Abstract
Geopolymer, an aluminosilicate-based alkali-activated cementitious material, can be used as an alternative to Portland cement in oil and gas wells. While the current literature on geopolymers primarily focuses on the construction industry, this work was aimed at studying the potential use of novel geopolymers for well construction applications such as primary cementing and lost circulation control. It was recently discovered that hydroxide-activated geopolymers have the ability to solidify non-aqueous drilling fluids (NAFs, i.e. with synthetic or oil based muds) up to 60/40 geopolymer/mud ratio (by volume). The primary benefits of such a blend include better compatibility of the slurry with NAFs, reduced risk of poor cementation, inexpensive source material as well as an environmentally friendly on-site/in-situ disposal of NAFs. The rheological properties, short-term and long-term compressive strengths of the geopolymer/NAF blend can be tailored to any specific application. In this work, the effects of pressure, oil/water ratio variation and internal brine phase composition in the NAFs were systematically studied. Both liquid-form and solid-form sodium silicate activators were used to form silicate-activated geopolymers. The slurry design was targeted for specific applications. For lost circulation control, the geopolymer slurries were deliberately blended with non-aqueous drilling fluids to achieve rapid gelation and setting characteristics.
