Define Positive skin.

Define Positive skin.

• A. A decrease in the flow rate near the well
• B. An increase in the reservoir temperature near the well
• C. A change in rock color near the well
• D. Any phenomenon that causes a distortion to the flow lines from the perfectly normal to the well direction or a restriction to flow.

Answer: (D)

Positive skin is a near-wellbore condition that adds extra resistance to flow toward the well, represented by a positive skin factor in radial reservoir flow. This means the flow lines near the well become distorted or redirected, and the near-well region restricts flow, increasing the pressure drop for a given production rate. The description that captures this idea best is that it encompasses any phenomenon that causes the flow lines to deviate from their normal pattern toward the well or creates a restriction to flow near the well. A decrease in flow rate near the well can happen as a result of positive skin, but it’s the near-well flow distortion or restriction itself that defines positive skin. Changes in temperature, rock color, or other surface observations are not defining features of skin.

Positive skin is a near-wellbore condition that adds extra resistance to flow toward the well, represented by a positive skin factor in radial reservoir flow. This means the flow lines near the well become distorted or redirected, and the near-well region restricts flow, increasing the pressure drop for a given production rate. The description that captures this idea best is that it encompasses any phenomenon that causes the flow lines to deviate from their normal pattern toward the well or creates a restriction to flow near the well. A decrease in flow rate near the well can happen as a result of positive skin, but it’s the near-well flow distortion or restriction itself that defines positive skin. Changes in temperature, rock color, or other surface observations are not defining features of skin.