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Perforating during Night
19 February 2018

Good day dear Colleagues,

are your company policies, standards or procedures allow you to perforate during night times?

Would it be allowed, if you do not bring the fluids to surface?

Does the perforation technology (electric line, slick line with shooting nipple or TCP) play a role in that decision?

I would be interested how your companies treat this subject.

Thank you very much for some short answers on this subject in advance!

Best regards,


6 answer(s)
CDC Scotland
Total Posts: 3
Join Date: 08/04/14
Hi Heiko,

Some operations I worked in did allow and some did not.

I always felt it was a subjective decision.

Pumping acid at night was always a no, no. 

But again I felt these were rules laid down when inadequate lighting technology was available. 

And presumably something had gone badly wrong previously. 

Good Luck.
Integrated Well Intervention Advisor
Total Posts: 7
Join Date: 26/03/18
We always perforated at night, just like we always fraced at night. There is no issue with proper risk assessments in place
Managing Director (
Relentless Pursuit Of Perfection Ltd.
Total Posts: 413
Join Date: 10/01/05
Hi Heiko

I agree with Wally and Peter.

With my 'continuous questioning attitude', I have raised this question myself many times as Drilling Supv and then Drilling Supt.

In addition to the comments and suggestions already raised, I recall that offshore it was easer to see any leaks in the system on any 'sheens on the water' during the hours of daylight.  Therefore, good testing of the lines and powerful lighting systems are a must.

We also discussed H2S and the fact that it would be easier for personnel to escape from an H2S-event in daylight than at night. Therefore, if you cannot be 100% dure that there will be no H2S, then personnel egress must be considered.

However, I was NEVER convinced enough that there was a solid case for waiting for daylight to bring hydrocarbons to surface. 

In a small way this was affected by my first ever trip offshore (1982) as a rookie Reservoir engineer for a DST of the Emerald field in the North Sea. Even with a nitrogen cushion helping to achieve underbalance, it took over 24 hours for hydrocarbons to reach surface! The sun has already set!

So, my question about hydrocarbons-to-surface is: how can you tell (before perforating!) how long they will take to reach surface anyway?

For me; Assess and document the risk, put mitigations in place and I am fairly certain that it makes sense to "go for it".


Total Posts: 113
Join Date: 05/03/08
Hello Heiko,

My experience and indeed question is the same as Wally and Peter.

In my experience, perforating at night has never been an issue, but first fluids to surface has always been delayed until daylight. This is irrespective of the perforating regime or rig type.

During subsequent tests with the same equipment - i.e. perforating a different zone - then we have been allowed to perforate and flow at night.

In the old days, the reason was always 'so we can see what is happening'.

In that respect, I agree with Peter. We now have better equipment, more reliable connections, more instrumentation, flare ignition systems that actually work etc, so is this still a valid concern?

I would venture that in many cases it is not, although individual circumstances would have to be taken into account and fully risk assessed.

For example, I'd be far more inclined to let first fluids to surface at night on a modern offshore rig with an experienced crew and relatively new equipment, than on a Land Rig with a bunch of newbies and beaten up old equipment that took several goes to pass the pressure tests.

Best Regards

Drilling Specialist/Well Engineer/Training Consultant
Kingdom Drilling
Total Posts: 361
Join Date: 10/01/05

As per Wally's comments, many times during the wee hours we have continued to operate. No waiting required (on a case by case fully risked assessment basis) 

My question to this forum would be that this is a sort of another 'oil fields myth' is it not? One cannot recollect this ever being a regulation requirement? 

This assumption may be wrong if so someone could perhaps provide evidence form somewhere that states otherwise.

My understanding is that Perforating at night goes back to wooden rigs in shallow water, where with oil laterns burning as the only source of light that could be provided. Flame source presented a risk, hydrocarbons could not be detected, there was risk of oil/gas in rig work areas, etc, Hence teams had to wait till daylight until one could see. 

With modern rigs and electricity and light provided and all other HSE and operational safety systems, factoring in place. Why the need to wait? Where's, what are the risks?

Whether one is on land, shallow offshore or in deepwater.
If standard, Risk assessment, guidelines, best practise, management of change followed etc.

No reason why any task cannot be conducted safely effectively and efficiently if all factors duly risked, managed controlled and catered for 24/7 (weather, operating and environmental conditions permitting.) 

Note: Where at times there may be a valid reason why ops may have to wait. 
Well Services Supervisor
Total Posts: 3
Join Date: 17/03/11
Hi again Heiko,
Again, from the experience of many years, I've perforated during the hours of darkness, flowed for 10 minutes to rid us of the over-pressure, getting an initial build-up before opening up at a time to have hydrocarbons to surface for first light.
No, we haven't altered that procedure for differing perforating regimes.

Wally Burnett
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