Which of the following statements describes a negative skin?

Which of the following statements describes a negative skin?

• A. Negative skin increases the restriction to flow toward the well.
• B. Negative skin reduces the reservoir pressure.
• C. Negative skin reduces the restriction and effectively increases the bore radius.
• D. Negative skin has no effect on flow.

Answer: (C)

Skin describes the extra flow resistance near the wellbore. A negative skin means the near-wellbore region is less restrictive than normal, often due to stimulation or cleanup. Because the flow barrier is reduced, the well can draw fluid more easily, which is effectively like having a larger bore radius. That’s why describing negative skin as reducing the restriction and effectively increasing the bore radius fits best. The other ideas don’t align with what negative skin does: it doesn’t increase restriction, it doesn’t directly reduce reservoir pressure, and it does affect flow.

Skin describes the extra flow resistance near the wellbore. A negative skin means the near-wellbore region is less restrictive than normal, often due to stimulation or cleanup. Because the flow barrier is reduced, the well can draw fluid more easily, which is effectively like having a larger bore radius. That’s why describing negative skin as reducing the restriction and effectively increasing the bore radius fits best. The other ideas don’t align with what negative skin does: it doesn’t increase restriction, it doesn’t directly reduce reservoir pressure, and it does affect flow.