Investigations on the surface well cement integrity induced by thermal cycles considering an improved overall transfer coefficient

This paper presents a unique experimental investigation of thermal cycle behavior of cement with focus on surface casing cementing. A more accurate assessment of overall heat transfer coefficients, directing efforts towards increasing the efficiency and understanding of thermal well design has been also performed in order to better understand the induced thermal loads on cements under complex scenarios. Thermal mixing laws have been used to determine the approximate impact of drilling fluid invasion and filter cake formation within rocks' pores on overall heat transfer coefficients. In an experimental approach it was noticed that applying temperature cycles to fresh cements (curing time less than 21 days) will lead to mechanical strengthening of the casing-cement-system, enhancing well integrity, whereas old cemented wells will lose strength.