Borehole acoustic telemetry system with phase shifted signal

Patent · Tue Dec 31 04:00:00 EST 1985

OSTI ID:5866456

Sharp, H E; Smither, M A

In a borehole telemetry system for acoustically transmitting data over a pipe suspended in a borehole, the level of noise in the data stream is inherently high due to the environment existing in a drilling operation and to the physical characteristics of a drill string. It has been discovered that certain discrete frequency passbands exist in a drill string which permit transmission of an acoustic signal with a minimum level of attenuation. In addition, it is now known that a fine structure exists within these frequency passbands which present gaps or voids that attenuate the signal at a much higher rate. These gaps are on the order of 20 Hz. By generating an acoustic signal at a precise frequency spectrum within these passbands and then phase shifting the signal before its transmission, the energy spectrum of the transmitted signal is spread out over a sufficient frequency range to bridge these gaps.

• Assignee: NI Sperry Sun Inc.
• Patent Number(s): US 4562559
• OSTI ID: 5866456
• Country of Publication: United States
• Language: English

Related Subjects

02 PETROLEUM
020300* -- Petroleum-- Drilling & Production
ACOUSTICS
COMMUNICATIONS
CONTROL
DATA TRANSMISSION
DESIGN
DRILL PIPES
DRILLING EQUIPMENT
ENERGY SPECTRA
EQUIPMENT
FINE STRUCTURE
FREQUENCY CONTROL
FREQUENCY RANGE
MWD SYSTEMS
OIL WELLS
PHASE SHIFT
PIPES
SONIC LOGGING
SOUND WAVES
SPECTRA
TELEMETRY
WAVE PROPAGATION
WELL LOGGING
WELLS