Desenvolvimento de pastas leves utilizando microesferas ocas de cerâmica para aplicação em cimentação de poços petrolíferos

Abstract

Geopressures are related to the main problems caused during the drilling of wells, and any damage caused to the formations can compromise their safety and economy. Therefore, alternative solutions are needed to control the pressures exerted during the displacement of cement slurries, such as changing their density. One way to reduce the specific mass of the slurries is to use light aggregates in their composition, and among these, the hollow ceramic microsphere has potential for this application. In addition, hollow ceramic microspheres, as they are by-products of coal burning, have a low cost and are environmentally sustainable. Given the above, the objective of this work was to develop slurry designs with low specific weight, using hollow ceramic (fly ash) and silicate microspheres for application in primary cementing operations of oil wells. The hollow ceramic microspheres were characterized by pycnometer, granulometric analysis, XRD, and XRF to determine their class according to ASTMC618−12A. The slurry designs were formulated with specific masses between 11.5 lb/gal and 12.5 lb/gal. The tests were carried out using the practical recommendations of API RP 10B-2 and PROCELAB. According to the stability tests, sodium silicate had the most significant influence on the cohesion of the particles, with a concentration of 0.3 gpc being the most suitable for systems that contain light aggregates in their composition. The studied systems showed compressive strength results between 3.0 and 13.5 Mpa in 24 hours of curing, satisfactory results for slurries with low specific mass, proving the potential of partial replacement of Portland cement by industrial waste, making its application more sustainable and less expensive.