ABSTRACT:

The paper discusses a novel approach to remove the dry-blending of cement by adding all the additives (extenders, weighting agents, silica etc) into the mix-water directly prior to the job. The benefits to be attained with regards to health, safety, the environment, slurry quality and logistics, by using neat (unblended) Portland cement throughout the entire well construction, is discussed. Drilling a well often requires consideration of a number of formation types, weak unconsolidated formations in one zone can be followed by over-pressured formations in the next. For the annular cement to provide proper isolation across those zones it might be required to dry-blend and ship, for each well, a number of cement blends, e.g. lightweight blends, neat cement, silica cement for high-temperature and even dry-blends containing weighting agents. Case histories and job procedures using each of the additives are presented showing how each has been successfully mixed into the slurry mix water. Also, laboratory results are shown which demonstrate the advantages gained by using each of these products, along with some comparisons of other possible solutions

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