Ton Miles

Replies to This Discussion

Permalink Reply by Wayne Nash on June 13, 2011 at 8:42pm

I have found that the reserve spool lasts longest with frequent, short slip & cuts. Long intervals take long cuts, but the weak point is the 'pick-up' points, thus increasing the possibility of failure.

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Permalink Reply by Sergei Tchernenkov on June 19, 2011 at 2:40pm

It will depend on the type and size of the drill line cable, and your question is answered by API RP 9B.

However, the simplified answer for generic drill line can be found in the table at the page F24 in the "Green Book" - Drilling Data Handbook, Section F.

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Permalink Reply by sonny crumb on June 19, 2011 at 7:25pm

2800 ton miles is the maximum that we run on our rig.

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Permalink Reply by micheal martin on July 30, 2011 at 8:32pm

thats alot

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Permalink Reply by micheal martin on July 30, 2011 at 8:32pm

what size line

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Permalink Reply by DP Consultant on July 17, 2011 at 6:29pm

Not exactly answering the question, but I saw a really interesting use of technology.  I flew with the CEO of Huisman of Holland.  He said on large floaters they built drawworks with larger than normal drums, and instead of a deadline anchor used another identical drawworks.  This gives you a redundant drawworks, which is clever by itself, but he also claimed that by monitoring  hook position they could spool the two drawworks in and out as needed to distribute ton miles along the rope.  He claimed their modeling showed they could achieve a 20 YEAR drilling line life!  I challenged him on that, and he said he could prove it, but I didn't check his math.  I did ask how, and he said there is enough straight section in the wire path on a floater that you could cycle one section of rope, then move it to where it was mostly in the straight path crown to drum (they also mount the drawworks 50 feet below the drill floor to reduce noise).  He also said that because they calculate the load and bend of the entire active parts of rope at the same time, they use actual ton miles AT EACH POINT ALONG THE ROPE rather than overall average.  Even if it did 5 years, that's impressive use of technology.  Of course, what makes economic sense on a dual activity 720K/day floater won't on something like a land rig, but you could use the same technology on a smaller scale to more precisely track actual wear, and help plan the slip/cut program.

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Permalink Reply by Milkshake Drinker on July 20, 2011 at 3:50pm

That setup can replace this type of deadline anchor?

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Permalink Reply by Mujahid Khalil Awaad on July 21, 2011 at 10:48am

we run 2100 ton miles to cut & slip and this for all our offshore rigs with different type of drawworks and top drive even Kelly

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Permalink Reply by Tracy Wilson on September 6, 2011 at 4:21pm

Regardless of your rigs goal visual inspection overrides all other aspects. Is the line broken, flattened? How many busted strands. This among other things determines your rigs goal. I worked on a rig so small that there was no way to cut on ton miles. The line was worn smooth out long before you accumulated enough miles to cut. We just kept our eyes on it and cut about every couple of wells.

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Permalink Reply by Tex on November 24, 2011 at 3:43pm

If anyone can give you a direct #### answer to this question then I can assure you
they are wrong. On most rigs using 1-1/2" or 1-5/8" drill line the
standard is going to be between 2700 and 3000 Ton miles. This is when all
calculations are done by hand as when the driller or T/P are calculating the
trips (weights and distance lifted) and work done using a T/M spread sheet etc.
There are as stated many variables in this process. All rigs are not the same.
Draw-works drum circumference and also block//crown sheave circumference will
have a great effect on line wear. Condition of the drum grooving on the
draw-works and fleet angle of the drill line from the crown to the kick-off
rollers of the draw-works have an effect, the wear plate condition at the edge of
the drum (are they worn which causes line damage) and does your second and
third layer wrap back perfectly as the drill line starts the next layer? Are
you drilling in the south or up north in hard rock country?

Most of these questions all have purpose and on the other hand have none at all. If
you actually had a computerized T/M counter you might find that in reality you
were really cutting at 3700 or 4100 Ton miles. Blocks are moved all the time
without being recorded. Drilling with stands and picking up singles from the
mousehole, working off of a stabbing board, so many variables are not
considered.

What does work is this. Rig history and being consistent as possible between crews
when it comes to keeping important data and information such as T/Miles. If one
crew fails to keep proper records the next crew may pay the price and it can be
a high price to pay.

Two rigs running the exact same drill line from the same manufacturer may not
achieve the same T/mile record because of the variables mentioned above.
Periodic drill line inspections should be carried out looking for broken
strands, flattened strands, distorted (out of round) drill line or
under-calipered drill line. Most drill line failures will occur naturally
closer to the fast line side of the reeve. First or second layer of the
draw-works drum, this is the oldest line and has the most actual ton miles on
it. Let’s just say your total string up is 1200 feet of cable. Each cut you
make is 100 feet. You have to achieve 12 slip and cuts to have the new line
from the first cut reach the draw-works. Always inspect the wire which is on
the first layer of the drum plus the kick off point starting the second layer.
Periodically check this drill line with a caliper (micrometer) to see if it is
still the proper diameter. If inner core is failing then the over-all diameter
will be less than normal. 

Sometimes rigs do get into an accepted slip and cut program from trial and error which
really is wise and cost-effective and in this case people are not asking the
question (how many T/M can you run before slipping and cutting?) If you are
slipping and cutting constantly and consistently at 2800 T/M and never have to
make a long cut then for sure you are either running at or below the possible
achievable T/Miles. On the other hand if that line you are cutting is not
flattened or contain any broken strands then it is possible that you could
actually extend your T/Ms to 2900 or 3000. But be cautious because there is a
point which can be passed which will show up a few cuts 3 or 4 down the line
where you will see damage to the drill line and you might have to cut 200 to
400 ft of drill line to get rid of the bad line and then drop back on your
T/Miles once again to prevent a repeat. Each rig is different, time, study and
good history will only really answer your question properly.

 

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Permalink Reply by Curtis alpha on January 23, 2012 at 1:51am

I don't know the max. Our company requires we slip and cut every 1200 ton miles

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Permalink Reply by Dustin Frazier on January 23, 2012 at 11:28pm

We slip and cut around 1300 to 1600, depends on where we are at, we just got a new dw. Our old dw we were slipping at a max of 1300 which was prob a little long because everything was wore out on it, it ate line like you would not believe. This is on 10 lines of 1 1/8, but our new dw with everything new, the line still looks new when we slip and cut at 1600, so we might be gonna try and bump up our goal. Like Tracy said, visual inspection over rides it all though. I never even knew how to keep ton miles until I got my pushing job, my pushers always had me slip and cut by visually inspecting it. I don't know if they didn't know how to keep tons miles or just didn't want to but I was never told how much to slip and cut as a driller.

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