| Additives | Components | Content (wt.%) |
|---|---|---|
| -- | Water | -- |
| -- | Clay | 4~5 |
| pH-adjusting agent | Sodium hydroxide | 0.5 |
| viscosifier | PAMS copolymer | 1.0 |
| viscosifier | Amphoteric sulfonated polymer | 0.5 |
| Filtrate loss reducer | Sulfonated phenolic resin | 4 |
| Filtrate loss reducer | Lignosulfonate | 4 |
| Weighting material | Barite | -- |