Improved palm oil fly ash as a better oilwell cement additive

Abstract

Oil well cementing is the process of mixing and placing cement slurry in an annular space between a casing string and drilled hole. Today, oil wells cover a wide range of depth and temperature conditions than any time history. Therefore, the cement slurry compositions should be designed to encounter pressure to more than 30000 psi and temperature up to 700oF. It has been possible to accomodate such a wide range of conditions only through the applications of additives to modify the available oil well cement for the individual well requirements; i.e., allowing succcessful slurry placement, rapid compressive strength development, and adequate zonal isolation. All additives are imported and, quality and economic problems have been observed, therefore it is the best time to highlight the potential of local natural and waste material to be used as additive to the oil well cement. This paper presents the results of burning conditions effects to palm oil fly ash (POFA) performance as a class G cement additive. Laboratory experiments had been carried out by using the class G cement slurry with various amount of palm oil fly ash that was produced at different burning temperature and time, and BJ-Blue was used for the comparison purpose. The AAS was used for the chemical analysis and API Specification 10 for cement slurry performance test. With increase burning temperature and tume and amount added, the results show less fluid loss and free water, better compressive strenght and thickening time. From these results, it can be concluded that better POFA can be produced from higher burning temperature and longer burning time. The class G cement with improved POFA performed well than with standard BJ-Blue. The total cement material cost can be reduced since POFA is a local agricultural waste product.