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Brief Notes on Field Methods Used in Geological Work 

 OF Mid-Continent Oil Fields. 



Louis Roark — Indiana University. 



In writing this article the writer is not attempting to make an 

 elaborate discussion of the various methods nor is he attempting to 

 suggest new methods of doing field work, but instead is endeavoring to 

 bring together in a compact form, various methods commonly used, for 

 the benefit of the young geologist who has not had an opportunity to 

 learn them by actual experience. 



No doubt many will take issue with me in regard to the value of 

 some of these methods. However the writer has found them quite satis- 

 factory under certain conditions and within certain limitations. 



The geological work as conducted by the different oil companies 

 of the mid-continent field is based upon one fundamental principle, 

 namely, the location of structure favorable to the production of oil. 

 The favorable structure as all know is the anticline. Therefore the 

 geologist is continually searching for the anticline. 



The geologist meets with many and varied difficulties in this work. 

 He must follow the outcrops of the various rock strata and obtain eleva- 

 tions at intervals of at least one quarter mile and oftener if necessary. 

 He must also measure the vertical interval between the different strata 

 whenever the two horizons outcrop close together, thus presenting an 

 opportunity to make such measurement. This vertical interval should 

 be measured frequently in order to catch any variation in the interval. 

 These elevations and intervals are used as a basis for drawing the 

 structural contours, thus enabling the geologist to select the most fa- 

 vorable locations for drilling. 



The following methods are used to obtain the elevation of outcrops. 



1. Plane Table and Stadia Traverse, Using Telescopic Alidade. 



2. Setting Bench Marks with Plane Table and Stadia. Geologist 

 Using Aneroid Barometer. 



3. Using Aneroid Barometer v/ith Stationary Barograph. 



