6-1/2 inch 4145H drill collar is a heavy-wall bottom-hole assembly component machined from quenched and tempered alloy steel for rotary drilling service. It is normally installed near the bit or inside the BHA to provide weight on bit, increase stiffness, reduce vibration and help maintain stable drilling direction.
For this shipment to King Abdulaziz Port, Dammam, Saudi Arabia, Octal Drill Pipes prepared 6-1/2 inch 4145H drill collars with project-specified bore, NC50 connections, machined shoulders and protected threaded ends. Before dispatch, the finished collars were reviewed for material identity, dimensional accuracy, hardness, thread and shoulder condition, internal clearance, marking, packing records and MTC traceability.
Order Overview
| Item | Order Details |
|---|---|
| Destination | King Abdulaziz Port, Dammam, Eastern Province, Saudi Arabia |
| Product | 6-1/2 Inch 4145H Drill Collar |
| Product Type | API 7-1 Drill Collar |
| Outside Diameter | 6-1/2 in / 165.1 mm |
| Material | AISI 4145H Modified alloy steel or approved equivalent |
| Heat Treatment | Quenched and tempered |
| Collar Type | Slick drill collar |
| Connection | NC50 |
| Bore / ID | Project-specified bore, verified by dimensional and drift review |
| Length | R2 or project-specified length |
6-1/2 Inch Drill Collar Specification Review
The designation 6-1/2 inch drill collar refers to the outside diameter of the collar body. It does not describe the complete finished tool by itself. A finished drill collar must also be reviewed by material grade, heat treatment, bore size, connection type, thread condition, shoulder quality, straightness, hardness range, marking and inspection records.
For this Saudi Arabia shipment, the 6-1/2 inch OD collar body was matched with 4145H material, quenched and tempered heat treatment, and NC50 rotary-shouldered connections. This configuration is commonly used in BHA sections where stiffness, weight concentration and connection reliability are more important than flexibility.
| Review Item | Shipment Configuration | Release Significance |
|---|---|---|
| Collar body | 6-1/2 in OD | Confirms the main drill collar size |
| Material | 4145H Modified alloy steel | Supports strength and toughness requirements |
| Heat treatment | Quenched and tempered | Controls hardness and mechanical performance |
| Bore | Project-specified ID | Confirms internal passage and drift requirement |
| Connection | NC50 | Confirms compatibility with adjacent BHA components |
| Collar type | Slick drill collar | Supports standard BHA assembly and handling |
| Documentation | MTC and inspection records | Supports receiving inspection and traceability |
4145H Material and Heat Treatment Control
The material route is one of the most important control points for a 6-1/2 inch 4145H drill collar. The collar must be tied to the correct heat number, material certificate, heat-treatment record and final inspection file before shipment release.
4145H Modified alloy steel is selected because drill collars work under high compressive load, rotation, shock and bending exposure near the bottom of the drill string. Quenching and tempering are used to achieve the required balance of strength, hardness and toughness for drilling service.
| Control Area | What Was Checked | Release Record |
|---|---|---|
| Material identity | Heat number and material grade | MTC |
| Chemical composition | Controlled alloy-steel chemistry | Material certificate |
| Heat treatment | Quench and temper route | Heat-treatment record |
| Hardness | Surface and body hardness per requirement | Hardness report |
| Mechanical performance | Strength and toughness records when required | Test report |
| Traceability | Marking matched with documents | Packing list and inspection file |
A material name alone is not enough for release. The physical collar marking, MTC, heat-treatment record, hardness record and packing list must remain consistent through the full document chain.
Drill Collar Position in the BHA
A 6-1/2 inch 4145H drill collar is normally used in the bottom-hole assembly, close to the bit or below heavy weight drill pipe. Its main function is to add concentrated weight and stiffness so the bit can drill with stable loading while the upper drill string remains more flexible.
| Drill-String Section | Structure | Function |
|---|---|---|
| Conventional drill pipe | Lighter and more flexible | Transmits torque and drilling fluid |
| Heavy weight drill pipe | Intermediate stiffness | Helps transition between drill pipe and collars |
| Drill collar | Heavy-wall and rigid | Provides weight on bit and BHA stiffness |
| Bit section | Cutting structure | Breaks formation under applied load |
In directional, vertical, milling, workover or hole-conditioning operations, drill collars help stabilize the BHA and reduce unwanted bending or vibration. The final quantity and placement depend on the drilling program and BHA design.
