Staged Cementing for Shale Gas Well ( Double-SCem )
-
Characteristic of Double-SCem SystemⅠ The lead Slurry of double-SCem is specially designed with property of low-density, while the tail slurry is designed with property of high-performance to prevent gas channeling. The density of lead slurry is designed as 1.45～1.60g/cm³.
Ⅱ The density of lead slurry in Double-SCem is designed as 1.90g/cm³. The elastic and plasticizer compounds are added into the cement, enhancing its pressure ratings and preventing wellhead pressurized. The additives are optimally configured to secure its compatibility with cement and wellbore fluid.
Configuration and Performance of Lead Slurry in Double-SCem
| Product S/N | Additives Name | Dosage,%（BWOC） | Dosage,%（BWOC） | Dosage,%（BWOC） |
| Density of Lead Slurry（g/cm³） | 1.60 | 1.50 | 1.45 | |
| Dry Blending | ||||
| JHGG | Cement | 100 | 100 | 100 |
| CP-52 | Bead | 15 | 22 | 30 |
| CP-53 | Micron-silica | 8 | 12 | 12 |
| G403 | Toughening Agent | 2 | 2 | 3 |
| G310S | Fluid Loss Control Agent | 2.5 | 2.5 | 2.5 |
| G401 | Expansion Agent | 2.5 | 2.5 | 2.5 |
| Wet Blending | ||||
| GH-9 | Retarder | 1.0 | 1.2 | 1.1 |
| Water/Cement Ratio | 0.66 | 0.75 | 0.78 | |
| Item | Test Result | ||
| Density,g/cm³ | 1.60 | 1.50 | 1.45 |
| Slump Test,cm | 23.0 | 23 | 23 |
| Thickening Time,min | 267 | 290 | 255 |
| （40～100）Bc,min | 2 | 1 | 2 |
| Free Fluid,% | 0 | 0 | 0 |
| API Filtration Loss,mL | 38 | 36 | 36 |
| Pressure Rating（30℃×2.1MPa×48h）,MPa | 11 | 9.7 | 8.6 |
| Deposit Stabilization | 0 | 0 | 0.01 |
Configuration and Performance of Tail Slurry in Double-SCem
| Product S/N | Name | Dosage,%（BWOC） |
| Density of Tail Slurry（g/cm³） | 1.90 | |
| JHGG | Cement | 100 |
| CP-53 | Micro Silica | 2 |
| Plugging Fiber | 0.3 | |
| G310S | Fluid Loss Control Agent | 2.5 |
| G401 | Expansion Agent | 2 |
| GH-9 | Retarder | 0.8 |
| Water/Cement Ratio | 0.45 | |
| Item | Result |
| Density,g/cm³ | 1.90 |
| Slump Test,cm | 22.0 |
| Thickening Time,min | 173 |
| （40～100）Bc,min | 1 |
| Free Fluid,% | 0 |
| API Filtration Loss,mL | 34 |
| Pressure Rating(30℃×2.1MPa×48h),MPa | 20 |
| Sedimentary Stabilization | 0 |
