mates must be made at this stage of jet-bit development. The following discussion 

 will review the various cost factors pertaining to jet-bit operation on a typical 

 5000-foot drilling rig that operates at a cost of $1000 per day, plus the cost of 

 conventional bits. 



Cost of the Bit 



Compared to the conventional bit, the jet bit is premium-priced because of 

 the additional manufacturing cost of tungsten-carbide nozzles. 



2500- 



2000 



ISOO 



IOOO 



500 



-500 



tv 



ASSUMED DATA: 



DEPTH OF WELL-SOOO' 

 No CONV. BITS -12 

 DRILLING HP. CONV. -ISO 

 RIG COST CONV.-$IOOO/DAY 

 RIG COST JET -$IO57/0AY 



Dor' 30 40 SO oO 70 80 90 

 0/ 7o IMPROVEMENT FOR JET BITS COMPARED TO 

 ONVENTIONAL BITS 



Figure 30-5. Chart showing dollars lost or saved by jet bits per 5000 feet well as a function 

 of: (1) penetration rate improvement, when jet and conventional bit footage are 

 identical, and (2) improvement in footage per bit when jet and conventional penetration 

 rates are identical. 



660 



