Open-Hole Gravel Packing with Solid-Free Oil-Based Carrier Fluids – A Case History and World Class Triumph for the Industry

Abstract:

In many open-hole completions in unconsolidated reservoirs, the preferred method of sand control is a conventional gravel pack across sand exclusion completion screens. To date the gravel pack options available for horizontal or highly deviated wellbores have been the use of brine-based gravel pack carrier fluids or the use of viscous gel packs using alternative path screen technology. The first option, using brine as the carrier fluid, has limited applicability because many reservoir intervals have brine-sensitive shale that, if not stabilized, can disrupt the gravel deposition during the alpha-beta (a-b) packing process, especially in long intervals. The second option, using alternative-path screens and viscous carrier fluids, overcome the shale destabilization issues but not without a compromise in the quality of the pack or the higher price tag.
A third option is now available that utilizes a new, solids-free, invert emulsion gravel pack carrier fluid. This option overcomes the issue of shale destabilization and interupted gravel deposition often associated with brine packs because it avoids the exposure of water-sensitive shale to aqueous fluids.

This paper provides the design details of a carrier fluid that overcomes the technical hurdles of a conventional brine-pack operation as well as the fiscal limitations associated with alternative path technology. Included are the planning and execution details of a 5-well, back-to-back gravel-packing operation from an offshore platform in the Bualuang Field, Gulf of Thailand whereby successful gravel deposition occurred on each well using a invert emulsion system as a carrier fluid. The results presented of this case history sequence clearly demonstrate a world class break-through and triumph for the oil industry.