Butterfly chart

{
  "id": "MLC-T-OAG-004250",
  "term": "Butterfly chart",
  "field": "Oil and gas",
  "definition": "A graphical tool used to determine true formation resistivity and the diameter of invasion from dual-resistivity logging measurements, such as dual induction or dual laterolog tools. The chart consists of a family of curves representing different invasion diameters, plotted against the ratio of the deep to shallow resistivity readings. By plotting the measured resistivity ratio on the chart, an interpreter can find the corresponding correction factor to derive the true formation resistivity.",
  "subject": "Formation Evaluation",
  "url": "https://mlchart.com/terminology/oil-and-gas/butterfly-chart/"
}