Hydrovac Support for Directional Drilling & Boring
7-step process guide with equipment, safety, and cost information.
Directional drilling support is a critical hydrovac application where hydrovac trucks work alongside horizontal directional drilling (HDD) rigs to provide potholing, bore pit excavation, and fluid management services. Nearly every directional drilling project requires hydrovac support for utility verification and entry/exit pit preparation.
Before a directional bore begins, hydrovac potholing is used to verify the exact location of all underground utilities along the bore path. This prevents cross-bores, which occur when a new utility is inadvertently drilled through an existing one. Cross-bores are a serious safety hazard, particularly when gas lines are bored through sewer laterals.
During drilling operations, hydrovac trucks excavate entry and exit pits, manage drilling fluid returns, and provide emergency excavation capability if the drill head encounters unexpected underground conditions. The coordinated operation of drilling and hydrovac crews is standard practice on directional drilling projects of all sizes.
Step-by-Step Process
Bore Path Utility Investigation
Pothole at every utility crossing point and at regular intervals along the planned bore path to verify exact utility positions and depths.
Entry Pit Excavation
Excavate the entry pit at the drill rig location, providing adequate depth and dimensions for the drill string entry angle and drill fluid management.
Exit Pit Excavation
Excavate the receiving pit where the drill head will emerge. Size the pit for the pullback operation and product pipe installation.
Intermediate Access Points
Excavate additional pits at splice points, change-of-direction locations, or where the bore path passes near critical utilities requiring monitoring.
Drill Fluid Management
Use the hydrovac to manage drilling fluid (bentonite slurry) returns during boring operations. Vacuum excess fluid from pits and surface returns.
Product Installation Support
Assist with product pipe pullback by maintaining clean pits and managing fluid during the installation phase.
Pit Backfill and Restoration
After product installation, backfill all entry, exit, and intermediate pits. Restore surfaces and clean the work area of drilling fluid.
Equipment Recommendations
- Mid-size hydrovac truck for potholing and pit excavation
- Large debris tank for managing drilling fluid volumes
- Extended hose for reaching multiple pit locations from one setup
- Quick-connect fittings for efficient hose reconfigurations
- Shaker screen or cyclone separator for recycling drilling fluid
Safety Considerations
- ⚠Pothole every utility crossing — cross-bores are a life-safety issue
- ⚠Monitor bore path for inadvertent returns (frac-outs) near waterways
- ⚠Maintain communication between hydrovac and drill rig operators
- ⚠Follow proper drilling fluid containment and disposal procedures
- ⚠Watch for utility damage during pullback operations
Cost Factors
- ●Number of potholes required along bore path
- ●Number and size of entry/exit pits
- ●Duration of drilling operation (standby time for hydrovac support)
- ●Drilling fluid volumes to manage
- ●Project length and number of mobilizations
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