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. 19, 1994
Filed:
Nov. 24, 1992
Shu-Kong Chang, West Redding, CT (US);
Chaur-Jian Hsu, Danbury, CT (US);
Schlumberger Technology Corporation, New York, NY (US);
Abstract
The present invention offers methods and apparatus for low-frequency sonic borehole logging with tube waves using discrete frequency measurements. A source transducer emits sonic energy at a location in a borehole of at least one discrete frequency which induces propagation of tube waves in the borehole; sonic energy of the tube waves is received at multiple receiver locations in the borehole, the multiple receiver locations being spaced apart from one another and from the source transducer location; and at each said receiver location, the complex pressure response (amplitude and phase, or real and imaginary parts) of a receiver to the received sonic energy of the tube waves is detected relative to a phase reference. The detected complex pressure response may be processed to determine phase velocity of the tube waves in the borehole as a function of frequency, to determine attenuation of the tube waves in the borehole as a function of frequency and/or to determine attenuation and amplitude as functions of frequency. In addition, tube wave reflection coefficients near fractures, bed boundaries, etc., may be calculated. The tube wave data are useful for permeability correlation, fracture evaluation, rock rigidity studies and other purposes.