Product Overview
The Flow Activated Releasable Overshot is a differential pressure actuated releasable external retrieval fishing overshot specially developed for coiled tubing downhole workover salvage operations of recovering cylindrical tubular downhole fish assemblies that are not fitted with serviceable external fishing neck structure.
This external fishing overshot adopts a simplified integral mechanical structural layout with outstanding overall structural robustness and mechanical strength, capable of bearing complex downhole impact loads and long-term circulating fluid erosion during fishing construction. For release operation after finishing cylindrical tubular fish salvage tasks, the tool adopts a pure fluid throttling differential pressure actuation release design, completely eliminating the need for auxiliary shear pins or operation drop balls required by traditional releasable external fishing overshots. When surface pump circulates working fluid through the internal precision throttling nozzles of the fishing overshot, fluid throttling generates stable differential pressure drop, the pressure difference force will push the tool’s internal mandrel assembly to move downward, driving multiple groups of external grapple slip sets to retract inward to fully release the locked external cylindrical tubular fish downhole tool assembly.
The core flexible matching advantage of this fishing overshot lies in its multiple interchangeable external grapple slip size specifications: construction personnel can replace different outer diameter grapple slip assemblies to match cylindrical tubular fish with various outer diameter sizes, realizing flexible adaptation to different tubular fish dimension construction demands without replacing the entire fishing overshot body.
The Flow Activated Releasable Overshot is widely applicable to all coiled tubing downhole workover construction scenarios involving salvage recovery of external cylindrical tubular downhole fish assemblies without usable external fishing neck structure, including fallen tubing sections, damaged downhole tool outer barrels and other cylindrical tubular junk components lacking external fish neck.
The standardized product lineup covers outer diameter sizes ranging from 1-11/16" to 3-5/8", with matched fixed closed make-up length specifications, equipped with standard 1"AMMT, 1-1/2"AMMT, 2-3/8"PAC and NC26 bottom connection threads for universal compatibility with mainstream coiled tubing connectors and other downhole fishing workover service tools. Custom outer diameter, internal throttling nozzle flow passage size and interchangeable external grapple slip outer diameter specification customization are available upon customer technical drawing submission.
Complete Technical Specification Table
| PN Part Number | Outer Diameter OD | Inner Diameter ID | Make-Up Length (Closed) | Working Condition Grade | Bottom Connection Thread |
|---|---|---|---|---|---|
| L3071690120 | 1-11/16" | 0.39" | 20" | STD Standard | 1" AMMT |
| L3072125120 | 2-1/8" | 0.39" | 20" | STD Standard | 1-1/2" AMMT |
| L3072500120 | 2-1/2" | 0.39" | 20" | STD Standard | 1-1/2" AMMT |
| L3072875120 | 2-7/8" | 0.39" | 22.6" | STD Standard | 2-3/8" PAC |
| L3073125120 | 3-1/8" | 0.78" | 23" | STD Standard | 2-3/8" PAC |
| L3073625120 | 3-5/8" | 0.7" | 24.5" | STD Standard | NC26 |
Note: Custom outer diameter, customized internal throttling nozzle flow passage size and interchangeable external grapple slip outer diameter specification modification flow activated releasable fishing overshots are available via engineering consultation. This tool is designed for retrieving cylindrical tubular fish without serviceable external fishing necks; matched external grapple slip outer diameter must be confirmed according to the outer diameter size of target cylindrical fish during order placement.
Core Features & Advantages
Simplified Robust Integral Mechanical Structural Design: Compact streamlined integral mechanical layout with optimized high-strength alloy structural cross-section, outstanding overall structural rigidity and impact load resistance, capable of enduring repeated lifting and impact loads during downhole fishing operations, resistant to long-term completion fluid and formation circulating fluid erosion, effectively extending service life and reducing on-site mechanical failure risks.
Pure Flow Differential Pressure Actuated Release Mechanism, Zero Shear Pin / Drop Ball Dependency: The tool relies entirely on circulating fluid throttling pressure drop to trigger release action, no shear pins that risk premature shear failure or operation drop balls that risk wellbore jamming are required, eliminating two major common failure risks of traditional releasable external fishing overshots and greatly improving construction operation reliability.
Multiple Interchangeable External Grapple Slip Size Specifications: Complete series of replaceable external grapple slip assemblies with different outer diameter dimension options, construction crews can swap corresponding grapple slip sets to match cylindrical tubular fish with various outer diameter sizes, realizing flexible adaptation to different tubular fish dimension construction demands without whole-tool replacement, reducing tool inventory cost and construction preparation time.
Simple Stable Mandrel Downward Retraction Release Structure: Internal mandrel assembly driven by differential pressure drop moves linearly downward to synchronously retract multiple groups of external grapple slip sets inward, the mechanical transmission path is short and direct with few moving friction components, low wear and low failure rate, ensuring stable and reliable release action after reaching the set circulating flow threshold.
