1076 



EXPLORATION GEOPHYSICS 



Another example, Figure 669, shows the relation between thermometric 

 measurements and photoelectric recordings on the same well. The ther- 

 mometric data for this well have already been discussed. After obtaining 

 the temperature anomaly between 3913 and 3945 feet, that section of the 

 hole was conditioned by dumping several barrels of mud through the 

 interval. The photoelectric instrument was then lowered into the well. 

 A translucency versus depth graph (curve 1) obtained immediately after 

 the conditioning run showed that 150 feet of translucent water had entered 

 the hole. (Note that the water was entering at 3915 feet and going down.) 

 The instrument was pulled up, and 45 minutes later it was again lowered 





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iv/)r/:/? £rA/r£:/?/A/<7 r/?oAi sorrow 



CAS/A/G £>s/>r.>^ ■f/7ts' rorA/. £>£r/=7-// -fJZfg 



Fig. 670. — Photoelectric survey. Graph shows that water entered 

 at bottom of well from exposed formation. 1, initial curve after con- 

 ditioning well; 2, 3, 4, curves after formation water entered well. 

 (Dale and Deleney, Personal Communication.) 



through the zone (curve 2). This curve showed 500 feet of clear fluid, 

 and hence indicated a rate of flow of at least 400 feet per hour. This 

 quantity of water entering at 3900 feet and going down into the pro- 

 ducing formation would soon have flooded not only this one well but also 

 the nearby producing wells had it not been shut off by cementing. 



Correlation of Oil Well Waters 



An analysis of the salts of oil well waters oftentimes allows correlating 

 the waters with regard to their origin, t Oil well waters commonly contain, 

 in addition to various other elements, lithium, sodium, potassium, calcium, 

 strontium, and barium. The procedure is as follows : Well waters arc 

 evaporated to dryness and the residue volatilized in a direct current car- 

 bon arc. The light emitted 1:)y the arc is photographed by a grating 

 spectrograph.* 



t M. F. Hasler, "The Spectrographic Correlation of Oil Well Waters," Geophysics, Vol. 2, 

 No. 2, March 1937, pp. 127-131. 



J. S. Ross and E. A. Swedenborg, "Analysis of Waters of the Salt Field Applied to Under 

 ground Problems," A.I.M.E. Petroleum Technology, 1928-29. 



* A grating spectrograph comprises a slit, a lens, a grating, and a camera. The 

 camera records the "spectral lines," i.e., images of the slit, characteristic of the 

 "excited" substances — in this case, the elements present in the salts. 



