Case History Discussion:
The objective was to displace 17.5 lb/gal diesel oil base mud with filtered 10 lb/gal NaCl completion fluid. This task was to be accomplished utilizing a direct displacement. This would reduce costly disposal fees of additional fluids.
Rig-Chem designed a displacement package utilizing specialized surfactants and viscosifiers to clean and water wet all surfaces. The surfactant package designed works under high turbulence eliminating needed contact time, while reducing rig time.
By utilizing Rig-Chem displacement model software operations were prepared for actual rates and pressures that would be experienced.
Wellbore Information
Land Rig
| PBTD | 13,070 ft |
| Casing 1 | 9 5/8 in |
| Casing 2 | 7 5/8 in |
| Workstring 1 | 5 in |
| Workstring 2 | 3 1/2 in |
| DOBM Mud | 17.5 lb/gal |
| NaCl | 11.2 lb/gal |
| Volume | 764 bbls |
| Direct Displacement |
Project Results:
- All surface equipment was cleaned
- Job was pumped as designed
- Rotation & reciprocation of workstring was maintained through displacement
- Spacers returned on time and easily recognized
- Minimum interface < 25 bbls.
- Immediately after spacers returned to surface completion fluid was visually clean and proper density
- Workstring and clean out tools came out clean and water wet after displacement ( Picture on Right )
- Job was done in a safe and professional manner, having no personnel or environmental recordables