DEVELOPMENT OF LIGHTWEIGHT SLURRIES USING HOLLOW CERAMIC MICROSPHERES FOR APPLICATION IN CEMENTATION OF OIL WELLS
Cementation; Lightweight slurry; Fly ash; Microspheres;
Geopressures are related to the main problems caused during the drilling of wells, and any damage caused to the formations may compromise the safety and economy of the well. Therefore, alternative solutions are needed to control the pressures exerted during the displacement of cement slurry, such as changing its density, commonly called the slurry's weight. One way to reduce the density of the slurries is to use microspheres in their composition. Among these, the hollow ceramic microsphere, as a by-product of the burning of mineral coal, has a lower cost and is environmentally sustainable. Given the above, the objective of this work was to develop cement slurries with low specific weight, using hollow ceramic microspheres (fly ash), for application in primary cementing operations of oil wells. The slurries were formulated at densities from 11.5 lb/gal to 12.5 lb/gal. The best formulations were then used to develop slurry systems for application in wellbores with low fracture gradient zones. The technological characterization tests were carried out following the procedures established by API RP 10B/SPEC 10A and PROCELAB, 2005, among which the compressive strength and stability tests stand out. The results showed that it is possible to partially replace Portland cement with industrial waste, making its application sustainable, low cost, and with satisfactory mechanical properties for application in oil wells, with compressive strength between 3.0 and 13.5 Mpa.