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:
Jul. 01, 1986
Filed:
Feb. 24, 1983
Robert A Broding, Tulsa, OK (US);
Standard Oil Company (Indiana), Chicago, IL (US);
Abstract
Methods and apparatus are disclosed for measuring a length of logging cable introduced into a borehole, thereby measuring the depth of a logging tool, or sonde, attached to the lower end of the cable. The methods involve producing an electrical signal, which propagates along the cable, and detecting at the mouth of the borehole the time of passage of the initial electrical signal and the time of passage of a subsequent electrical signal reflected or returned upwardly from the lower end of the cable, or, alternatively, the time of arrival of the reflected or returned electrical signal at the upper end of the cable. These times can be determined by means of clocks which are switched on by the passage of the initial electrical signal and switched off by the subsequent electrical signal. Knowing the time intervals and the velocity of propagation of electrical signals in the cable, the length of cable from the mouth of the borehole to the lower end of the cable, and thus the depth of the sonde, is measured. Various embodiments of apparatus including electrical signal detectors which do not electrically contact the cable are disclosed for sensing the electrical signals necessary for measuring the length of cable introduced into the borehole, and thus the depth of the sonde.