Development and successful testing of a continuous wave logging-while-drilling telemetry system

Conference · Thu Jan 01 04:00:00 EST 1976

OSTI ID:7308066

Patton, B J; Gravley, W; Godbey, J K; Sexton, J H; Hawk, D E; Slover, V R; Harrell, J W

A continuous wave logging-while-drilling telemetry system capable of transmitting five down-hole measurements per foot at a penetration rate of 180 ft/hour with 10-bit precision and with adequate depth range under most drilling conditions was successfully tested during 1971. A logging-while-drilling service (utilizing this telemetry system) is currently being developed for commercial application by a major service company. The down-hole unit was housed in a 7-in. OD by 17-ft-long drill collar just above the bit. The unit consisted of a 500-w mud turbine-driven alternator, an electronic package, and an electric motor-driven rotary valve. The rotary valve generated a digitally encoded, phase-modulated, continuous pressure-wave signal in the mud inside the drillstring. The signal traveled at about 4,300 ft/sec through the drilling fluid to the surface and was detected by a pressure transducer mounted near the swivel. The signal was decoded and the values of the measurements tabulated on a teletype. The objective of the field test program was to demonstrate transmission capability of the system. Error-free transmission was obtained during several field tests at depths up to 12,000 ft. The field tests also provided information to confirm signal attenuation and depth-range theory, which enables prediction of depth range and data rate capabilities for any set of drilling conditions. Depth range is more than adequate in low-viscosity drilling fluids; however, high-viscosity drilling fluids may limit depth range to 14,000 to 17,000 ft. Sixteen channels of data were multiplexed and transmitted including mud temperature, tool vibration, alternator speed and internal parameters of the telemetry system. In commercial service, the system will be adaptable to the transmission of any down-hole measurement including hole direction, tool-face orientation, formation properties, drilling variables, and bottom-hole conditions.

• OSTI ID: 7308066
• Report Number(s): CONF-761008-96
• Country of Publication: United States
• Language: English

Related Subjects

02 PETROLEUM
020300* -- Petroleum-- Drilling & Production
ACOUSTIC MONITORING
COMMUNICATIONS
DATA TRANSMISSION
DESIGN
DRILLING
EQUIPMENT
MONITORING
PERFORMANCE
TELEMETRY
WELL DRILLING