NQUD Level Wireline Core Drilling Tool Overshot

NQUD Horizontal Wireline Overshot is a professional wireline coring fishing tool specially designed for horizontal drift drilling, tunnel advanced exploration and upward inclined boreholes. It matches NQU series horizontal wireline coring drill rods and inner tube assemblies.
Optimized for horizontal working conditions such as no gravity feeding, high borehole friction and water gushing, this overshot is hydraulically driven into position by drilling mud. It can retrieve the core barrel efficiently without tripping the whole drill string, greatly improving horizontal drilling efficiency in tunnel and underground mine projects.
Equipped with torsion-release lifting ring, built-in jarring mechanism and self-locking anti-drop fishing head, the NQUD overshot ensures smooth running, firm grabbing and reliable anti-drop performance. The main body is made of high-strength 40Cr steel with heat treatment, and the fishing dogs are alloy quenched for high wear resistance. Compact, durable and easy to maintain, it fully complies with DCDMA standards and is widely interchangeable with mainstream drilling tools.
Certifications: ISO, RoHS, MSDS

1. Hydraulic feeding design dedicated for horizontal boreholes
Customized for medium-size NQ horizontal and inclined holes. Instead of relying on gravity drop used in vertical-hole overshots, it is pushed downhole by drilling mud pressure, solving the difficulty of free sliding in horizontal boreholes and suiting conventional horizontal coring in tunnels and underground drifts.
2. Self-locking anti-drop structure for high safety
Equipped with 3-piece high-strength alloy fishing dogs plus rotary locking sleeve for double self-locking protection. It locks automatically once engaged with the inner tube spear head. No slipping under vibration, mud erosion or negative pressure pulling, completely avoiding inner tube falling and core loss accidents.
3. Built-in buffer jarring assembly for releasing stuck tools
Integrated jarring cylinder and jarring rod tackle inner tube sticking caused by high borehole friction, rock powder deposition and mud adhesion. Quick jarring force generated by surface lifting releases jams effectively and cuts down downhole malfunctions.
4. Tapered centralizing guide for smooth running
Front tapered guide perfectly matches the inner passage of NQU horizontal drill rods. No scratch on rod inner wall and no blockage during feeding, enabling the overshot to reach the hole bottom steadily and rapidly.
5. Torsion-releasing swivel lifting ring
The lifting ring assembly is fitted with thrust bearing and rotary joint, which automatically eliminates wire rope torsion during lifting to prevent twisting and breaking of cables and improve underground operation safety.
6. Standardized size & easy disassembly
Manufactured in accordance with DCDMA standards, fully compatible with NQU medium-bore horizontal wireline drill rods and inner tube assemblies. Modular overall structure allows quick on-site replacement of worn parts without special tools.

1. Customized for medium-bore horizontal drilling with wider applicability
Optimized for mainstream NQ medium-bore horizontal drilling conditions, suitable for most tunnel advanced geological prediction, mine water detection and geological exploration projects. It features higher load capacity and wider application scenarios compared with small-bore models.
2. No tripping entire drill string to retrieve cores, greatly boost construction efficiency
Complete core barrels can be pulled out via wireline without lifting the whole drill string, shortening auxiliary tripping time and accelerating horizontal drift drilling progress.
3. High-strength wear-resistant materials for extended service life
Main body adopts quenched & tempered 40Cr steel; fishing dogs are treated by alloy carburizing and quenching. High hardness, impact resistance and anti-abrasion against sandy mud and broken formations, much more durable than ordinary overshots.
4. Low failure rate to cut construction costs
Integrated anti-drop, jam releasing, guiding and torsion releasing functions reduce stuck drilling, tube dropping and re-fishing work, minimizing downtime and maintenance & rework expenses.
5. Complete certifications for domestic & overseas projects
Certified with ISO, RoHS and MSDS. Universal standard size fits mainstream domestic and foreign horizontal wireline coring rigs and tools, supporting engineering bidding and export matching.