The optimal cement slurry mix design principle
There is one principle that I have learnt to always keep in mind when talking about designing a cement mix slurry. This principle is easy to remember: ‘the simpler, the better.’
In this context, this means using the lowest amount of additives as is reasonable, and using them in their lowest effective concentration that can still provide the desired cement slurry features.
We base the principle on the assumption that there is a level of interaction* between all the components in a cement slurry. So, by reducing the number of elements and their concentration, the side effects would be minimized.
However, sometimes this is not that easy. The cement slurry mix design formulation would strongly depend on the experience of the laboratory itself (database) and the lab technician.
The flowchart below is a simple point of departure to design conventional cement slurry systems for each well-cementing laboratory.
Depending on workload, experience, availability of quality cement and chemicals, this cement slurry design flowchart is adapted to ensure that we can deploy reliable fluid systems.
(*) Interaction = the balance between desired (targeted) and negative (side effects) reactions.
What steps do you take to make corrections in the following cases?
Please share in the comments section below your solutions for when:
- Rheology is too low
- You have gelation problems
- There are compatibility issues with the mud
- The static gel strength is too low (45 min)
- The compressive strength development is too slow or the max. value is too low
BONUS: Visible Vortex @ 12000 rpm (blender) = Good surface mixability