with an activation energy of 24.9 [+-] 10.1 kJ/mol. The observed insensitivity to stirring rate and low absolute value of the rate constant (extrapolated k at 25[degrees]C = 3.30 [+-] 1.31 [times] 10[sup [minus]3] L/m[sup 2] s) indicated desorption rather than volume diffusion as the rate-determining step. The NaCl concentration had no effect on k up to 0.1 M. Barite growth from supersaturated aqueous solutions was also studied. Precipitation followed a second-order rate law, k[sub 25[degrees]C] = 162 [+-] 65 L[sup 2]/sm[sup 2] mol, E[sub a] = 22.0 [+-] 14.3 kJ/mol, and was not sensitive to pH variation. A different rate law is likely to apply at high supersaturations, where a change in secondary growth morphology was observed. 16 refs., 5 figs., 2 tabs.

• OSTI ID: 6347760
• Journal Information: Geochimica et Cosmochimica Acta; (United States), Vol. 57:10; ISSN 0016-7037
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
02 PETROLEUM
BARITE
DISSOLUTION
KINETIC EQUATIONS
PRECIPITATION
PH VALUE
REACTION KINETICS
SCALING
TEMPERATURE RANGE 0273-0400 K
EQUATIONS
KINETICS
MINERALS
SEPARATION PROCESSES
SULFATE MINERALS
TEMPERATURE RANGE
400201* - Chemical & Physicochemical Properties
020300 - Petroleum- Drilling & Production