Dimensional and Internal-Clearance Review
Dimensional inspection for a 6-1/2 inch drill collar should cover more than outside diameter. The bore, straightness, connection position, shoulder face and finished length all affect field compatibility.
The inspection review covered:
- 6-1/2 inch outside diameter;
- project-specified bore and drift requirement;
- finished length and tally record;
- straightness and body surface condition;
- NC50 pin and box connection identity;
- rotary shoulder condition;
- bore transition and internal cleanliness;
- marking and traceability.
Internal clearance is important because downhole tools, fluid flow and inspection gauges may pass through the collar bore. A correct OD does not confirm full acceptance unless the bore and drift requirement are also reviewed.
NC50 Connection and Shoulder Inspection Before Packing
The NC50 connection was checked as a key release item before export packing. Pin and box ends must match the order and must remain protected during handling, storage and transportation.
| Inspection Area | Condition to Check | Practical Risk Controlled |
|---|---|---|
| NC50 pin thread | Burrs, dents, rolled edges or local damage | Difficult make-up or gauge rejection |
| NC50 box thread | Clean entry and complete thread form | Cross-threading or poor engagement |
| Thread flanks | Tearing, abnormal tool marks or impact damage | Uneven load transfer after make-up |
| Rotary shoulder | Raised metal, dents or embedded particles | Poor shoulder contact |
| Bore entry | Chips, steps or visible obstruction | Restricted internal passage |
| Thread protector | Correct fit and secure installation | Thread damage during shipment |
After inspection, thread protectors were installed on the pin and box ends. Protector fit was reviewed again during packing to reduce the risk of connection damage before arrival at Dammam.
Packing and Shipment to Dammam, Saudi Arabia
The shipment was prepared for delivery to King Abdulaziz Port, Dammam, Saudi Arabia. Packing control focused on protecting the machined connections, keeping the collars stable during handling, and maintaining document consistency from warehouse release to shipment handover.
The packing review confirmed:
- collar quantity and bundle identity;
- 6-1/2 inch drill collar marking;
- 4145H material traceability;
- NC50 connection identity;
- thread protector condition;
- packing list consistency;
- MTC and inspection record availability;
- shipment photo records.
For drill collar export orders, packing is also a document-control checkpoint. The released collars should match the MTC, inspection file, packing list, bundle tag and shipment records before dispatch.
Supporting 6-1/2 Inch Drill Collar Supply for Saudi Arabia Projects
This 6-1/2 inch 4145H drill collar shipment to Dammam, Saudi Arabia demonstrates Octal Drill Pipes’ ability to support BHA-related drilling tool orders where material identity, heat treatment, hardness, connection condition and packing traceability must be reviewed together.
A drill collar order is not evaluated by OD alone. The final release should confirm the collar body, bore, connection, shoulder, hardness, marking and document package. This helps reduce receiving-inspection delays and supports smoother project handover after arrival at destination.
FAQ
F1:What is a drill collar used for in a BHA?
Q1:A drill collar is a heavy-wall drill-stem component installed near the bit to provide weight on bit, increase lower BHA stiffness, reduce vibration, and help maintain drilling direction. It is more rigid than standard drill pipe and is selected by OD, bore, connection and BHA design.
F2:What should be checked on a drill collar connection before shipment?
Q2:The connection check should cover pin and box thread condition, rotary shoulder surface, bore entry, thread flank damage, gauge acceptance where required, and protector fit. For NC50 or other rotary-shouldered connections, shoulder condition is especially important because it affects make-up contact and load transfer.
F3:What documents should be included for a drill collar shipment to Saudi Arabia?
Q3:A drill collar shipment file should include MTC, heat-treatment record, hardness report, dimensional inspection, NC50 thread inspection, NDT or MPI record when required, packing list, bundle marking and shipment photos for traceability at destination.
F4:What documents should be included with a drill collar shipment?
Q4:A drill collar shipment file should include MTC, heat-treatment record, hardness report, dimensional inspection, thread inspection, UT or MPI record when required, packing list, bundle marking and shipment photos. These records link the physical collars to material identity, inspection status and final release traceability.
