Patent ID: 9651699
Date: 2017-05-16
CPC Classifications: G01V

Claim:
1. A method for characterizing subsurface formations penetrated by a wellbore, comprising: accepting as input to a computer measurements of a physical parameter of the formations made over a selected axial interval of the wellbore; in the computer calculating at least one attribute of the measurements (measured values) from a change in the measurements over the selected axial (depth) interval, wherein the attribute is directly related to a shape of a curve defined by the change in measurements over the selected axial interval, wherein the calculating the at least one attribute comprises at least one of (i) determining a slope of a best fit line through a shallowest axial intersection of a progressively decreasing threshold value and the measurement values in a single cycle exceeding the progressively decreasing threshold value, (ii) determining a slope of a best fit line through a deepest axial intersection of a progressively decreasing threshold value and the measurement values in a single cycle exceeding the progressively decreasing threshold value, and (iii) determining a slope of a best fit line through a midpoint (average) of a shallowest and a deepest axial intersection of a progressively decreasing threshold value and the measurement values; and in the computer determining a characteristic of the formations in the selected axial interval using the at least one attribute, wherein the characteristic is related to the defined shape.