Multi-Zone Gravel Pack Techniques: Case Studies From the South China Sea Xijiang Development

Abstract Xijiang is the first Pearl River Mouth Basin Development in the South China Sea employing gravel packs. These fields, comprised of multiple-layered reservoirs, are characterized by unconsolidated, friable, and high-permeability sandstones that must be commingled for economical production. This paper will discuss the specific reservoir characteristics and parameters that affected completion scenarios in the development of these fields and how the needs for sand control, zonal isolation, high-rate production, and reduced completion duration have been addressed. Particularly significant in development of the projects has been the design of two completions systems specific to the Xijiang reservoir conditions that accomplish gravel packing and mechanical isolation of individual sands while minimizing the number of trips made into the wellbore. The single-trip dual-zone (STDZ) system is used when two zones must be gravel packed, and the multi-zone system has been employed when there are as many as 8 zones in one wellbore that must be gravel packed.