Which option is a legitimate method used to place grout in the annular space between the well face and the casing?

• A. Tremie pour and pumping; dump bailer; water pressure driving
• B. Vacuum injection; jet grouting; air-lift
• C. Gravity fill; manual tamping; steam injection
• D. Dry packing; vibration compaction; cement mixing

Answer: (A)

Placing grout in the annular space around a well casing relies on methods that keep the grout intact as it moves into the space and fills voids without segregation. The tremie pour and pumping method, a dump bailer, and using water pressure to drive the grout are all established ways to achieve that.

Tremie pour and pumping involves a sealed pipe that remains wetted as grout is introduced. This keeps the grout from mixing with the surrounding water and groundwater, allowing a continuous grout column to travel down to the bottom and displace water upward, which helps fill the entire annulus evenly.

A dump bailer is a tool dropped into the borehole, filled with grout, and released at the bottom. It deposits grout directly where needed, which is especially useful for filling portions of the annulus that are difficult to reach with pumping alone, helping to ensure complete coverage behind the casing.

Water pressure driving uses controlled pressure to push grout into the annular space, promoting penetration into small gaps and ensuring the grout advances into all portions of the annulus rather than simply pooling near the top or along the walls.

Other listed methods aren’t typically used for this specific purpose: they’re geared toward different ground-improvement or construction needs, and wouldn’t provide the controlled, bottom-up placement and full filling of the annular space that tremie placement, dump bailers, and pressurized grout injection offer.