Page 451 - Practical Well Planning and Drilling Manual

Section 3 revised 11/00/bc 1/17/01 12:00 PM Page 427

3.7.5
Directional Drilling [ ]

This verifies that there is film ready to load into the camera. Open the
camera gate, push the film magazine loading lever in, and close the
camera gate. Check that the indication is “loaded” on the camera gate
closing ring; then, if all is OK, remove the film magazine. The camera
is now ready to use.
Attach the bottom of the camera to the rubber shock absorber
inside the survey outer barrel. Switch on the timer or motion sensor,
make up the outer barrel with 18 in pipe wrenches. If running on wire-
line make up to the line, otherwise drop down the drillstring. Keep
working the string until either the survey on wireline reaches bottom
or until a minute before the timer goes off (less if the hole is sticky).
Position the bit about 2 m off bottom and wait until either: 1 minute
after the timer was due to go off, or 1 minute 40 seconds after the
monel detector reached bottom, or 1 minute 40 seconds after the string
was stopped off bottom with the motion sensor. Note that the exposure
time is 1 minute.
In sticky hole conditions, it is good practice to stop moving the
string on a down stroke about 5-10 ft off bottom. When the survey has
been taken, move down initially and ensure that the string is free
before picking up. If the string has started to get stuck, moving down
will tend to free it, whereas picking up may embed the string further.
Developing the survey. When the survey barrel is recovered,
undo the outer barrel and recover the camera complete. Remove the
drillfloor. Prepare the developing tank by making sure it is clean;
reassemble it and pour developing fluid into the top until it is exact-
ly level with the top—no more, because it will drain through into the
developing chamber.
Hold the camera unit horizontally (no need to remove the angle
unit) and place the developing tank entry against the camera loading
gate so the pins are located in the holes and a light tight connection is
made, with the developing tank underneath. Open the camera gate;
the film can be heard as it drops into the chamber. Pull up the top part
of the developing tank and the film will drop right through to the
developing chamber.
Put the camera down, hold the developing tank upright, and shake
gently for one minute. Open the top, remove the film, and wash in run-
ning water. The film can be examined with the magnifying examiner.

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