This text is republished from a recent LinkedIn discussion. Follow the conversation on Linkedin.
If it was difficult to drill, and challenging to set the casing, Would you expect the cementing to be the easiest part?
Dear Group members, I have to apologise because It is already more than a month since our last challenge (cement challenge No. 3). During this period, I was dedicated to launching my free technical support site: https://better-cementing-for-all.org and I would like to thank you all for your support and level of response.
In this opportunity, I would like to post a challenge related to pre-job planning. Despite the way this question looks, this challenge applies to drillers, cementers and the whole drilling team.
Referring to a well’s section:
If it was difficult to drill and difficult to set the casing, Would you expect the cementing to be the easiest part?
Hints or common lines of thinking:
– Translate drilling events to cementing challenges or opportunities.
– Be ready to adjust your cement program, why? Or why not?
– Some cementers would say: We only pump Cement! 🙁
– Some drillers would say: We don’t want change in the ‘standard’ cement program 🙁
– A best practice is not necessarily a generic method, or is it?
– Cementing is not an isolated event, or is it?
– It is just cement. What else you need to do? Give me a break!!
Looking at the quality of the responses to the first three challenges, I am excited to see what you guys are going to say about this one. The best comments will be posted on my site (https://better-cementing-for-all.org), as I believe they will be quite educational.
Cheers
L. Diaz
P. D. You might have noticed that I am still skipping a challenge about zonal isolation interpretation… I think that is a topic just too controversial… It is like soccer…:) I promise that I will do it next time.
Pujiyamto Krismowo There are three questions for that:
1. If the Drill and casing success to TD as Desired then the pressure is good when circulation there is no reason cement job is canceled.
2. If the drill and casing placed as desired is failed why do we have to make a cementing job?
3. If the drill and casing reach TD but when circulation there is still high press there is no reason to take cement job.
Mohamed Guedda It all comes to the circulation;
If you have good returns after you TD then you shouldn’t find any problems cementing.
If you lose returns, then you have to re-establish it before you can cement and that can be done by pumping lost circulation materials or by doing a squeeze job.
But you have to take to account that if you don’t need your cement all the way up past the lost circulation zone and if it’s OK with the railroad commission you can pump your cement and then you go, and do a temperature log to see where is your cement at.
There are many different Scenarios and different solutions to this problem.
Matteo Loizzo Glad to have you back Lenin, and thanks from all of us for your web project!
Back to your question: if we focus on a narrow mud window then this could be both a boon and a bane. If you have high pore pressure, then your cement job will be hard: remember that chimneys caused by migrating fluids are still only partly understood, and many a witch doctor will be selling you proven remedies.
If, on the other hand, the driller grumbles about stuck pipe and you’re so desperate to call in a geomechanics expert to make the hole stable, then your cement job will be the envy of your neighbors. If that is, you can push your casing to bottom and establish circulation. Creeping formations are the best barrier ever, whether alone or in combination with cement.
Lenin Diaz Matteo Loizzo, if you are referring to hole stability issues before and during cementing… I must confess I have a pseudo-masochist obsession with those… Following years of being exposed to this, I have to say I enjoy this situation now… Just because when it happens we are not blind, we can see and remain in close contact with the well thru pressure (our eyes and ears), and I like that talk.
Being prepared for a potential hole stability problem and/or just sweeping its product in cementing, i.e., the risk of pack off, is a typical moment when the drilling team must work together to develop and execute a plan.
Arthur Evertsen By revisiting the drilling and casing running history you could get a good picture where the trouble zone(s) are with regards to tight spots or losses. Identify which, if any, trouble zones in the planned cemented area. Casing point is generally in more competent formation.
What is the status before cementing – do we have returns or not?
Revisit cement job objectives – unless needed to isolate permeable zones with flow potential – job objective might be limited to tag the shoe.
Evaluate if we need to use primary or contingency slurry (shoe squeeze slurry) and volume to pump.
Depending on TOC evaluate the risk of a trapped annulus.
If a change to cementing procedure, evaluate lab testing sufficient to carry on without any further lab testing.
The criticality of not having returns and job objective is to isolate permeable zones with flow potential is a valid reason to pull casing for sidetrack or wiper trip unless specific trouble zones are way above the planned cemented area.
Clayton Adonis Browne Cementing is the critical part because it will accomplish objectives to ensure the well live as long as possible without a casing collapse. The well maybe in an unknown area like wild-cat and down-hole geometry can vary. Therefore several contingency plans must be set up beforehand because things can change very rapidly within the hour. With the hole drilled and adequately conditioned, tripping to run casing can be a decisive factor. So an additional wiper trip should be considered simulating the time the casing will take to be on the bottom. A good practice is to slip and cut the drilling line before that trip so to give the hole static time, so when the wiper trip comes, it can determine the condition of the hole. It also may not only be able to run a single string and be cemented correctly in separate stages so a multi-stage cementing process should be considered. What we do not want to do is simply pump cement.
José Manuel Bonifacio If I supposed there are problems during drilling and introduction casing. First, before introduction, I will check with the BHA circulation and then if I check existing lost circulation I will select casing equipment that not create effort during introduction casing. Then when we stay at the bottom the circulation, the well informs us (pressure, volume flow and density of cutting) and then will select the type of slurry cementing (density and composition chemistry) and that’s all.
Rich Cooper Difficult drill and casing run can present many different issues with the cementing. Including cave off/wash out which present TOC/slurry vol problems, tight drill (no reamers)/tight turn can have higher pressures due to poor centralization/decreased annular space and also may have micro-annulus issues, and then there is lost circulation which gives trouble to all phases of drill/casing/cementing
JUAN SOTO Friends: I will ever consider the cementing program as a cocktail of choices, in the beginning, the first approach reflects the surrounding cases, like neighboring wells, similar oilfields or well geometries, drilling case histories compared to actual previous phases. Then, as the drilling activities are evolving, the cement program would be pinpointed, choosing a prime schedule, always keeping the option for at least one pre-visible condition. I don’t like stiffness in such a complicated (on activities and implicated staffing) procedure. Nevertheless, if you have enough time to ‘smell’ the data before and near after reach pay zone, you can figure out what your prime procedure and fluids choices are and re-plan accordingly.
JUAN SOTO The final cementing program has to be justified by the actual job environment and procedure shared and authorized, so, keep enough safety time on your slurry(ies). Usually, there is no time to change the formulation without economic reasoning. Anyway, circulation properties will give you a final hint on what could happen.
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