Specialized Design for Cylindrical Fish Without Usable External Fishing Necks: The external grapple slip clamping profile and radial expansion stroke are fully optimized to directly grip the outer cylindrical surface of tubular fish that do not have serviceable external fishing neck structure, filling the salvage operation demand for plain cylindrical downhole junk without fish neck.
Low Wellsite Operation Threshold, Simplified Construction Procedures: Two core operation processes are highly simplified: 1) Cylindrical fish capture: run the overshot to cover the outer cylindrical surface of target tubular fish, apply upward pull load to expand external grapple slips for locking and grabbing; 2) Cylindrical fish release: adjust surface pump circulating flow to reach preset release flow rate to complete grapple slip retraction and fish release action. No complex auxiliary operation steps such as drop ball delivery or shear pin impact jarring are needed, shortening wellsite operation time and reducing human error risks.
Full Outer Diameter Size Compatibility: Standard product series covers 1-11/16", 2-1/8", 2-1/2", 2-7/8", 3-1/8" and 3-5/8" outer diameter specifications, fully compatible with global mainstream medium-size coiled tubing assemblies for all external cylindrical tubular downhole fish salvage intervention demands.
Multi-Type Standard Thread Compatibility: All product models are equipped with universal 1"AMMT, 1-1/2"AMMT, 2-3/8"PAC and NC26 bottom connection threads, realizing seamless assembly with global mainstream coiled tubing bottom-hole assemblies and other supporting fishing workover tools without extra conversion subs.
Precision CNC High-Strength Alloy Manufacturing: Adopts precision CNC machining integral tool body, internal differential pressure throttling nozzle assembly, mandrel linear transmission matching components and interchangeable external cylindrical fish clamping grapple slip sets, featuring outstanding circulating fluid erosion resistance, repeated differential pressure actuation cycle fatigue resistance and structural stability, extending long-term continuous external cylindrical tubular fish salvage retrieval service life for downhole workover operations.
Application Scenarios
1. Coiled tubing downhole external cylindrical tubular downhole fish salvage recovery heavy-load intervention treatments, including fallen tubing sections, damaged downhole tool outer barrels and other cylindrical tubular junk components lacking serviceable external fishing neck structure
2. Conventional sweet crude oilfield flow differential pressure actuated releasable external fishing overshot cylindrical tubular junk salvage fishing workover service (STD standard service grade)
3. Downhole external cylindrical tubular fish salvage heavy workover projects requiring interchangeable external grapple slip size matching, shear-pin-free drop-ball-free release mechanism and stable mandrel linear retraction release structure
4. Long-term continuous repeated differential pressure throttling actuation safety protection for coiled tubing bottom-hole assemblies in onshore and offshore oilfield external cylindrical tubular downhole fish salvage recovery heavy workover intervention projects
Standard Delivery Package
Complete flow activated releasable fishing overshot integral pre-assembled unit including internal differential pressure throttling nozzle assembly, mandrel linear downward transmission mechanism and standard external cylindrical fish clamping base structure
Spare interchangeable external grapple slip kit with multiple outer diameter dimension specifications for on-site matching adjustment according to target cylindrical fish outer diameter size
Full factory inspection test report including repeated differential pressure throttling actuation cycle fatigue resistance test, integral tensile load test, mandrel linear downward stroke calibration test, external grapple slip cylindrical fish clamping locking stability test and release action reliability performance test data
Product dimension drawing and official installation & operation instruction manual, with detailed on-site cylindrical fish capture and circulating flow release threshold adjustment guidance, with clear reminder to confirm target cylindrical fish outer diameter size for grapple slip matching during order placement
Quality Warranty & After-Sales Service
Warranty Coverage: 12 months after factory shipment or 2000 cumulative differential pressure throttling actuation cycles, whichever condition is reached first
Full factory inspection: Each finished flow activated releasable fishing overshot passes integral tensile load test, repeated differential pressure throttling actuation cycle fatigue test, mandrel linear downward stroke calibration test, external grapple slip cylindrical fish clamping locking stability test and release action reliability performance test before factory delivery
Free professional technical support: Our oilfield downhole tool engineering team provides coiled tubing external cylindrical tubular fish salvage heavy workover tool string matching, outer diameter & interchangeable external grapple slip outer diameter size selection and release flow rate threshold adjustment consultation free of charge
Long-term spare parts supply: All interchangeable external grapple slip wear accessories and internal throttling nozzle assemblies are stocked with competitive factory bulk pricing
Custom development service: Support custom outer diameters, customized internal throttling nozzle flow passage sizes, interchangeable external grapple slip outer diameter specification modification, bottom thread profiles and special size flow activated releasable fishing overshots based on customer technical drawings
FAQ
Q1: What is the core function of a Flow Activated Releasable Overshot?
