Experimental determination of smectite hydration states under diagenetic conditions

Conference · Sun Apr 01 04:00:00 EST 1984 · Am. Assoc. Pet. Geol., Bull.; (United States)

OSTI ID:6641981

Colten, V A

Knowledge of the hydration state of smectite under burial diagenetic conditions is necessary for the interpretation of the smectite to illite transformation, abnormal fluid pressure development, and reservoir properties. Simple changes in fluid composition, pressure, or temperature have been thought to affect the nu calculated for 80 cases of kerogen maturation at maximum temperature show a strong linear relationship (r = 0.77). The pseudo Eanges, suggest this occurs in 10/sup 6/-10/sup 7/ years. When plotted on an Arrhenius diagram (ln k versus l/T), reaction rate constantstion (to the 99% level). Geologic field data, and kerogen maturation experiments extrapolated to geologic time and temperature rer, (high E/sub a/) reactions geologically significant. Thus, the functional reaction to essentially complete hydrocarbon generaCheto montmorillonite in 1 molal NaCl solution under 15.1 MPa (2200 psi) pressure, to at least 175/sup 0/C, and in the same solution under 3.4 MPa (500 psi) to 125/sup 0/C. Two layers of water are also retained by Cheto montmorillonite in 5 molal NaCl solution 200/sup 0/C under pressures of 4.83 MPa (700 psi) and 46.2 MPa (6700 psi). This experimental evidence contradicts the previously suggested mechanism for generating fluid overpressuring in shales by simple thermal dehydration of smectite under burial conditions. Experiments done with dilute NaCl solutions demonstrate the effect of concentration on the swelling of smectite at depth, while experiments with KCl solutions illustrate the effect of the interlayer cation on the hydration state of the clay.

• Research Organization: Univ. of Illinois, Urbana
• OSTI ID: 6641981
• Report Number(s): CONF-8405216-
• Conference Information: Journal Name: Am. Assoc. Pet. Geol., Bull.; (United States) Journal Volume: 68:4
• Country of Publication: United States
• Language: English

Related Subjects

02 PETROLEUM
020200* -- Petroleum-- Reserves
Geology
& Exploration
03 NATURAL GAS
030200 -- Natural Gas-- Reserves
Geology
& Exploration
ALUMINIUM COMPOUNDS
ALUMINIUM SILICATES
CLAYS
DIAGENESIS
FLUID MECHANICS
HYDRATION
MECHANICS
MINERALS
OXYGEN COMPOUNDS
RESERVOIR ROCK
SILICATE MINERALS
SILICATES
SILICON COMPOUNDS
SMECTITE
SOLVATION