US 4,542,648 A · Method of correlating a core sample with its original position in a borehole

Abstract

A method of correlating a core sample with its original position in a borehole. The borehole is logged to determine the bulk density of the formation surrounding the borehole. The core sample is scanned with a computerized axial tomographic scanner (CAT) to determine the attenuation coefficients at a plurality of points in a plurality of cross sections along the core sample. The bulk density log is then compared with the attenuation coefficients to determine the position to which the core sample correlates in the borehole. Alternatively, the borehole can be logged to determine the photoelectric absorption of the formation surrounding the borehole, and this log can be compared with data derived from scanning the core sample with a CAT at two different energy levels.

Claims11

Dependent claims

A method of correlating a core sample with its original position in a borehole, said method comprising the steps of:

logging the borehole to determine the bulk density of the formation surrounding the borehole;
scanning the core sample with a computerized axial tomographic scanner to determine the attenuation coefficients at a plurality of points in a plurality of cross sections along said core sample;
comparing the bulk density log determined in said logging step with the plurality of attenuation coefficients determined in said scanning step to determine the position to which said core sample correlates in said borehole.

A method of correlating a core sample with its original position in a borehole, said method comprising the steps of:

logging the borehole to determine the photoelectric absorption of the formation surrounding the borehole;
scanning said core sample with a computerized axial tomographic scanner (CAT) at a first energy to determine the attenuation coefficients at a plurality of points in a plurality of cross sections along said core sample at said first energy;
scanning said core sample with a CAT at a second energy to determine the attenuation coefficients at said plurality of points in said plurality of cross sections along said core sample at said second energy;
using the attenuation coefficients determined for said core sample at said first and second energies for said plurality of points in said plurality of cross sections along said core sample to determine the effective atomic numbers for said plurality of points in said plurality of cross sections along said core sample;
comparing the photoelectric absorption log determined in said logging step with the effective atomic numbers determined in said using step to determine the position to which said core sample correlates in said borehole.

2 more elements

Dependencies are inferred from the claim text.

Method of correlating a core sample with its original position in a borehole

Life of this patent

Method of correlating a core sample with its original position in a borehole

Life of this patent

Abstract

Claims11