Tornado Chart Sensitivity Analysis

$10.00

Jerry L. Jensen, Michael L. Gartner,
Gearhart Industries

SPWLA TWENTY-FOURTH ANNUAL LOGGING SYMPOSIUM, JUNE 27-30, 1983

1983

Abstract

The well logging industry has traditionally provided a variety of dual induction-resistivity tornado charts in their interpretive packages. These charts have been produced based on assumptions regarding the nature of the logging tool and its environment. When the actual situation deviates from the assumed conditions, no indi- cation is given as to how large the errors in interpreted values might be. This study assesses the changes in interpreted values for the diameter of invasion (d.) and the ratio of flushed-zone to vir- gin-zone resistivities (Rxoht) arising from the use of different tornado charts.