Miscellaneous Subsurface Methods 



583 



instrument to the well on which it is run. No instrument watch is photo- 

 graphed by the lights which are supplied current from flashlight batteries. 

 An exceptionally accurate, synchronized surface clock is used to number 

 the pictures taken. The instrument is mounted in its barrel between springs 

 and rubber shock absorbers to protect it from vertical shock. 



In use, the machine is started in exact synchronization with the sur- 

 face clock and placed in its barrel. The barrel is lowered on a wire line 

 or dropped into the drill pipe when the driller is ready to take the pipe 

 from the hole to change bits. The instrument barrel is of correct length 



CSC^-^'CS t:_ 



Figure 304. Experimental l^/i-inch multiple-shot machine disassembled. 



to position the compass in the angle unit in the center of a length of K- 

 Monel drill collar, which is in the drilling string immediately above the 

 bit. After the survey equipment has reached bottom, the pipe is withdrawn 

 from the well. A magnetic survey is made by taking a reading as each 

 stand of drill pipe is unscrewed and set back. Usually an extra minute of 

 time is taken for each stand over and above the normal pull-out time. No 

 special round trip of the drill pipe is made in order to survey the well. 



This same machine was used to make an oriented survey on sucker 

 rods inside of two-inch upset tubing in a well in which the tubing was 

 stuck. 



It is contemplated that further development will produce an instru- 

 ment by which an oriented survey can be made as the pipe is withdrawn 

 from the well in much the same manner as described above for running 

 magnetic surveys. Perhaps the equipment will be perfected to be lowered 



