Low enthalpy geothermal fluids from the Paris Basin; Oxidation-reduction state and consequences for the prediction of corrosion and sulfide scaling

Journal Article · Sun Jan 01 00:00:00 EST 1989 · Geothermics (International Journal of Geothermal Research and its Applications); (UK)

DOI:https://doi.org/10.1016/0375-6505(89)90102-8· OSTI ID:5794886

Criaud, A; Fouillac, C ^[1]; Marty, B ^[2]

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1. Inst. Mixte de Recheres Geothermiques, BRGM, BP 6009, 45060 Orleans Cedex (FR)
2. Lab. de Magmatologie et Geochimie Inorganique et Experimentale, Univ. Pierre et Marie Curie, 75252 Paris Cedex (FR)

Analytical data for redox components (sulfur, carbon and nitrogen species) in geothermal fluids are given for 45 wells of the Paris sedimentary basin. They are interpreted with a view to improving knowledge of the oxidation-reduction state of the system. Direct measurement with a platinum electrode is related to hydrogen sulfide content but does not represent the potential of the fluid within the aquifer. Computed values of apparent Nernst potentials for HS{sup {minus}}/SO{sub 4}{sup 2{minus}}, N{sub 2}/NH{sub 4}{sup +}, CO{sub 2}/CH{sub 4}, organic matter/CO{sub 2}, H{sup +}/H{sub 2} redox couples range from {minus}0.35 to {minus}0.15 volts/NHE. The occurrence of mineral redox buffers is also investigated. The non-consistency of the calculated results shows that there is a lack of overall redox equilibrium in the aquifer. Despite this fact, the use of a redox parameter is discussed, in order to describe and forecast by chemical models the corrosion and scaling effects within the tubing. Pyrite, mackinawite, pyrrhotite and other iron sulfides are present. Calculations based upon nitrogen or carbon components do not allow an accurate prediction of the nature of the minerals encountered. The occurrence of microenvironments with very reducing conditions is emphasized to explain the formation of such minerals.

• OSTI ID: 5794886
• Journal Information: Geothermics (International Journal of Geothermal Research and its Applications); (UK), Vol. 18:5/6; ISSN 0375-6505
• Country of Publication: United States
• Language: English

Related Subjects

15 GEOTHERMAL ENERGY
FRANCE
GEOTHERMAL WELLS
CORROSION
CALCULATION METHODS
ENTHALPY
FORECASTING
IRON SULFIDES
REDOX REACTIONS
SCALING
SEDIMENTARY BASINS
CHALCOGENIDES
CHEMICAL REACTIONS
EUROPE
GEOLOGIC STRUCTURES
IRON COMPOUNDS
PHYSICAL PROPERTIES
SULFIDES
SULFUR COMPOUNDS
THERMODYNAMIC PROPERTIES
TRANSITION ELEMENT COMPOUNDS
WELLS
WESTERN EUROPE
150903* - Geothermal Engineering- Corrosion
Scaling & Materials Development