Sustainable cement slurry using rice husk ash for high temperature oil well

Abstract

In oil well cementing where high temperature are involved, a silica source is add to the cement composition to inhibit cement sheath compressive strength retrogression. The mechanical properties of cement used in oil wells may benefit from the incorporation of rice husk ash (RHA) due to its high silica content. RHA has also become attractive as cement additive owing to its low cost and renewability. The aim of the present study was to develop a cement slurry for high-temperature oil well using RHA as anti strength retrogression additive. A typical G cement slurry was prepared with 40% of RHA and submitted to curing cycles of 7–28 days to evaluate the influence of the RHA at both the bottom hole static temperature (BHST) and 300 °C. The results showed that the addition of RHA increased by 30.55% the compressive strength after curing for 28 days at BHST conditions and by 11.18% at 300 °C. XRD analysis of high temperature cycles showed the presence of xenotlite and tobermorite, which are crystalline phases responsible to maintain the cement compressive strength. The RHA has been shown to be a sustainable alternative to commercial silica flour. In addition, the present study envisages the RHA disposal to be considerably reduced by its application in the petroleum industry.