INSTRUMENTAL SURVEY OF BOREHOLES 



53 



the old and tried method of acid etching is compared with 

 a recent plunger-pricker method for amount of dip only.^ 



Table VIII. — Comparative Surveys of an Oil Borehole in the 

 Seminole District, Oklahoma 



Depth, 

 feet 



Acid-bottle reading, 

 degrees, corrected 



However, these checks are relative and cannot be claimed 

 as absolute; the only absolute checks are actual observa- 

 tional ones as 



1. Where a hole is followed by a shaft or drift. 



2. A^Tiere a hole has been bored between known and 

 occupied places, as between stopes, working seams, etc. 



3. Where boreholes deviate and meet; all methods thus 

 registering the same meeting spot in both holes. 



^ Petroleum Engineer, December, 1929. 



