676 Subsurface Geologic Methods 



the same optical system in reverse for projection printing or projection 

 viewing of the developed film. One rather simple method of taking pic- 

 tures in different directions would be to use a plane 45° mirror as in the 

 present camera but to provide a means, perhaps a motor or a solenoid, for 

 rotating the mirror progressively a slight distance around a vertical axis 

 each time the film is advanced. 



Stereoscopic Pairs 



Related to the problem discussed above is the one of taking pictures 

 in stereoscopic pairs for stereoscopic viewing. The sense of perspective 

 offered in this way should be useful in studying the porosity, cleavages, 

 and general structure of the formation. The usual method of taking the 

 views from slightly different lens positions would be applicable here. In 

 this case rotating the mirror is equivalent to shifting the lens position. 

 Thus for steroscopic pairs if would be necessary only to take two sepa- 

 rate pictures at each camera location, rotating the lens through a small 

 fixed angle between the two exposures. 



Another idea offering real possibilities is the one of replacing the 

 photographic camera with a television camera and transmitting to the 

 surface, where the subject viewed by the camera would be immediately 

 and continuously visible on a screen. This subject has been considered 

 by many. Wired-television techniques now being employed industrially for 

 the observation of remote locations should be applicable here. The Dia- 

 mond Power Specialty Corporation of Detroit is now engaged in develop- 

 ing a deep-well television device. It is believed that with present televi- 

 sion tubes and techniques such a development is entirely feasible. The 

 deep-well camera has been developed to the point at which it can be of 

 very practical value in examining bore holes. Developments in the near 

 future should make it even more valuable. 



THE ELECTRIC PILOT IN SELECTIVE ACIDIZING, PERMEABILITY 

 DETERMINATIONS, AND WATER LOCATING 



P. N. HARDIN 



The three major uses for the electric pilot in oil-field completions and 

 remedial work are in selective acidizing, permeability surveys, and water- 

 locating surveys. Selective acidizing is employed to control the injection of 

 acid into specific sections of the well bore during the acidizing of a well, 

 thus increasing the permeability of these sections without affecting the 

 permeability of other exposed zones. Permeability surveys are made to 

 determine the thickness of the various permeable sections of the bore hole, 

 the vertical position of these zones at the bore hole, and the relative capa- 

 cities of the individual zones. Water-locating surveys are conducted to 

 determine the points of entry of formation waters into a well. 



