Influx zone characteristics These wells may show high dogleg severity in the intermediate section. Depending on the type of formation drilled across, there could be a tendency to form sort of keyseats, not only low side but also high side. They tend to get worse with additional drill string work, such as trips, reaming or circulation. […]
LCM Equipment: Using it Through Float Before Cementing
Using LCM through float equipment before cementing In some cases, we can see losses while running the casing or circulating before cementing. These losses open up the alternative to pump a Loss Circulation Material (LCM) pill as a possible mitigation method. This will then lower the losses ahead of the cement job itself. However, based on my experiences […]
Good or bad cement job? 7 Criteria
Well, this is the question: Was it a good or bad cement job? The final answer will depend on the objectives of the job. We ask ourselves, were they met? In most cases, additional information is required, like a cement evaluation log, a pressure test or even further data during the well’s completion. However, some immediate […]
Cement Slurry Contamination: Prevention
This post provides additional information for those who need more detail regarding cement slurry contamination. This is a follow-up post to previous posts where we covered fluids intermixing (as in liner cementing and rheology in primary cementing). What are the consequences of contamination? Poor Cement Log Evaluation: Cement log evaluations can show poor cement in Liner […]
What is Rheology? Key to Cement Coverage
What is Rheology? One of the most important things we, as oilwell cementers, must understand is rheology. In our line of business, Rheology is the key to cement coverage and zonal isolation; which is the sole goal of well cementing. However, as simple as this can be, it is incredible how easy it is underestimated and […]
Cement Retarders: Synthetic Vs. Organic
In my experience, bio-based oil well cement retarders do not provide the consistency needed to control thickening time accurately. (This is at least, the case among types of cement used in oil wells). The main reason is that the production of natural organic retarders varies from lot to lot and batch to batch. The problem with organic […]
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