Secoroc Tubes for DTH Drilling

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2020年12月13日

2 3/8" Failing Exploration Thread Fedp Drill Pipe for Water Well Drilling

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Drill Pipe Selection Guide
















Drill pipe is hollow, thick-walled piping that transmits drilling fluid and torque through the wellbore to the drill bit on a drilling rig. It is manufactured to withstand severe internal and external pressure, distortion, bending, and vibration as it both rotates and lifts the bottom hole assembly (BHA). Drill pipe is threaded on each end in a section of pipe referred to as the tool joint. It is manufactured, sampled, tested, and inspected in accordance with standard specifications such as the American Petroleum Institute (API).Drill Pipe Selection Guide


Types

Standard drill pipes are long tubular sections of pipe that make up the majority of the drill string. They are typically a 31 foot long section of tubular pipe but may be anywhere from 18 to 45 feet in length.


Heavy weight drill pipe (HWDP) is a tubular pipe that adds weight or acts as a transitional piece in the drill string. As a transitional section of the drill string, it is placed between the drill collar and standard drill pipe to reduce fatigue failures. In other applications the HWDP is used as an additional weight to weigh down the drill string.


Drill collars are a component of the drill string that makes up part of the BHA. They are thicker-walled, heavier, and more rigid than drill pipes and are primarily used to weigh down the drill bit while dampening vibration and impact forces.





Drill Pipe


No Weak Links

Traditionally the threads and the joint between the tube and the end-pieces are vulnerable. To combat the problem we've friction-welded the joints for maximum strength and heat-treated the end-pieces for optimum durability.




Secoroc Tubes -- Part of a Productive Package

Though their importance is often underestimated, tubes play an important role in DTH drilling -- regardless of application, rock type, hole depth, or drill rig. The key features of a high quality DTH tube are durability, accuracy, and manageability.



High Quality Tubing

Secoroc tubes are made from cold drawn tubing, providing a superior surface finish and tolerance compared to their hot-rolled counterparts. Our solution drastically reduces the risk of scaling -- the cause of so many premature hammer failures.


Never Losing the Thread

Heat-treating the threads ensures not only a long service life, but also simplifies joining and breaking -- thereby cutting cycle time. To meet varying demands, we provide a selection of API threads. For applications where foam injection are used, we recommend the IF thread. Naturally, we also offer a wide range of subs and crossovers -- all made of high quality steel and heat-treated in the same way as tube end-pieces.



Pipes From 4-1/2" and Wall Thickness >0.346"

Hot Rolled Grade API J-55


Technical Spec:

Tubing J-55Tool Joints, Adapters
Tensile Strength (RM) min.75,000 PSISurface Hardness58-62 HRC
Yield Strength (ReH) min.55,000 PSIDepth0.080"
Elongation (A5) min.15%Core Hardness32-36 HRC (approx. 300 HB)



Hot rolled tubing fits inside the API N-80 standard, but it has the following shortcomings:

. The hot rolled surface is rough and can release scaling from the inside, which can enter into the hammer and cause severe damage to internal components.

. A rough surface gives higher friction losses, resulting in a higher pressure drop in the drill string.

. Wide tolerance of the wall thickness +/- 10-12%.

. Straightness tolerance not assigned. Must be straightened after welding.

. Production problems due to wide tolerances.




Pipes From 2-3/4" to 4-1/2" and Wall Thickness >0.346"

Hot Rolled Grade API J-55


Technical Spec:

Tubing N-80Tool Joints, Adapters
Tensile Strength (RM) min.100,000 PSISurface Hardness58-62 HRC
Yield Strength (ReH) min.80,000 PSIDepth0.080"
Elongation (A5) min.18%Core Hardness32-36 HRC (approx. 300 HB)


In order to improve the quality of DTH tubes we are now changing over to cold drawn tubing, and the features and benefits are as follows:


FeatureHot Rolled TubingCold Drawn Tubing
OvalityIncluded in the tolerance for the wallIncluded in the tolerance for the wall
Wall Thickness+/- 10-12%+/- 3-4%
StraightnessN/A0.012"/ft



Benefits in Short of Cold Drawn Tubing:

. Reliable wall thickness

. Less ovality, less risk of eccentric wear

. Better quality of the friction weld, less risk of concentricity of welding

. Better wear resistance due to increased hardness

. Reliable weights max 2-3% variance

. Less risk of damage to the tube from the straightening operation

. An overall weight reduction of our DTH tube assortment

. Still API N-80 standard for tubing




Friction Welding 2-3/4" to 5-1/2" ---- Over 5-1/2" Shrink Fit and Stick Welded




Friction Welding:

. Friction welding is a safe and efficient way to weld the end-pieces on to the tube material. The welding becomes stronger than the tube.

. Friction welding is a combination between friction and pressure.

. The end-pieces rotate with a speed of 480 RPM, and the pressure is between 1,015 PSI and 2,175 PSI depending on the tube diameter and wall thickness.



Friction Welded:

. Friction welding gives much stronger joints, compared with electrode welding, due to less risk of impure joints.





Rotary HeadThe power unit that rotates the drill string.
Spindle AdapterAlso called a "saver sub," threads into the rotary head and drill pipe, protects the threads of the rotary head, considered to be part of rotary head.
Drill PipeAvailable in a variety of lengths, diameters, wall thicknesses, and thread configurations.
Starter PipeSimilar to the drill pipe, always the first pipe in the hole, usually shorter to compensate for the length of the DTH hammer, and with a greater wall thickness to withstand more abrasion as the hole is drilled.
Sub AdapterUsually a short adapter, threaded on both ends in a male/female, female/female, male/male configuration. May be used to increase or decrease the thread diameter or change the thread style as needed for a particular application.
DHT Hammer/ DTH BitThe percussive mechanism that drills the hole. Available in a wide range of diameters and styles depending on the application.
Rotary (Tricone) BitMay take the place of the DTH Hammer and Bit in applications where percussive drilling is not required.


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