A Comparative Study of Mechanical Properties of Density-Reduced Cement Compositions

Abstract

Summary This paper discusses the tests conducted to determine the mechanical properties and the integrity of the cement sheath when subjected to cyclic loads. In addition, the effects of well operation on cement sheaths of different mechanical properties are analyzed, and the results are discussed. The results clearly demonstrate the importance of both laboratory measurements of cement-sheath mechanical properties and engineering analysis of the effect of well operations on the integrity of the cement sheath. Lower-density cement systems are discussed in this paper, along with how the density was lowered by incorporating conventional additives such as Pozzolanic beads (cenospheres) Hollow glass beads Gas bubbles Water-binding additives Silica fume Fly ash Primary cementing compositions for oilwell applications are becoming increasingly complex and challenging because of the extreme well operating conditions encountered. The stresses exerted on the cement sheath during well operations could be severe enough to damage the cement sheath and negatively affect the safety and the economics of the well. The results discussed in this paper should help operators design a cement sheath that can withstand the stresses from well operations, thus improving the safety and economics of the wells.