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Title: Application of the spread-spectrum technique in well logging

Abstract

This paper presents the novel concept of employing the noise insensitive spread-spectrum technique in well logging. The proposed design of a spread-spectrum device improves the performance of well logging tools, particularly within highly noisy environments. The heart of the device is a shift register which generates a pseudorandom binary code sequence. A coder is connected to the transmitter and codes the probing signal by utilizing the pseudorandom sequence. A decoder is connected to the receiver and correlates the return signal to the same sequence, which is used as a sliding reference. Shifts as small as a fraction of a bit are unambiguously resolvable, and distance resolution of the order of micrometers is achievable. Spread-spectrum well logging tools can operate even with coded signal-to-noise ratio below zero-dB. The spread-spectrum device can be interfaced with any available wave transmitting logging tool. However, tools employing acoustic waves are favorable because the acoustic wave propagation velocity is low and allows the use of inexpensive electronics. The problems associated with high temperatures which are commonly encountered In geothermal reservoirs are bypassed, since the spread-spectrum device can be located either inside the well logging tool or together with the supporting electronics on the surface.

Authors:
;
Publication Date:
Research Org.:
Stanford University, Stanford, CA
Sponsoring Org.:
USDOE
OSTI Identifier:
887297
Report Number(s):
SGP-TR-113-42
DOE Contract Number:  
AS07-84ID12529
Resource Type:
Conference
Resource Relation:
Conference: Proceedings, thirteenth workshop on geothermal reservoir engineering, Stanford University, Stanford, CA, January 19-21, 1988
Country of Publication:
United States
Language:
English
Subject:
Geothermal Legacy

Citation Formats

Chrysikopoulos, Constantinos V, and Dadakarides, Simos D. Application of the spread-spectrum technique in well logging. United States: N. p., 1988. Web.
Chrysikopoulos, Constantinos V, & Dadakarides, Simos D. Application of the spread-spectrum technique in well logging. United States.
Chrysikopoulos, Constantinos V, and Dadakarides, Simos D. Fri . "Application of the spread-spectrum technique in well logging". United States. https://www.osti.gov/servlets/purl/887297.
@article{osti_887297,
title = {Application of the spread-spectrum technique in well logging},
author = {Chrysikopoulos, Constantinos V and Dadakarides, Simos D},
abstractNote = {This paper presents the novel concept of employing the noise insensitive spread-spectrum technique in well logging. The proposed design of a spread-spectrum device improves the performance of well logging tools, particularly within highly noisy environments. The heart of the device is a shift register which generates a pseudorandom binary code sequence. A coder is connected to the transmitter and codes the probing signal by utilizing the pseudorandom sequence. A decoder is connected to the receiver and correlates the return signal to the same sequence, which is used as a sliding reference. Shifts as small as a fraction of a bit are unambiguously resolvable, and distance resolution of the order of micrometers is achievable. Spread-spectrum well logging tools can operate even with coded signal-to-noise ratio below zero-dB. The spread-spectrum device can be interfaced with any available wave transmitting logging tool. However, tools employing acoustic waves are favorable because the acoustic wave propagation velocity is low and allows the use of inexpensive electronics. The problems associated with high temperatures which are commonly encountered In geothermal reservoirs are bypassed, since the spread-spectrum device can be located either inside the well logging tool or together with the supporting electronics on the surface.},
doi = {},
journal = {},
number = ,
volume = ,
place = {United States},
year = {1988},
month = {1}
}

Conference:
Other availability
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