The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Feb. 16, 1982
Filed:
Jul. 28, 1980
Eric C Hopkinson, Houston, TX (US);
Dresser Industries, Inc., Dallas, TX (US);
Abstract
A pulsed source of fast neutrons and a radiation detector system are utilized in a well logging instrument, the detector being responsive to the thermal neutron population decay rate. The inverse of the decay rate is proportional to the measured macroscopic neutron absorption cross-section (Sigma) of the surrounding formations. A first Sigma is measured by taking the natural logarithm of the ratio of the detected radiation counts occurring within two measurement intervals. A second Sigma is measured by taking the natural logarithm of the ratio of the detected radiation counts occurring within a second pair of measurement intervals. The first Sigma value is recorded when the Sigma value falls below a preselected limit and the second Sigma value is recorded when the formation Sigma value is above the preselected limit. Thus, the Sigma log is a composite of the two Sigma measurements.