C&afit&i 29 



CONVENTIONAL 

 ROCK BITS 



L . L. Payne 



This discussion outlines some of the problems confronting the operator 

 in selecting proper bit types to accommodate various drilling conditions. 



In proved fields, bit performance, together with geological data from 

 adjacent completed wells, can and should be used in selecting bit types; how- 

 ever, quite often the operator has no definite information on wildcat drilling 

 and even in some proved areas where faults and abnormal dips occur in the 

 subsurface. In any event, if an operator is to drill a well economically, it is 

 important that the general purpose of the bit design and the various types of 

 bits be understood. 



KINDS OF BITS Figure 29-1 lists some of the more popular 



rock bits currently being used in drilling oil 

 wells, together with the most common rocks for which they were designed. In 

 addition, Figure 29-1 shows schematically a comparison of some of the im- 

 portant design features for the various bit types. 



It will be noted from Figure 29-1 that 10 groups of bit types are shown; 

 however, not all of these types should be used in drilling any one particular 

 well. Generally, three or four types should be sufficient; in some areas only one 

 or two types have been found adequate to drill economically a complete well. 



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