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Abnormal Torque with increasing RPM upto 150
03 June 2020
During drilling a vertical 8½" well-bore with rotary BHA, while increasing the RPM from 120 to 150, the drilling torque will increase abnormally more than 10 klb-ft in open hole.

However, we have to check  the torque in 9⅝" csg and the same results happened in the cased hole. what is the most possible reason for this case.

Is this a problem with Topdrive bearing?

Thanks

8 answer(s)
SimonKlampfer
Senior Advisor Well Engineering Global Skillpool
OMV
Total Posts: 4
Join Date: 25/12/15
Hi Sina,
I ran across a similar problem quite some 20 years ago , trying to mill a production packer - excessive torque off bottom limited us to 70 RPM - string did no show any vibration, no wear pattern on the string (like polished spots on the tooljoints or pipe, hole was vertical, tortuosity could not be assessed because of lack of sufficient surveys). Unfortunately we did not dig deeper, but honestly (this may sound stupid anyway) I thought that by magnetic interference we were running a generator downhole (rotating pipe in a magnetic field) and thereby getting these torque readings.
Stebbings@btconnect.
Wellsite
SPREAD Associates
Total Posts: 3
Join Date: 15/08/17
Hi Sina,

You mention Vertical well.
Rotary drilling assy
Torque in the casing and in OH?
Are you tripping in or out
Are you drilling
What is your mudweight and lubricity
How are you maintaining verticality ? DD tools?
What modes are you tripping in hole with - with your rotary drilling tools.

Get hold of the raw directional survey files (not averaged over 30m / 90 ft)) for a high local dogleg in the cased hole interval.  Find locate the bit depth where you encounter this.

Check topdrive alignment to the hole Rotary table - verticality and offsets. 

Any - Torque and drag modeling conducted?

If you find DLS > 3.5 degs instantaneous in the casing - run a CSG wall thickness and wear log (USIT 2MHz log) - potentially worn casing or collapsed casing causing additional string rotational stick-slip behaviors.

What are the formations you are have drilled through in the previous hole section (any formation mobility) that may have caused casing ovalisation?  Ie the problem might not be your drillstring but the last casing string. 

learning.lifewayne@g
D&C Project Coordinator / Decommissioning
SPREAD Associates
Total Posts: 35
Join Date: 25/01/16
Lots of good points.  Drill string harmonics for sure and what is the azimuth and inclination change per 100 ft.  Spiraliing causes so many T&D problems and it all goes to the top drive. Time to put a drilling engineer into the mud logging unit.
learning.lifewayne@g
D&C Project Coordinator / Decommissioning
SPREAD Associates
Total Posts: 35
Join Date: 25/01/16
Lots of good points.  Drill string harmonics for sure and what is the azimuth and inclination change per 100 ft.  Spiraliing causes so many T&D problems and it all goes to the top drive. Time to put a drilling engineer into the mud logging unit.
Companyrep
Drilling Specialist/Well Engineer/Training Consultant
Kingdom Drilling
Total Posts: 462
Join Date: 10/01/05

You have 10k of Physical torque and evident reasons that  states you have an issue. 

Where this is emanating from is likely the well not the top drive. 

As it should overheat or something ( ie thrust bearing) etc will quickly fail under this type of abnormal load I’d my view.

Run a surface tests then a similar test after BHA has been run.

Then check torque and drag  trends every 10 stand to give us a pattern of evidence to work with. 

Is this simply a higher consistent torque you are observing. 

Is your drag higher than normal ( vs. Expected string weight in mud?) 

Or is it a variant fluctuation torque?.
By Hoo much?

What exactly are the numbers you are observing at TD depth and at the shoe? 

As stated by other do something tests at different RPMs and collect the evident data. 

What does your torque drag model state? based on survey data?

When you trip out from the shoe unlock the swivel are you observing the string turning anti clockwork wise as you pull out of hole more than normal? . Again all indicators may be poor wellbore cylindricity and: or cased hole quality issues? If you onbserve same effect in open and cases hole. That could be the source of abnormalities of what you are observing?  

if you don’t have surveys . You could drop a multi shot on trip out from casing shoe on next bha trip out? Then run your torque drag model based on results obtained. 

What steel are you getting back from the shaker at the magnets? This could be indicative of wellbore tortuously?

Are you collecting the steel and measuring casing wear daily during drilling? 
How much are you observing? 

Because You could have a spiralled doglegged casing is your well pointing to the reason for your discrepancies. 

Was the last casing properly centralised?. 

Mud type? Solids content? Eg Silicate mud will give you extremely higher torque in even a vertical well in 81/2 in hole vs  previous 12 1/4 in section.

Torque and drag tests as stated should show a trend to indicate it may be a mud problem if you are not seeing still at shakers etc.,  

All suggestions of how to further investigate your evident problem. 

Finally when was the last time the torque gauge was calibrated and checked? I would get the mechanic to verify this is also not the problem. 




Boumezrag
Drilling supervisor
Sonatrach Petroleum Corporation
Total Posts: 11
Join Date: 11/02/16
Hello Sina;
I would think about drill string vibrations, especially lateral ones.
You can imagine the drill string as rope fixed in two parts and you rotate with high speed; that would inevitably cause a large contact surface of DP tool joints and statabilizers in the well bore or the casing.

Best Regads;
Mohamed Boumezrag
IainDD
Lead ERD Advisor / Engineer / Instructor
Merlin ERD Limited
Total Posts: 15
Join Date: 04/05/16
What depth are you at? You could possibly be initiating whirl in the drill pipe as you step up the RPM. How does the torque react at 130 and 140 RPM. If the drill string is in whirl you have more contact with the well bore, more contact = increase in torque.

1vartecheng
Managing Director
Vartech Eng
Total Posts: 21
Join Date: 06/07/15
Hi Sina Zamani,

Any other potential source of extra torque such as Tooljoint size of the drill string, junk in hole, size of the BHA components (i.e. Gauge stabilzers), change of drilling fluid?

Thanks
Reynaldo Vargas
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