Benoit Vidick

2 Chemistry and Characterization of Portland Cement

Publisher Summary This chapter deals with the physical and chemical properties, and the performance of the remarkable material, which are crucial to every facet of well cementing technology. The chapter reviews the manufacture, chemical composition, hydration chemistry, and classification of Portland cements. Well cementing exposes Portland cement to conditions far different from those anticipated by its inventor. Cement systems must be designed to be pumped under conditions ranging from below freezing in permafrost zones to greater than 1,000° F (538°C) in some thermal recovery wells. After placement, the cement systems preserve their integrity and provide zonal isolation during the life of the well. It is possible to accommodate such a wide range of conditions through the development of additives which modify the available Portland cements for individual well requirements.

5 Mud Removal

Publisher Summary This chapter reviews the work performed to date, contrasting the opposing viewpoints, and distilling some mud removal guidelines, with which the majority of workers in this field agree. The mud removal process demonstrates the complexity of the problem that the industry is facing. The relationships between the properties of laboratory-prepared and field-prepared cement systems are adequately characterized. The modeling and experimental work performed have allowed the industry to define simple qualitative guidelines for improving primary cement jobs. Mud gel strength, yield point, and plastic viscosity should be reduced to a minimum value before removing the drill pipe. The centralization should be obtained through a proper centralization program. Prior to pumping the pre-flushes, sufficient time should be allowed to circulate at least two annular volumes of mud at the highest rate possible, without losing returns; a chemical wash should also be used.