Product Overview
The Grub Screw Connector is a heavy-load external coiled tubing connection fitting built with exceptional tensile strength and outstanding torsion resistance, designed to cooperate with dedicated grub screw crimping tools for field assembly. Operators first press indentations on coiled tubing using special crimping equipment, then lock the tubing firmly inside the connector recesses with 16 knurled anti-drop grub screws to form a stable mechanical linkage between the connector and coiled tubing. This connector is engineered for severe heavy-duty downhole intervention work, including drilling, cutting, fishing and sidetracking operations. It adopts a dual independent O-ring sealing design to sustain stable high-pressure sealing performance amid fluctuating wellbore temperature and pressure. Two complete service grades are provided to match diverse reservoir environments: STD standard grade for conventional sweet oil wells free of hydrogen sulfide corrosive media, and H₂S sour service grade manufactured with sulfur-resistant alloy for high-H₂S corrosive sour gas well working conditions. The standardized product lineup covers coiled tubing sizes ranging from 1.25" to 2-3/8", with matched outer diameter, inner diameter and make-up length specifications, equipped with standard AMMT and PAC bottom connection threads for universal compatibility with mainstream downhole service tools. Custom tubing dimensions, wall thickness and anti-sulfur passivation coatings are available upon customer technical drawing submission.
Complete Technical Specification Table
| PN Part Number | CT Coiled Tubing Size | Outer Diameter OD | Overall Length | Number of Grub Screws | Service Grade | Bottom Connection | Max Differential Pressure | Max Tensile Load |
|---|---|---|---|---|---|---|---|---|
| GSC-125-STD | 1.25" | 1.85" | 10.0" | 16 | STD | 1" AMMT | 10,000 PSI | 40,000 LBS |
| GSC-125-HS | 1.25" | 1.85" | 10.0" | 16 | H₂S | 1" AMMT | 10,000 PSI | 40,000 LBS |
| GSC-150-STD | 1.50" | 2.10" | 10.5" | 16 | STD | 1-3/16" AMMT | 10,000 PSI | 50,000 LBS |
| GSC-150-HS | 1.50" | 2.10" | 10.5" | 16 | H₂S | 1-3/16" AMMT | 10,000 PSI | 50,000 LBS |
| GSC-175-STD | 1.75" | 2.35" | 11.0" | 16 | STD | 1-3/16" AMMT | 10,000 PSI | 60,000 LBS |
| GSC-175-HS | 1.75" | 2.35" | 11.0" | 16 | H₂S | 1-3/16" AMMT | 10,000 PSI | 60,000 LBS |
| GSC-200-STD | 2.00" | 2.60" | 11.5" | 16 | STD | 1-1/2" AMMT | 10,000 PSI | 80,000 LBS |
| GSC-200-HS | 2.00" | 2.60" | 11.5" | 16 | H₂S | 1-1/2" AMMT | 10,000 PSI | 80,000 LBS |
| GSC-237-STD | 2.375" | 2.98" | 12.0" | 16 | STD | 1-1/2" AMMT | 10,000 PSI | 100,000 LBS |
| GSC-237-HS | 2.375" | 2.98" | 12.0" | 16 | H₂S | 1-1/2" AMMT | 10,000 PSI | 100,000 LBS |
Core Features & Advantages
Ultra-high tensile strength and superior torsion resistance, capable of enduring extreme heavy pulling, twisting and bending loads during downhole drilling, cutting, fishing and sidetracking operations
16 knurled anti-drop grub screws engaging with pre-formed indentations distribute load evenly, providing exceptional tensile and torsional capacity for the most demanding heavy-duty downhole intervention work.
Field-installable grub screw system, quick and simple assembly using standard hydraulic crimping tools, without complex welding or threading procedures
Grub screw connection allows rapid field assembly with common hydraulic crimping tools, eliminating specialized welding equipment requirements.
16 multi-directional knurled anti-drop grub screws, even load distribution, anti-loosening performance to prevent connection failure under continuous vibration and heavy impact loading
16 knurled grub screws arranged radially provide redundant load paths with anti-loosening characteristics essential for severe vibration and impact downhole environments.
