Which gravel pack type is limited to single zone completions?

• A. Underreamed-casing gravel pack
• B. Open-hole gravel pack
• C. Conventional gravel pack
• D. Perforated annulus gravel pack

Answer: (A)

The concept here is how zonal isolation is achieved in a gravel-pack installation. An underreamed-casing gravel pack creates one enlarged cavity around the production interval by underreaming the casing. The gravel is placed into that single cavity, so you effectively have one continuous gravel-packed zone. There’s no built-in way to subdivide that cavity into independent sections for multiple zones, which is why this approach is suited for a single-zone completion.

Other gravel-pack configurations are designed to support multiple zones because they can include separate, isolated sections (with packers or separate perforated intervals) that allow sand control in several zones without mixing them into one cavity.