Temperature‐dependent streaming potentials: 2. Laboratory

Abstract

[1] Streaming potentials and zeta potentials were measured at equilibrium conditions, while at elevated temperatures of 23°-200°C and pressures of 20 MPa, on intact rock samples of Fontainebleau Sandstone, Berea Sandstone, and Westerly Granite using the oscillatory data collection method. The streaming potential coupling coefficient for Fontainebleau Sandstone decreased in magnitude from 195 nV/Pa at 23°C to 33 nV/Pa at 160°C before rising to 41 nV/Pa at 200°C. The Berea Sandstone coupling coefficient decreased in magnitude from 100 nV/Pa at 23°C to 23 nV/Pa at 160°C and then increased in magnitude to 100 nV/Pa at 200°C. The Westerly Granite coupling coefficient increased in magnitude from 23 nV/Pa at 40°C to 68 nV/Pa to 120°C, then decreased in magnitude to 43 nV/Pa at 160°C, and then increased in magnitude to 50 nV/Pa at 200°C. The zeta potential for all three samples increased in magnitude with increasing temperature, during these equilibrium experiments, which did not mirror the coupling coefficient responses. The temperature dependence of the zeta potential provides indications of possible chemistry changes occurring within sample, such as pH, ionic concentration, and ionic composition. These experiments confirm that knowledge of rock/solution chemistry is important for modeling coupling coefficients and zeta potentials. Results of the experimental work are compared to a model that predicts zeta potential variation with temperature, and reasonable correlations are obtained.

A review on electrokinetically induced seismo-electrics, electro-seismics, and seismo-magnetics for Earth sciences

“…Unfortunately the authors did not measure the fluid conductivity after equilibrium, and at the end of the temperature increase. But these results are coherent with those of Reppert and Morgan (2003b). The different behaviour of the SPC in sandstones and granite still needs further explanations, and is probably related to different behaviours in pH, surface charge density and dissociation constant in quartz-water or plagioclase/feldspar-water systems, as possible precipitation of secondary minerals.…”

“…However measurements of the SPC on sandstones and granite samples in the temperature range 20-200 • C, allowing very long equilibrium times such as 700-1200 h, showed that the SPC is not constant (Reppert and Morgan, 2003b). The SPC is decreasing in magnitude from 20 to 160 • C, from about 2×10 −7 to 3×10 −8 V Pa −1 (Fontainebleau sandstone) and from about 1 × 10 −7 to 2 × 10 −8 V Pa −1 (Berea sandstone), before increasing in magnitude up to 200 • , up to 4 × 10 −8 V Pa −1 (Fontainebleau sandstone) and 1 × 10 −7 V Pa −1 (Berea sandstone) for temperatures up to 200 • C. The fluid conductivity, initially 10 −3 mol L −1 NaCl, was increased from 0.01 to 0.13 S m −1 (for Fontainebleau sandstone).…”

“…Then a zeta potential value can be estimated according to the mineral/water system, and a SPC value deduced. Afterward, the effect of temperature on SPC can be estimated based on observations performed on simple systems at fluid conductivity about 0.1 S m −1 , as quartz-or granite water showing a decrease of a factor of 5 to 7 of the SPC from 20 to 160 • C (Berea and Fontainebleau sandstone, Reppert and Morgan, 2003b), or as an increase of a factor of 3 of the SPC from 20 to 120 to 200 • C (Westerly granite, Reppert and Morgan, 2003b;Inada granite, Tosha et al, 2003).…”

Frequency-Dependent Streaming Potential of Porous Media—Part 2: Experimental Measurement of Unconsolidated Materials

“…In this equation ΔP (Pa) is the fluid pressure difference, ε (F/m) is the dielectric constant of the fluid, η f (Pa.s) is the dynamic viscosity of the fluid, ζ (V) is the zeta potential, ΔV (V) is the streaming potential, σ f (S/m) is the electrical conductivity of the bulk fluid, Σ s (S) is the specific electrical conductance of the surface (i.e., that due to the double layer), σ (S/m) is the electrical conductivity of the mobile fluid, and Λ (m) is a characteristic length associated with the microstructure of the pore network [14][15][16][17][18]. The steady-state streaming potential is independent of the sample geometry.…”

Changes in Electrokinetic Coupling Coefficients of Granite under Triaxial Deformation

“…In laboratory experiments, zeta potential and streaming potential coefficients, fundamental quantities that characterize the electrokinetic effect, were measured for crushed rocks (e.g., [5,[17][18][19][20][21]) and for natural intact rocks (e.g., [22][23][24][25][26][27][28][29]) to determine the electrokinetic parameters as a function of pH, resistivity, permeability, or temperature. Jouniaux and Pozzi [23] measured the streaming potential coefficients of Fontainebleau sandstones under triaxial stress up to failure.…”