The Tele Concept
Teledrift speeds drilling by providing almost instantaneous surface
recordings of hole deviations without making round trips or running
wire lines.
The unit, which is operated by rig
personnel, is a 
rugged, stainless steel, mechanical device which measures well-bore angle in
one-half degree increments and transmits the information to an electronic recorder via mud pulse
telemetry. The first patents on mud
pulse telemetry were issued for the Teledrift instrument, thus making it
the Original MWD.
The Teledrift gives readings in one-half degree (1/2 degree)
increments or it can also be configured to measure in one-degree (1 degree) increments. The latter has a tool range of seven degrees (7
degrees) without re-setting the instrument. paragraphs on description of services.
How Teledrift Works
The Teledrift tool consists of a pendulum at the bottom that moves along a series of graduated stop
shoulders, and a signaling plunger at the top that traverses a series of seven annular restrictions to
produce pressure pulses in the mud stream. Plunger travel is controlled by a patented coding system so that deviation of the hole from the vertical increases
the number of pulses generated. A maximum of seven signals can be generated, each representing
an increment of hole angle of one-half degree. The tool can be quickly field-adjusted to measure any seven successive incremental angles of deviation up
to 10-1/2 degrees.
Making Teledrift Readings
Teledrift readings can be made any time during 
drilling. When drilling is stopped during both the measuring and the signaling
periods,
maximum downtime is generally 5 to 6 minutes. Downtime may be reduced to
only 3 to 4 minutes by resuming drilling during the signaling
period. For maximum clarity of signals, take readings between connections, when the mud is
very fluid, with no air in the pipe. Downtime may also be minimized by measuring the drift angle just
before making a connection and receiving the signals after completing the connection, when the pump is started. 
The most reliable operation is obtained by making the angle
measurement and recording signals in one unbroken sequence
between connections. This produces maximum signal clarity with minimum possibility of errors.
