Subsurface Logging Methods 



479 



Formerly the drilling time was obtained by stripping the kelly in ten-, 

 five-, or one-foot segments, depending upon the degree of control desired, 

 and recording the time as each mark reached the kelly bushing. Within 

 the last decade mechanical recorders have been developed which not only 

 are much more accurate in timing but are designed to show additional 

 relevant data such as the depth of the hole and the time consumed in 

 making connections, round trips for bit changes, and down time for 

 repairs. 



IMPODTAIsIT 



LINE FROM WEIGHT 

 GOES THRU CLOCK SIDE 



CU^x eOOSINECK 



l|)lAO MAN 



Figure 223. Schematic drawing of "Geolograph hook-up. 



