Tommy Grigsby

Gravel Packing a 2,400-ft Openhole Horizontal Interval

A typical economic requirement of most high-cost deepwater development projects is high-initial-rate (> 15,000-B/D oil wells or > 70-MMcf/D gas wells) completions. To achieve these rates from pay sands in this field, 2,000--2,500-ft horizontal completions are used. Conventional openhole horizontal completions have been used in the Gulf of Mexico (GOM) since the early 1990`s. However, the number of failures experienced by some operators has raised questions about the reliability of this type of completion. In deepwater projects, high-rate production and completion reliability present major challenges to operators, and traditional methods of sand control often have not been able to satisfy the changing conditions. The full-length paper presents a solution that combines gravel packing, enhanced downhole-tool capability, and advanced fluid technology to solve sand-control problems. The successful application of the first extended, horizontal openhole gravel packs in the northern GOM proved that gravel packing can be applied successfully to extended horizontal boreholes.

Multi-zone gravel pack techniques : Case studies from the South China Sea Xijiang Development

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 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.