1. Orientation Circulation State
- Workflow:
- The mud pump circulates drilling fluid downhole, which flows smoothly through the internal flow channel of the whipstock.
- Hydraulic pressure remains balanced at low levels, maintaining all components (slips, springs, orientation mechanism) in their initial positions.
- Purpose:
- Ensures precise alignment of the whipstock face with the target formation (accuracy ≤±1°).
- Prevents premature activation of the anchoring system.
2. Hydraulic Sealing State
- Activation: Increase mud pump flow rate to threshold (typically ≥800 L/min) after orientation.
- Workflow:
1. High-Flow Activation: Drilling fluid drives the sealing ball and expandable ball seat carrier downward.
2. Carrier Expansion:
- The carrier radially expands (200% diameter increase) upon reaching the lower chamber, locking against its shoulder.
- Material: Nitinol frame + oil-resistant rubber.
3. Ball Seating:
- The sealing ball seats onto a metal-to-metal seal at the bottom sub.
- Blocks internal flow (pressure rating ≥15,000 psi).
- Confirmation:
- Sudden pressure spike detected at surface confirms successful sealing.
- Triggers subsequent anchoring/window-cutting procedures.
Key Parameters
- Flow Threshold: 800–1,200 L/min (adjustable for hole size)
- Temperature Resistance: -40°C to 175°C
- Sealing Response Time: <30 seconds
- Reusability: ≥5 wells
Operational Workflow
1. Run in hole to target depth.
2. Orientation State: Circulate mud + calibrate azimuth with wireless gyro.
3. Sealing State: Increase flow to trigger ball-carrier expansion and flow path sealing.
4. Confirm sealing via pressure spike.
5. Set anchor by slacking off weight to shear pins.
6. Initiate cutting with mill assembly.
Case Study
- Well Conditions: Bohai Sea, Ø244.5mm casing at 3,200m MD.
- Results:
- Anchor set in 1.2 hrs (vs. 4 hrs conventionally).
- Window smoothness allowed Ø120mm BHA pass-through.
- $18,000 USD saved per run.
Core Innovations
- Fail-Safe Hydraulic Switching: Eliminates manual intervention using flow-rate automation.
- Metal Sealing: Ensures zero leakage in HP/HT environments.
- Self-Confirming Mechanism: Pressure spike provides real-time operational certainty.
- Industry Impact: Reduces side-tracking time by 60% while enhancing reliability in complex wells.
