What effect does increasing the angle of slant of a well have on skin?

What effect does increasing the angle of slant of a well have on skin?

• A. The larger the angle of slant the larger the negative contribution to the total skin effect.
• B. The larger the angle of slant the larger the positive contribution to skin.
• C. Angle has no effect on skin.
• D. Skin becomes unstable with increased angle.

Answer: (A)

Skin factor measures the extra pressure drop in the near-well region; a negative skin means the near-well flow is being stimulated or enhanced. When the well is more slanted, the flow path in the near-well zone often uses a larger portion of the reservoir surface and benefits from improved drainage, with gravity aiding the movement of fluids toward the well. This reduces localized losses, so the near-well contribution to the total skin becomes more negative. In other words, increasing the angle of slant makes the favorable (negative) skin larger, improving apparent well productivity. The other ideas—that angle has no effect, that it makes skin worse, or that it makes skin unstable—don’t align with how directional drilling can enhance near-well flow and reduce pressure losses.

Skin factor measures the extra pressure drop in the near-well region; a negative skin means the near-well flow is being stimulated or enhanced. When the well is more slanted, the flow path in the near-well zone often uses a larger portion of the reservoir surface and benefits from improved drainage, with gravity aiding the movement of fluids toward the well. This reduces localized losses, so the near-well contribution to the total skin becomes more negative. In other words, increasing the angle of slant makes the favorable (negative) skin larger, improving apparent well productivity. The other ideas—that angle has no effect, that it makes skin worse, or that it makes skin unstable—don’t align with how directional drilling can enhance near-well flow and reduce pressure losses.