-CUSHON OK BWTIALLy 

 flLLIO DRILL PIPE 

 TO PRtVENT COLLAPSE 



•TMOSPHEmC 

 PRESSURE 

 (ZERO GAUGE) 

 Cfl CUSHION 

 PRESSURE 



aTMOSPHERIC 

 OR CUSHION 

 rRESSURC 



Figure 392. Operational sequence of a formation tester: (1) going in hole; (2) 

 packer set and tool open; (3) packer set and tool closed; (4) packer being 

 unseated. 



