Miscellaneous Subsurface Methods 



561 



rubber mud shield slipped over the barrel keeps the single shot clean as 

 it is unloaded from the barrel. 



The three-inch barrel is provided with top connections to fit large 

 diameter wire-line coring equipment when the instrument is run down 

 inside the drill pipe and out through the bit. (See description of the small- 

 type single shot below.) It is similar to the larger barrel. 



The regular single shot generally is run after the drill pipe has been 



Figure 282. Cutaway model of 90-degree-angle unit. 



removed from the well (fig. 286). The angle unit is unscrewed from the 

 instrument and the lights are checked to insure that they are operating. 

 After the angle unit is replaced, a disk is loaded into the machine with 

 the loader, and the contact-timing watch is set for the amount of time it 

 will take to run the instrument to the required depth in the well. The sur- 

 face watch (fig. 274) is set at exactly the same time for reference. The 



