Releasing and Circulating Overshot: Advanced Fishing Tool with Emergency Disconnect Capability
The Fishing Operation Challenge
Traditional fishing tools face critical limitations:
⚠️ Irreversible engagement – once engaged, cannot be released if stuck
⚠️ No circulation capability – cannot circulate while attempting recovery
⚠️ Single-point failure – if tool gets stuck, creates additional fishing job
⚠️ Limited flexibility – cannot adjust gripping force during operation
Our releasing and circulating overshot delivers:
✅ Positive release capability – can disengage even after setting
✅ Full circulation capacity – pump while fishing to free stuck fish
✅ Adjustable gripping force – control engagement pressure
✅ Proven reliability – 95% success rate in fishing operations
Working Principle & Mechanical Design
Dual-Function Mechanism
| Operation Mode | Mechanical Action | Functional Advantage |
|---|---|---|
| Engagement | Slip assembly grips fish with controlled force | Secure holding without damaging fish |
| Circulation | Fluid passes through tool body to fish top | Free stuck fish with hydraulic action |
| Release | Reverse rotation disengages slip mechanism | Emergency escape if tool gets stuck |
| Recovery | Maintains grip during retrieval | Positive control of recovered fish |
Approach Fish
Engage with Controlled Force
Circulate to Free Fish
Recovery Successful?
Retrieve Fish to Surface
Reverse Rotation to Release
Retrieve Overshot Safely
Job Complete
Plan Alternative Approach
Technical Specifications
| Parameter | Specification |
|---|---|
| Size Range | 2-7/8″ to 9-5/8″ OD (all standard sizes) |
| Working Capacity | 50-300 tons (size dependent) |
| Pressure Rating | 5,000psi circulating pressure |
| Release Mechanism | Left-hand rotation with slight pickup |
| Grip Range | 15-25% of tool OD variation |
| Materials | 4140HM steel, hardened slips, wear-resistant guides |
| Connections | API REG, IF, FH (standard and premium) |
| Compliance | API Spec 7-1, API RP 7G |
Operational Advantages
Safety & Control
Emergency Release Capability:
- Left-hand rotation disengages slips even under load
- No secondary fishing jobs – tool can always be recovered
- Controlled grip force prevents damaging fragile fish
Circulation While Fishing:
- Pump chemicals or spots directly to fish top
- Hydraulic hammer effect to free stuck fish
- Maintain well control throughout fishing operation
Efficiency & Reliability
Proven Success Metrics:
- 95% success rate in first fishing attempt
- 80% faster than conventional fishing methods
- Zero incidents of overshot becoming stuck irretrievably
Field Applications & Performance Data
Application Scenarios
- Stuck Pipe Recovery: Free and recover stuck drill pipe or collars
- Fallen Object Retrieval: Recover tools or equipment dropped in hole
- Broken Tool Recovery: Engage and retrieve fractured tool joints
- Emergency Situations: Reliable performance in critical well control scenarios
