Private Forums
Managing of overpull issues/the best drilling practices
08 July 2019
Dear forum members I have 3 questions with regard to modern drilling practices: 1.Wiper trips practices We are trying to avoid excessive wiper and check trips when there is no need for one in our local land operations in Ukraine. In the past we would do check trips every 200m regardless of the hole conditions. However we understand that at some point we have to do check trips, for instance when there are excessive overpulls or before running the casing or wireline etc. We would like to hear what are your practices for wiper trips? When do you normally decide to do one? Are there any numbers you are guided by, like overpulls? 2. Connections practice We also would like to hear what connection practices are you generally applying in your operations and why. For reference, we drill one stand and wipe the hole up and down once to the distance of one drill pipe while circulating cuttings above BHA. We try not to backream to avoid shale breakouts upper in the hole. 3. Backreaming What is your practice for backreaming? Are you trying to avoid it whenever possible or not and why. I understand much will depend on local geological conditions but still would like to hear your general approaches. Appreciate your thoughts. Regards Denys
4 answer(s)
Denir
Drilling
DTEK Oil&Gas
Total Posts: 4
Join Date: 20/06/19
Thank you gentlemen for taking the time to support and share your experience
Companyrep
Drilling Specialist/Well Engineer/Training Consultant
Kingdom Drilling
Total Posts: 389
Join Date: 10/01/05
To support Ian’s comments.

Drilling's primary purpose is to plan design engineer and assure the delivery of ‘ as near perfect wellbore cylinders’ ALARP to avoid wellbore problems and associated failings that can otherwise result. 

There is a lot however to consider to achieve this, with many multidisciplinary facets and people skills needed that are central and key to optimal and loss/waste free, connection, backreaming and wiper trip problem/failure poor practice avoidance.

However if we do the right things and get things right first time?

1. When picking up the bit and bha off bottom with normal drag observed and (well type, situations, conditions dependent) we preferably stop or  slow rotation, pick up 15ft -20ft  off bottom, sometimes more, then slack off to verify normal down weight, to then set slips, stop pumps etc and make a connection and get drilling within 5-7mins

A principled 'SEE' optimal drilling/wellbore process is EVIDENTLY working?

When we deviate from delivering SEE outcomes and benefits. We are forem most missing ALL the evident failure warning signs that exist and are precursors to wellbore and operating difficulties that can then result. So a lesson in all of this is a vigilance to address evident warning signs sooner vs later.

2. One drills the section with normal 5-7mins** (**MODU, top drive, typical offshore well) connections, with normal drag throughout is the expected goal when we do the right things and get things right first time?. 

Through more hazardous intervals we may have to change practices some what eg through interbedded sequence etc, Geology always plays a huge part.  Where we as drillers need to better understand and appreciate all the fundamental aspects to assure safer operational success.! Taking a TOFOS and conducting a dynamic risk assessment often needs to result when drilling, connecting, tripping etc. Well's section rarely drill the same.

If we commend and correct well throughout the drilling processes very few failure / problem issues shall result during connections sndf trips as per an expected norm. 
The probability of a wiper trip then is extremely low

As Ian states and personally, wiper trips are rare today notably due to advancement and use of all bit/bha systems approach, muds, mwd/lwd downhole technologies, and best practices that exist to assure and afford 'near perfect wellbore cylinders' delivery.
 
With what’s available it is surely never been easier to drill a well and poh on elevators only! If all involved do things right and get things right first time.

3. Should Wellbore Problems / failure issues result during drilling, connections, tripping, then we have all missed the evident warning signs of failings resulting. 

Note: That must be quickly and properly diagnosed and corrected with prevention always preferred too more painful cures. 

So picking up on the evident early signs and indicators always present is central and key! With all the real time big data, ROC's etc, we have today, preventing resultant wellbore failings has never been easier.

The main issue we SEE however is that people don’t adopt a loss control RAIDERS approach to wellbore failures as they manifest themselves. Failure too often accepted as a 'same as standard norm'. We also are quick to point fingers and blame the nearest persons involved vs let the wells evidence lead us to the truth of all such matters. Another discussion for another day.

