INVESTIGATION OF FLY ASH EFFECT ON RHEOLOGICAL AND FILTRATION PROPERTIES OF DRILLING MUDS

The aim of the present study is to improve rheological and filtration properties of water based drilling fluids by addition of fly ash and to investigate the physical and chemical properties of the additive and drilling mud mixed with 1, 2, 3, 4, 5, 6 and 7 % w/v of fly ash. The chemical composition and the morphological structure of the fly ash and the drilling mud mixed were analyzed by XRD, XRF and SEM. The physical properties of the drilling mud were determined based on API standard, including all filtration and rheological properties. The result of analysis showed that the rheological properties of drilling mud mixing 6% w/v fly ash increased 13 % cP of apparent viscosity, 39 % cP of plastic viscosity while decreased 43 % of the gel strength (10-second 45 % and 10-minute 40 %). At the same time, it was also found that fly ash of 6 % w/v added into the drilling mud reduced the filtration loss about 22 %. Comparing the all data suggested that the water based drilling fluid mixed with ratio 6 % w/v of the fly ash is a promising additive not only the economical way but also the environmental perspective, since the fly ash is a waste combustion byproduct.