Reducing Carbon Footprint: A Field Study of Low Carbon, Cement-Free Well Construction

Well construction includes hard-to-abate emissions, notably from its well cementing operations. Reducing carbon emissions associated with cement is a priority because cement is used in nearly every well drilled today, with an impact of approximately one ton of carbon emissions per ton of cement used. This paper presents an innovative technology: making well cementing without Portland cement at scale a reality. Geopolymers made from aluminosilicates comprising industrial waste materials are considered a sustainable alternative to Portland cement. Existing geopolymer formulations found in academia are not scalable for land-based well construction cementing operations, as they are unmixable using standard equipment and have increased health, safety, and environmental risks (HSE). Thus, a novel geopolymer blend was engineered for well construction applications that is mixable with existing equipment and reduces HSE risk through eliminating the onsite handling of corrosive liquids. Additionally, a Sustainability Assessment Tool was created to quantify and compare carbon emissions at different steps such as manufacturing materials, transportation, and onsite operations. Field trials of the novel geopolymer blend in the fast-paced Permian Basin confirmed this technology could be implemented within the oilfield cementing process with the same efficiency and efficacy as the conventional cement-based operation. During the field trials, the geopolymer system was deployed without any changes to the field mixing equipment and without any HSE incidents. Sonic logs of a subset of wells confirmed conventional logging equipment can detect set geopolymer within the wellbore and validates industry-standard simulators to predict placement. Using the Sustainability Assessment Tool confirmed that the emissions from the slurry components are more significant than the emissions related to logistics and operations. The quality and availability of the emission factors of slurry components are key, with multiple data sources considered for reliable quantification. The proposed low-carbon geopolymer cement-free system in current field application eliminates up to 85% of Scope 3 CO2 emissions compared with conventional Portland cement systems. The industry can capitalize on these benefits with no change in operations or increased HSE risks. Decarbonizing the well construction process while maintaining safety and performance standards is critical to the oil and gas industry's pathway to meeting emissions reduction targets. This geopolymer cement-free system is a breakthrough that delivers industry-standard zonal isolation capabilities while significantly minimizing environmental impact from upstream oil and gas production.