If we consider the main variables to ensure proper mud in hole replacement with cement: stand-off, fluids rheology (friction pressure hierarchy) and placement regime (as related to pumping rate); the amount of cement left in the hole (cement coverage), if no losses, quickly reduces (leading to increase cement returns, either to surface or above the […]
Where is your TOC now? Cementing Calculations Sheet in Excel
Before we get into the cementing calculations sheet available below, first some background. For some time already, I have been receiving requests from friends and readers, mostly drilling engineers and well-site people, to provide a quick and fact-based tool to estimate the top of cement (and all cementing fluids) after a job. A tool that […]
All you need to know about Bentonite in Cement Slurries
Let’s have a quick overview regarding bentonite. It is easy to find references online regarding bentonite as a cement extender, the way it works (or I should say reacts), and why additional water is required when using it as an extender. Here I will try to explain as simply as possible, for readers of all […]
Forward thinking reverse cementing
I recently participated in a discussion about opting for the best alternative between conventional and reverse primary cementing to deal with losses and frequent difficulties to reach the required TOC in an intermediate well section. The interesting thing in this discussion was that the majority of the participants had no experience in doing reverse cementing. […]
Mud Displacement, the ‘mystery’ factor in gas and fluids migration
Very often I find myself helping people having issues with fluids migrating following primary cementing. In all these cases, it is always fascinating to see the frequency of this problem nowadays. Especially with the involvement of expert services companies and the availability of state-of-the-art engineering and products solutions. I have already written here about fluid […]
Primary Cementing Checklist (Customer)
Before we delve into the primary cementing checklist, imagine that you are the person in charge of well construction operations. It is nighttime, and the company man is resting (contrary to ‘normal’ people, a co-man needs noise to properly rest, because noise means that ‘all is working’). As a junior or night well site leader […]
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