4. Backreaming for example is more often prescribed without due and diligent diagnosis. In general this approach can, not always, be far be far more operationally damaging to wells, hole cleaning, tools and equipment than beneficial,  so be cautious. 

If diagnosis merits this ‘get out of jail’ option due to failings that are evidently at play? Then we employ this method as a last resort to get out of a 'failing wellbore section'. This approach takes far more time hassle and difficulties than simply poh on elevators! Prevention of this practice the preferred approach and assurance to try and assure to deliver and sustain 'near perect wellbore cylinders' ALARP.

To support all of the above we can provide 'like for like wells' that have spent days/weeks making 45mins connections, endless wiper trips and backreaming repeatedly. 

Then with wellbore failures/failings identified and resolved, these sasme wells drilled with few problems/failures. 5-7mins connections, no wiper trips, POH on elevators only. 

Rest assured ‘best in class' perfect cylindrical wells’ ALARP demand a lot of multidisciplinary skills, knowledge and wider skill sets of people made of the right stuff, in the office and the rig site.  All must be 'well' aligned planned and organized with common goals and buy in to deliver wells value at SEE outcomes and benefits desired.

S Safe (in control of all loss/waste issues)
E Effective (doing all the right things)
E Efficient (getting things right first time, every time).

Wishing you sucess in attaining future SEE wells drilling delivery.    
elman
SDE
BP
Total Posts: 20
Join Date: 01/09/12
You don't say better than Iain, so I will just second all below said. That's the point we have arrived now after a few years of trials.
IainDD
Lead ERD Advisor
Merlin ERD Limited
Total Posts: 9
Join Date: 04/05/16
Denys,

a few quick notes to your question

1.      Wiper Trips – tend not to do these. Actually, can’t remember when I last did one. A wiper trip over 200m gives you a false sense of security as it only checks that 200m of hole. So if you are going to plan on doing one you really need to trip over the full open hole to check its condition. Better option is to use good hole cleaning practises, monitor your drag, and adjust you drilling parameters / mud rheology to optimise your hole cleaning and remove the need for any sort of wiper trip. Are you monitoring your torque and drag? Are you plotting your actual against theoretical real time? This will give you an indication of a developing problem and then you can react before it gets out of control. The wiper trip was a band aid to another disfunction.

2.      Connection practices – I tend to refrain from extensive reaming at connections unless my drag measurements indicate I need to do otherwise. As a starting point look to clear your cuttings from around the collared BHA, also make sure you have freedom of movement around setting your slips. Overall that tends to be working half a single, if that. Then you are taking weights to monitor your torque and drag and then into connection. Make sure you keep the parameters up whilst you are doing any sort of back reaming – drilling flow and RPM. If drag in the well is showing signs of increasing, you may decide to ream a joint or more. But you would also want to be investigating why the drag is increasing. Have you drilled into a new formation? Has the efficiency of removing cuttings from the hole decreased? You may just have to ream a little bit more at connections to allow for some catch-up in hole cleaning.

3.      Back-reaming – not something you do lightly, but definitely something that needs to be planned for under certain circumstances.

Couple of points of note when back-reaming:

a.      Don’t expect to be able to do it quickly

b.      You need to be back-reaming with parameters that will lift your cuttings out of the well as you are going to be lifting anything that is moveable – as such you are looking at possibly the same parameters that you were drilling with. You may be able to go lower on the RPM but there are minimal limits depending on hole size (>120 in 9 7/8” and above, >100 in smaller hole sizes). Monitor your torque, pressure and hookload like a hawk, and be ready to react accordingly.

You mention that you try to avoid back-reaming due to shale break-out in the upper regions of your well bore. Does this breakout happen all the time, or just when the BHA is across a specific zone? There are Lo-Energy practises that have been utilised successfully in various places to combat this - back ream to below the fragile zone, clean the well bore up, trip through the fragile zone, continue back-reaming is one option. But patience is the name of the game when back-reaming. Can be a stand an hour, maximum I have done is about 8, understanding the faster you go the greater the chance of pack-offs and possibility of damaging the wellbore.


Regards, Iain


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