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Title: Reducing injection loss in drill strings

Patent ·
OSTI ID:1175038

A system and method for transferring wave energy into or out of a periodic structure having a characteristic wave impedance profile at a prime frequency, the characteristic wave impedance profile comprising a real portion and an imaginary portion, comprising: locating one or more energy transfer elements each having a wave impedance at the prime frequency approximately equal to the real portion of the characteristic wave impedance at one or more points on the periodic structure with the imaginary portion approximately equaling zero; and employing the one or more energy transfer elements to transfer wave energy into or out of the periodic structure. The energy transfer may be repeaters. Quarter-wave transformers can be provided at one or more points on the periodic structure with the imaginary portion approximately equaling zero to transmit waves across one or more discontinuities. A terminator can be employed for cancellation of waves. The invention substantially eliminates reflections of the wave energy at the prime frequency by joints between sections of the periodic structure.

Research Organization:
Sandia National Lab. (SNL-CA), Livermore, CA (United States)
Sponsoring Organization:
USDOE
DOE Contract Number:
AC04-94AL85000
Assignee:
Sandia Corporation
Patent Number(s):
6,791,470
Application Number:
09/872,907
OSTI ID:
1175038
Country of Publication:
United States
Language:
English

References (5)

Passbands for Acoustic Transmission in an Idealized Drill String journal May 1972
Extensional stress waves in one‐dimensional elastic waveguides journal December 1992
The propagation of sound waves in drill strings journal April 1995
Attenuation of sound waves in drill strings journal October 1993
Acoustical properties of drill strings journal March 1989