# Laboratory Measurements of Zeta Potential in Fractured
## 2 Materials and Methods
In the table, LS and HS correspond to low-salinity and high-salinity data, SS stands for sandstones, SP corresponds to sand packs, LS refers to limestones, SW is natural seawater from southern UK, TW is tap water and ALSW is artificial low-salinity water. Exact values of ionic strength in the table vary between 0.001 M and 0.01 M for low salinity, and between 0.5 M and 0.75 M for high-salinity data. For details, refer to the cited papers. The data sources are: a—[PERSON] et al. [31]; b—[PERSON] and [PERSON] [32]; c—[PERSON] et al. [42]; d—[PERSON] et al. [43]; e—[PERSON] and [PERSON] [44]; f—[PERSON] et al. [45]; g—[PERSON] et al. [35]; h—[PERSON] and [PERSON] [46]; i—[PERSON] et al. [47]; j—[PERSON] and [PERSON] [48]; k—[PERSON] et al. [34]; l—[PERSON] et al. [49]; m—[PERSON] et al. [50]; n—[PERSON] et al. [51]; o—[PERSON] et al. [52]. Figure 2: Zeta potential of gneiss samples compared with published data on other types of rocks. Circles denote NaCl solutions, triangles correspond to AGW and squares are ASW. Filled symbols correspond to confining pressure of 7 MPa. Low ionic strength is denoted by blue symbols while the high ionic strength data corresponds to red symbols. The solid lines that outline domains of reported data for carbonates and sandstones are based on the published data summarized in Table 2. \begin{table}
\begin{tabular}{c c c c c} \hline \hline \multirow{2}{*}{**Sample; Mineralology**} & \multirow{2}{*}{**Solution**} & \multicolumn{2}{c}{**Zeta Potential, mV**} & \multirow{2}{*}{**Source**} \\ \cline{3-3} \cline{5-5}  & & **LS** & **HS** & \\ \hline St Bess SS; 90\% quartz, \(<\)5\% clays & NaCl & \(-\)31 & \(-\)16 & a, c \\ \hline St Bees SS; 90\% quartz, \(<\)5\% clays & SW & N/A & \(-\)13 & a \\ \hline Doddington SS; 69\% quartz, 5\% clays & NaCl & \(-\)22 & \(-\)10 & e \\ \hline SP; \(>\)99\% quartz & TW & \(-\)100 & N/A & a \\ \hline SP; \(>\)99\% quartz & NaCl & \(-\)20 & \(-\)12 & d \\ \hline Berea SS; 90\% quartz, up to 4\% clays & NaCl & \(-\)20 & \(-\)17 & f \\ \hline Boise SS; 47\% quartz, 26\%  plagioclase, 3\% clays & NaCl & \(-\)20 & \(-\)20 & b \\ \hline Inada granite; N/A & KCl & \(-\)35 & N/A & g \\ \hline Westerly granite, 38\% plagioclase 29\% quartz & NaCl & \(-\)20 & N/A & h \\ \hline Crushed Westerly granite; N/A & KCl/NaCl & \(-\)65 & N/A & i \\ \hline Inada granite; N/A & KNO\({}_{5}\) & \(-\)70 & N/A & j \\ \hline \multicolumn{5}{c}{White shaded area} \\ \hline Ketton LS; 97\% calcite, 3\% dolomite & NaCl & N/A & \(-\)6 & k \\ \hline Estaillades LS; 95\% calcite, 4\% & NaCl & N/A & \(-\)6 & k \\ dolomite, 1\% anhydrite & NaCl & N/A & \(-\)9 & k \\ \hline Portland LS; 96.6\% calcite, 3.4\% quartz & NaCl & N/A & \(-\)1.25 & l \\ \hline Estaillades LS; 95\% calcite, 4\% & \multirow{2}{*}{SW} & N/A & \(-\)1.25 & \(\phantom{-}\)1 \\ \cline{1-1} dolomite, 1\% anhydrite & & & & \\ \hline Reservoir BA LS; N/A & ALSW & \(-\)4 & N/A & m \\ \hline Reservoir BD LS; N/A & ALSW & \(-\)10 & N/A & m \\ \hline Outcrop TE LS; \(>\)99\% calcite & Artificial & \(-\)15 & \(-\)2 & m \\ \hline Crushed Iceland spar; 100\% calcite & NaCl & \(-\)5 [n] & \(+\)4 [o] & n, o \\ \hline \end{tabular}
\end{table} 
Table 2: _Cont._