The Flow Activated Releasable Overshot is a differential pressure actuated releasable external retrieval fishing overshot dedicated to coiled tubing workover, used for salvage recovery of external cylindrical tubular downhole fish assemblies that are not equipped with serviceable external fishing neck structure. It features simplified robust integral mechanical structure; multiple interchangeable outer diameter external grapple slip sets are optional to match different cylindrical fish outer diameter sizes. For release operation, circulating fluid flows through internal precision throttling nozzles to create pressure drop, differential force pushes internal mandrel downward to retract external grapple slips and fully release the caught cylindrical fish assembly. The tool eliminates shear pins and drop balls entirely, and it is widely applied for coiled tubing downhole external cylindrical tubular junk salvage fishing workover construction such as fallen tubing sections and damaged tool outer barrels without usable external fish neck.
Q2: What three core structural advantages does this flow activated releasable fishing overshot own?
1. Simplified robust integral mechanical structural design, compact streamlined integral mechanical layout with optimized high-strength alloy structural cross-section, outstanding overall structural rigidity and impact load resistance, capable of enduring repeated lifting and impact loads during downhole fishing operations, resistant to long-term completion fluid and formation circulating fluid erosion, effectively extending service life and reducing on-site mechanical failure risks; 2. Pure flow differential pressure actuated release mechanism without shear pins or drop balls, eliminating two major common failure risks of traditional releasable external fishing overshots: premature shear pin rupture and drop ball wellbore jamming, greatly improving on-site construction operation reliability and reducing unexpected downhole accident risks; 3. Multiple interchangeable external grapple slip size specifications with flexible dimension matching capability, complete series of replaceable external grapple slip assemblies with different outer diameter dimension options, construction crews can swap corresponding grapple slip sets to match cylindrical tubular fish with various outer diameter sizes, realizing flexible adaptation to different tubular fish dimension construction demands without whole-tool replacement, reducing tool inventory cost and construction preparation time.
Q3: What outer diameter sizes do these flow activated releasable fishing overshots support?
Our standard production lineup fully covers outer diameters: 1-11/16", 2-1/8", 2-1/2", 2-7/8", 3-1/8" and 3-5/8". All models adopt universal 1"AMMT, 1-1/2"AMMT, 2-3/8"PAC and NC26 bottom connection threads compatible with global mainstream coiled tubing connector assemblies and other supporting downhole fishing workover tools.
Q4: What is the standard production lead time for bulk purchase orders?
All standard PN part numbers are kept in factory inventory, goods can be delivered within 7–15 working days. Customized flow activated releasable fishing overshots with special outer diameters or customized internal throttling nozzle flow passage sizes & interchangeable external grapple slip outer diameter specifications require 20–35 working days production cycle, subject to total order quantity and customization scope.
Get Custom Datasheet & Factory Quote
We are a professional OEM & ODM manufacturer focused on full series coiled tubing heavy workover and washing downhole service tools, covering flow activated releasable fishing overshots, flow activated releasable fishing spears, flow activated releasable JDC running/pulling tools, flow activated releasable GS fishing tools, bi-direction mechanical accelerators, bi-direction hydraulic accelerators, bi-direction hydraulic jars, up-stroke hydraulic jars, bi-direction mechanical jars, up-stroke mechanical jars, thru tubing cutters, high expansion four-blade hydraulic anchors, annular grapple hydraulic anchors, heavy duty motorhead assemblies, concentric coiled tubing wash tools (multi-mode), concentric coiled tubing wash tools (single mode), slimline wash tools (double dart), slimline wash tools (double flapper), storm wash tools, low speed spinning jetting tools, multiple points rotary wash tools, fast rotary wash tools, conical wash tools, multi-nozzle wash tools, bull nose wash tools, big ID large bore motorhead assemblies, heavy duty integrated motorhead assemblies, big ID hydraulic disconnects, dog latch interchangeable piston hydraulic disconnects, heavy duty high torsion hydraulic retrievable disconnects, mechanical hydraulic dual-action disconnects, mechanical adjustable shear tension disconnects, dual activated dual-action circulation valves, ball activated shear pin circulation valves, burst disc pressure circulation valves, double dart dual-stage sealing check valves, double flapper dual-stage sealing check valves, big ID single flapper check valves, grapple dimple composite connectors, grub screw heavy-duty connectors, double dimple-on connectors, single dimple-on connectors, double roll-on connectors, single roll-on connectors, internal grapple connectors, external grapple connectors, logging heads and tubing hangers. Every finished product undergoes strict factory tensile load, repeated differential pressure throttling actuation cycle fatigue, mandrel linear downward stroke calibration, external grapple slip cylindrical fish clamping locking stability and release action reliability performance testing, with complete material inspection certification attached to each shipment. Please share your detailed technical requirements, including target outer diameter size, required interchangeable external grapple slip outer diameter specification, matched target cylindrical tubular fish outer diameter dimension, working environment and all customized specification demands. Our dedicated oilfield downhole tool engineering team will send complete detailed technical datasheets and competitive factory wholesale quotations within 24 business hours, and provide professional on-site cylindrical fish capture and circulating flow release threshold adjustment operation guidance, with clear confirmation reminder for target cylindrical fish outer diameter size during order placement.
