OCTG – Drill Pipe

• ​Introduction

Drill pipe is a key component of oil and gas drilling equipment, serving as a hollow steel pipe that connects the surface drilling rig to the drill bit at the bottom of the well. It forms the main channel for transmitting mechanical power, circulating drilling fluids, and conveying downhole measurement data. As the primary tool for deep subsurface exploration, its reliability directly affects drilling efficiency and safety.

• ​Main Functions

Transmitting Torque：Transmits the rotational force from the surface rig to the drill bit, enabling rock breaking and wellbore formation.

Circulating Drilling Fluids：Provides a passage for drilling fluids to flow downward from the surface to the well bottom, carrying cuttings back to the surface and cooling the drill bit.

Supporting Downhole Tools：Supports and connects downhole tools (e.g., motors, measurement instruments), forming a complete downhole system.

Withstanding Complex Loads：Bears axial loads (tension/compression), torsional forces, and lateral stresses during drilling, ensuring structural integrity in harsh downhole environments.

• ​TubingStandards

ISO 11961；API Spec 5DP；GB/T 29166-2021

• ​Material & Performance

Gr. E75, X95, G105, S135,SS95,SS105

Tensile Strength: The maximum axial load the pipe can withstand without fracture. Yield Strength: The stress at which permanent deformation begins. Torsional Strength: Resistance to twisting forces during drilling. Corrosion Resistance: Ability to withstand harsh media (e.g., H₂S, CO₂) in downhole fluids.

• ​Manufacturing Process

Pipe Body Production： Raw Material Preparation: Hot-rolling seamless steel tubes from alloy steel billets. Heat Treatment: Quenching and tempering to achieve target mechanical properties. Thread Machining: Cutting API-standard or premium threads at both ends of the pipe.

Tool Joint Production： Forging high-strength alloy steel into tool joints, followed by heat treatment and thread machining.

Assembly and Welding： Using friction welding or upset butt welding to join the pipe body and tool joints, ensuring coaxiality and weld integrity.

Testing and Inspection： Non-Destructive Testing (NDT): Magnetic particle inspection, ultrasonic testing to detect defects. Hydrostatic Testing: Pressurizing the pipe with water to verify leak-tightness and structural strength. Dimensional and Thread Inspection: Ensuring compliance with standards.

• Specifications