ABSTRACT
Some cases of cementing of casing in hydrocarbon wells are considered in Kutasov and Eppelbaum (2012a, 2013a, 2013b, 2014).
Below we will consider a method of downhole temperature prediction while cementing of casing. It will be shown that for deep and hot wells the heat generation during cement hydration may cause a substantial temperature increase in the annulus. This factor must be taken into account in cement slurry design. Temperature and pressure are two basic infl uences on the downhole performance of cement slurries. Temperature has the more pronounced infl uence. The downhole temperature controls the pace of chemical reactions during cement hydration resulting in cement setting and strength development. The shut-in temperature affects how long the slurry will pump and how well it develops the strength to support the pipe. As the formation temperature increases, the cement slurry hydrates and sets faster and develops strength more rapidly. Cement slurries must be designed with suffi cient pumping time to provide safe placement in the well. At the same time the cement slurry cannot be overly retarded as this will prevent the development of satisfactory compressive strength. The thickening time of cement is the time that the slurry remains pumpable under set conditions. While retarders can extend thickening times, the thickening time for a given concentration of retarder is still very sensitive to changes in temperature. Slurries designed for erroneously high circulating temperature s can have unacceptably long setting times at lower temperatures.
