Guidelines for installing, maintaining and cutting drill lines properly.

 

Proper installation of drill lines can be performed using these three steps:

1. Use a “snake” with a swivel to connect the new drill line to the old drill line. This will relieve twist that may be put in the rope during spooling and handling. Important: Never weld the new drill line to the old drill line so that twist is not transferred from the old line to the new one.

2. Try to install the new drill line at a point in the drilling operation where there’s a considerable amount of weight available to help seat or “break in” the new drill line and assist in spooling. Drill lines are made approximately 4% over the nominal size. Some lagging is 2-1/2% over the nominal rope size. This can cause a spooling problem of the rope not fitting in the lagging. By having a high load on the rope, it normally pulls down and fits in the lagging.

3. Check the brass inserts on the dead line anchor for proper size. If worn or damaged, replace. Make sure they’re properly installed and tightened. After the first one or two hours of operation, the torque should be rechecked.

Follow our cut-off program for longer service life.

It has been proven that the service life of drilling lines can be dramatically increased by following 
a planned cut-off program based upon work performed by the rope. This moves the rope through the system so the wear can be spread uniformly along the entire length of the rope. As the rope is cut off the drum end, new rope is slipped into the system, on the dead line side, thereby extending the service life of drilling lines.

We offer the tools needed to calculate the amount of work performed by the drilling line to permit cutting at the proper times. With these calculations, we can help determine the rate at which rope is moved through the system.

Our cut-off program is not designed to replace visual inspection. In all cases, visual inspection of the wire rope by the drilling contractor must prevail over any calculations made. 

For years, we’ve offered a manual cut-off program for drilling lines featuring a Union Wire Rope Ton-Mile Indicator. For complete details — including calculation instructions — please refer to our “Cut-Off Practice for Rotary Drilling” or our computerized system available on CD-ROM. 

A thorough inspection program must be used in conjunction with any cut-off program.

Guidelines to help prevent long cuts.

Anytime the amount of rope to be cut doesn’t remove all of the rope that meets the removal criteria, a “long cut” is necessary. The most common causes of a long cut are:

– Failure to follow the ton-mile goal.
– Improper calculations or recording of your rope’s ton-miles.
– Damage at any point of the rope, requiring a long cut.

If no long cuts are required, and it is believed a line can provide more service, the goal can be raised one ton-mile per foot cut. This procedure should be followed until the optimum goal is found.

To prevent long cuts, we recommend the following three practices:

1. Find the optimal ton-mile goal for your wire rope. Experience may indicate you have to change your ton-mile goal. It’s important to follow the cut-off program with a new rope. The first few cuts may appear to be removing rope that doesn’t meet the rope removal criteria. This is necessary to move all the rope through the system at the proper rate.

2. Ton-miles must be calculated and recorded accurately for each operation.

3. Equipment inspections are also important to prevent conditions that may have a detrimental effect on rope service life. Equipment problems such as a bearing failure in a sheave can also cause unusual rope wear, leading to long cuts. 

The objective to any wire rope cut-off program is this: move the drill line through the system so wear is distributed, enabling the line to be removed from the drum end when it has just reached the end of its useful service life.

 

Make the most of your wire rope through regular inspections.

 

Despite their durability and strength, wire ropes will eventually wear out and must be removed after a period of use. That’s why regular inspection is crucial.

How often to inspect.

All hoisting lines should be visually inspected at least once each day when in use, as suggested by American Petroleum Institute (API) RP54 guidelines. Hoisting lines should be thoroughly inspected once each month and a record made of the monthly inspection.

Any wire ropes that have met the following criteria for removal must be immediately replaced. When in doubt, replace. The cost is minimal compared to what could happen if your rope breaks. 

When to replace running ropes due to broken wires.

Wire ropes used as running ropes other than sand lines should be removed from service when broken wires meet any of the following criteria:

– For six- and eight-strand constructions, replace when you see six randomly distributed broken wires within one lay length, or three broken wires in one strand within one lay length.

– For rotation-resistant constructions, replace when you see two randomly distributed broken wires in six rope diameters — or four randomly distributed broken wires in 30 rope diameters.

Sand lines should be removed from service when you see three broken wires within one lay length.

When to replace standing ropes due to broken wires.

Wire ropes used as standing ropes such as guy lines, escape lines and pendant lines should be removed from service when any of the following conditions exist:

– Three broken wires are found within one lay length.
– More than one broken wire is found at the end connection.
– Broken wires are found in the valleys between the rope’s strands.

Other reasons to replace ropes.

Broken wires are only one way wire ropes wear out. Other conditions for removal 
of wire rope from service are:

– Corrosion that pits the wires.
– Corroded wires at end connections.
– End connections that are corroded, cracked, bent, worn or improperly applied.
– Evidence of kinking, crushing, cutting, bird-caging or a popped core.
– Wear that exceeds one-third of a wire’s original diameter.
– Severe reduction of the rope’s diameter.
– Evidence of heat damage.
– A significant increase in lay length.

How to find broken wires.

One of the most common signs of rope deterioration is broken wires, normally the outside wires on the crowns of the strands. 

Running ropes: Because of their contact with sheaves and drums, running ropes typically receive heavier external wear than standing ropes. This can result in surface wire breaks — the easiest kind to locate during your inspection. The challenge is to find valley wire breaks. These may occur when ropes are used with small diameter sheaves, sheave grooves that are too small, heavy loads and other poor operating conditions. During your inspection, pay close attention to the areas of the rope in contact with sheaves and drums when loads are picked up. If there is a reason to suspect valley wire breaks, such as a reduction in rope diameter or elongation of rope lay, perform an inspection as outlined below for standing ropes.

Standing ropes: Most wire breaks in standing ropes are internal (or valley) breaks that occur at the points of wire contact. Inspection will reveal no surface wear and therefore nothing to cause external wire breaks. The majority of broken wire problems on standing ropes occur near the end attachments or other points of restriction where vibration is damped.

 

Typical crown and valley wire breaks in outer wires.

 

Follow these steps to inspect for valley breaks: 

1. The first step is to relax your rope to a stationary position and move the pick-up points off the sheaves. Clean the surface of the rope with a cloth — a wire brush, if necessary — so you can see any breaks.

2. Flex the rope to expose any broken wires hidden in the valleys between the strands. 

3. Visually check for any broken wires. One way to check for crown breaks is to run a cloth along the rope to check for possible snags.

 
4. With an awl, probe between wires and strands and lift any wires that appear loose. Evidence of internal broken wires may require a more extensive rope examination.

For additional information and requirements, please refer to the latest edition of: 

– API RP 2D: Recommended Practice for Operation and Maintenance of Offshore Cranes
– API RP 9B: Recommended Practice on Application, Care and Use of Wire Rope for Oilfield Service
– API RP 54: Recommended Practices for Occupational Safety for Oil and Gas Well Drilling and Servicing Operations
– ASME B30.5: Mobile and Locomotive Cranes (crane rope removal criteria)