Heavy Weight Drill Pipe (HDWP)

Introduction:

Heavy weight drill pipe has a “center upset”, also known as wear pad, that increases tube life by protecting the tube from wearing on the outer diameter by keeping the tube away from the hole wall. It also reduces hole drag and differential sticking problems. The walls of heavy weight drill pipe are thicker and have longer upsets compared to conventional drill pipe, as well as being stronger with high tensile strength.

Application:

Heavy weight drill pipe (HWDP) is usually run in between the drill collars and the drill pipe in order to prevent fatigue of the drill pipe in the vertical drilling industry. Heavy weight drill pipe is also utilized in the horizontal directional drilling (HDD) industry for added strength in high stress situations. Heavy weight drill pipe (HWDP) may be used to make the transition between the drill collars and drill pipe. The function of the HWDP is to provide a flexible transition between the drill collars and the drill pipe.

Quality Standard:

• API 7 Specification for Rotary Drill Stem Elements
• API 5DP Specification for Drill Pipe

Steel Grade:

• Integral HWDP : AISI 4145HM
• Welded HWDP : AISI 1340 pipe body, AISI 4140HM tool joint

Sizes Range:

• Outer Diameter: 2 7/8” – 6 5/8”
• Weight Range:   6.27#/FT through 27.72#/FT
• Lengths:   Range 2 and Range 3
• End Finishes:   Internal Upset, External Upset, Plain End Upset, Non Upset
• Tool Joint type：NC38、NC46、NC50、5-1/2 FH

Feature:

• A. High precision in size and shape
• B. Good low temperature toughness
• C. Excellent comprehensive mechanical properties
• D. High connection strength and sealability
• E. Large inside diameter of tool joint
• F. High  torque resistance
• G. High fatigue strength and long fatigue life

 Internal Coating Feature:

• A.High abrasion resistance and low friction factor
• B. Good adhesion and flexility
• C. High application temperature and pressure
• D. High hardness and impact resistance
• E. Good corrosion resistance

Hardbanding Feature:

• A. Good balance between antiwear and friction-reduction
• B. The wear rate is less than 6% of that of bare tool joint, which can prolong 3 times of the tool joint service life
• C. Good property of friction-reduction, which can reduce the casing wear to the least, and its wear to casing is less than 11% of that of bare tool joint
• D. Reduce the torque of drilling string
• E. Good weldablity with little splash and good rewelding preformance
• F. Friendly to environment

Options:

1. Internal Plastic Coating
2. Hardband Type especially on box and pin tool joint
3. Proprietary Connections
4. Make and Break Test

Mill Test Certificates:

1. Issued in accordance with API Spec 7/7-1 and API RP7G .
2. Third Party Inspection can be performed on request at buyer’s care and expense.

Recommendations for running heavy weight drill pipe:

When run in vertical holes for weight:

1. Run the necessary number of joints to provide the required weight plus enough more joints to ensure the transition point stays in the heavy weight pipe.

2.Do not run in compression where the hole size is more than 4″ larger than the heavy weight tool joint size.

When run in the transition zone between pipe and collars:

1. Run a minimum of 18 to 21 joints.

2. Utilize the manufacturer’s recommendations for the maximum drill collar size to be run below the heavy weight.

When run in directional holes for weight:

1. Run the necessary number of joints to achieve the desired weight on bit. (It is not uncommon to run as many as 60 joints in this application.)