Table 2.
Physico-chemical analysis of formation water collected from Gujarat oil fields.
| Parameter | Method | K#35 | K#655 | J#06 | J#188 | J#31 |
|---|---|---|---|---|---|---|
| pH | 7.7 ± 0.02 | 7.5 ± 0.01 | 7.6 ± 0.04 | 7.6 ± 0.02 | 8.1 ± 0.04 | |
| Anions (mg l-1) | ||||||
| Chloride | IS3025 Pt 32:1988 | 560 ± 2.6 | 300 ± 4.0 | 750 ± 2.3 | 1001 ± 3.3 | 651 ± 1.6 |
| Fluoride | APHA 4500 | 0.12 ± 0.01 | 0.55 ± 0.01 | 0.11 ± 0.01 | 0.70 ± 0.02 | ND |
| Sulfate | IS3025 Pt 32:1988 | 44 ± 0.4 | 119 ± 1.2 | 43.8 ± 0.5 | 32.3 ± 0.9 | 50 ± 0.8 |
| Elements (ppm) | ||||||
| Carbon | APHA:1350 | 500 ± 1.6 | 510 ± 4.0 | 1150 ± 2.6 | 300 ± 3.7 | 210 ± 1.2 |
| Hydrogen | APHA:1350 | 22 ± 0.4 | 20 ± 0.8 | 0.11 ± 0.001 | 140 ± 2.1 | 80 ± 1.2 |
| Nitrogen | APHA:1350 | 12 ± 0.5 | 31 ± 0.8 | 43.8 ± 0.4 | 37 ± 0.8 | 36 ± 0.4 |
| Sulfur | APHA:1350 | 17 ± 0.2 | 11 ± 0.2 | 11.3 ± 0.3 | 11 ± 0.3 | 51 ± 1.6 |
| Heavy metals (mg l-1) | ||||||
| Arsenic | IS3025 PT 37:1988 | ND | ND | ND | ND | ND |
| Cadmium | APHA3100(B) | ND | ND | ND | ND | ND |
| Chromium | APHA3500(B) | ND | ND | ND | ND | ND |
| Copper | APHA3111(B) | ND | ND | ND | ND | ND |
| Zinc | APHA3100(B) | ND | ND | ND | ND | ND |
| Silver | APHA3113(B) | ND | ND | ND | ND | ND |
| Nickel | APHA3111(B) | ND | ND | ND | ND | ND |
| Iron | APHA3100(B) | 0.22 ± 0.001 | 2.18 ± 0.07 | 0.12 ± 0.001 | 0.13 ± 0.002 | 0.46 ± 0.01 |
ND means not detected; standard deviation (±).