Named for the weather phenomenon which it resembles, what type of plot is used to correct deep log resistivity to true formation resistivity?

• A. Rainfall Plot
• B. Wind Speed Chart
• C. Storm Diagram
• D. Tornado Chart

Answer: (D)

Sensitivity plots that resemble a weather funnel are used to show how uncertainty in input parameters influences a calculated result. The tornado chart does exactly that: each horizontal bar represents an input, and the length shows how much the corrected resistivity could change as that input varies within its plausible range. This visualization makes it clear which factors most affect the true formation resistivity, so you know where to focus measurement accuracy and control. The weather-named options aren’t standard plots for this purpose, so they don’t fit the way a tornado chart does in illustrating input influence on the resistivity correction.