Abstract
Hollow-glass microspheres (beads) are widely used to generate light weight cement slurries for cementing across highly depleted zones and weaker formations; this paper discusses tailoring of a cement slurry and the execution of cementing operations for the successful deployment of an innovative liquid bead solution instead of the conventionally blended beads to achieve zonal isolation for a development well in Malaysia.
Usage of dry bulk blended beads poses many challenges, such as rig and vessel silo management, quality control of beads, multiple blends on the rig and excess back-up blends. A new approach has been proposed using a liquid bead system to produce a light weight cement slurry by adding beads stabilized within a suspension fluid as another liquid additive to help eliminate the need of dry bulk blending of beads and at the same time accomplishing all the obligatory cement properties for a production casing section in depleted zones.
A successful offshore application of liquid beads was executed in a production casing, meeting all the necessary property requirements for cementing in a depleted zone. The cement slurry was developed in a local field laboratory with standard laboratory testing techniques and equipment. Liquid beads can be added to the cement slurry using liquid additive pumps or batch mixed on the surface. Considering the slurry volume of the production section and the importance of a homogeneous cement slurry, liquid beads were injected into the recirculating line of the cement batch mixer. A yard trial was performed prior to the actual job which validated the easy transfer of liquid beads. Relative to the conventional dry-blended approach, this economically more efficient liquid bead cement system was easy to mix and achieved the required design density without any operational issues. The cementing operation was executed with full returns throughout the job at maximum planned displacement rates. To evaluate cement placement, a post job analysis was performed.
The first application of this liquid bead technology in Malaysia was to generate a light-weight cement slurry and was successfully implemented for a 9-5/8" production casing where 167 bbl of the liquid bead base cement slurry was mixed, pumped & effectively placed.