Dual independent O-ring sealing structure, providing stable leak-proof high-pressure sealing performance under fluctuating downhole temperature and pressure conditions
Two independent O-ring seal stacks ensure reliable wellbore isolation across the CT-to-connector interface under cyclic pressure and temperature loading.
Dual service grade design: STD standard version for conventional oil wells, H₂S sulfur-resistant version for highly corrosive sour gas well working environments
STD grade for routine sweet wells; H₂S grade with anti-sulfur material per NACE MR-0175 for sour gas downhole corrosive conditions.
Complete size series compatible with 1.25", 1.5", 1.75", 2", 2.375" standard coiled tubing, covering all mainstream coiled tubing service specifications
Full range from 1.25" through 2.375" covers all common CT diameters for standard downhole intervention operations.
Precision CNC machined high-strength alloy steel body, excellent wear, tensile and torsion resistance to extend continuous downhole service cycle
CNC-machined alloy steel construction provides long service life in abrasive and high-load downhole environments.
Customizable indentation depth, grub screw thread specifications and anti-sulfur surface passivation coatings to meet unique downhole tool connection requirements
Custom indentation patterns, screw configurations, thread forms and anti-corrosion coatings are available based on customer technical drawings.
Application Scenarios
1. Heavy-load coiled tubing drilling, cutting, fishing and sidetracking downhole intervention treatments
2. Conventional sweet crude oil well heavy workover and coiled tubing intervention service (STD standard service grade)
3. High-H₂S sour gas well corrosive environment heavy-duty coiled tubing string connection operations (H₂S sour service grade)
4. Sand washing, gas lifting and thru-tubing perforating auxiliary heavy-load coiled tubing extension construction
5. Long-term heavy pulling and torque transmission coiled tubing service in onshore and offshore oilfields
Standard Delivery Package
One complete grub screw connector main body with pre-installed 16 knurled anti-drop grub screws
Matching sealing assembly spare parts kit for field maintenance
Full factory inspection test report including tensile load, torque and high-pressure sealing test data
Product dimension drawing and official installation & operation manual
Quality Warranty & After-Sales Service
Warranty Coverage: 12 months after factory shipment or 2000 cumulative working hours, whichever condition is reached first.
Full factory inspection: Each finished connector passes tensile load, torque resistance and high-pressure sealing performance testing before delivery.
Free professional technical support: Our oilfield downhole tool engineering team provides installation guidance, parameter matching and operation consultation.
Long-term spare parts supply: All sealing wear parts and grub screw components are stocked with competitive factory bulk pricing.
Custom development service: Support custom indentation specifications, grub screw configurations and special size connectors based on customer technical drawings.
FAQ
Q1: What is a Grub Screw Connector and how does it work?
A1: A Grub Screw Connector uses 16 knurled anti-drop grub screws tightened radially into pre-formed indentations on the coiled tubing outer wall, creating a high-strength mechanical interlock for heavy-duty downhole intervention operations.
Q2: What coiled tubing sizes are available?
A2: Standard sizes cover CT diameters from 1.25" through 2.375". Custom sizes can be manufactured upon request.
Q3: What is the difference between STD and H₂S service grades?
A3: STD grade is for conventional sweet oil wells. H₂S grade with anti-sulfur material selection per NACE MR-0175 is for sour gas well corrosive environments.
Q4: Is this connector suitable for sidetracking operations?
A4: Yes, the 16-point grub screw locking design provides the high tensile and torsional capacity required for severe heavy-duty drilling, cutting, fishing and sidetracking operations.
Q5: Can I customize grub screw thread and indentation specifications?
A5: Yes, custom grub screw thread sizes, indentation depths and anti-corrosion coatings are available based on your technical drawings.
Get Custom Datasheet & Factory Quote
We are a professional OEM & ODM manufacturer focused on full series coiled tubing downhole service tools, covering grub screw connectors, grapple connectors, groove connectors, dimple connectors and all common BHA components. Please share your detailed technical requirements to our engineering team for professional technical proposal and factory direct price quotation.
