Hollow glass spheres (HGS) provide an attractive method to reduce densities of drilling fluids and cement slurries for different objectives. There are several pressure ratings of HGS and selecting and testing the right type for the suitable application is important.
The objective of this paper is to evaluate performance and stability of HGS by formulating HGS based fluids in different pH conditions, formulating low density water based drilling fluids with HGS as density reducing additive, and formulating low density cement with HGS as density reducing additive
The evaluation of the stability of low-density inhibited water-based fluids formulated with HGS in diverse pH environments was for their potential application in Wasia formations in Saudi Arabia. Intensive testing of the fluids included rheological properties, pH and density measurement before hot rolling (BHR) and after hot rolling (AHR) in different pH environments at high pressure and high temperature for long time (up to 4 days).
The evaluation of the stability of low density cement utilizing HGS was for their potential to cement shallow casings in gas wells and oil wells in Saudi Arabia. In this study, we present extensive lab work that included rheology measurements, thickening time tests, free water and sedimentation tests, fluid loss test and compressive strength test.
Data generated supported the use of low density fluids formulated with HSG in Wasia Formation when applicable. Also, this study supported the use of the cement examined in shallow conditions in gas wells and oil wells. The shallow conditions simulated in the lab tests were 158ºF static temperature and 2500 psi.