Abstract:

Basing on the chart analysis for clay mineral content, a cross plot of clay mineral content and radioactivity element concentration was obtained, and a multivariate linear relation between clay mineral content and radioactivity element U, Th and K was established, deriving a regression equation to estimate clay mineral content. Through the regression analysis of the data from different well sections or the same well section of different formations, a typical linear regression model was provided. The application of the model to a real well section got a vertical variation of clay mineral, which was in an excellent agreement with the practical interpretations.

Key words: natural gamma-ray logging, clay minerals, chart analysis, regression equation