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 […]
Cementing. Challenges across permeable zones
This article will provide you with some actionable suggestions for cementing across permeable zones. In previous posts, I have already talked about the effect of formation permeability on the apparent cement presence behind casing, as seen on cement logs. (See: Excellent cement job, but with terrible results … how is this possible?) Keep in mind that […]
Cement Slurry design Basics
First, here is a handy table to simplify the process of cement slurry design: Additive Type Purpose Considerations Extenders IWater, Bentonite (clays), pozzolans, amorphous silica, Sodium Silicate, etc. Reduction of hydrostatic or greater economy.Lower slurry density from less than 15.8 down to 11.5 ppg, typically.Higher slurry yield (more slurry volume per sack). Change slurry rheology […]
Excellent cement job, but with terrible results … how is this possible?
We all want to achieve an excellent cement job every time, we pride ourselves in achieving this. can face a common challenge while attempting zonal isolation during primary cementing: the resulting lack of “good bond” – as measured with cement logs – across permeable zones. This is typically seen as a sudden decrease in cement […]
What can you expect in an Expert Post-Job Analysis?
Please support better well cementing. A post-job analysis is among the first steps to developing a learning organization, but what is a learning organization? Before answering this question, just very quickly, let us answer a more basic one; where does quality start? Moreover, by “quality,” I mean measurably meeting requirements, expectations or achieving objectives. Quality […]
How many cementing centralizers does one really need for a given well?
The primary objectives for centralization design (that is the number, type and spacing of cementing centralizers) should satisfy both the need to get the casing to the bottom as well as zonal isolation. However, despite this being apparently simple and obvious, cementers do not seem to appreciate the fact that without the casing at target […]
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