628 



Subsurface Geologic Methods 



of the second-shallowest level, and the procedure noted above is repeated. 

 Other levels are recorded in the same manner. 



After the deepest level has been recorded, it is resurveyed with a 

 photoclinometer picture taken in the middle of the level as well as at the 

 top and base. Each of the higher levels, similarly, is repeated as the 

 equipment is withdrawn from the hole. 



Interpretation 



All dipmeter surveys are analyzed by a staff specializing in such 

 work, and two independent interpretations are made for each operation. 

 Likewise, the data from the original and check runs on each level, gen- 

 erally recorded with different electrode orientations, must agree, or the 

 results are discarded. After the orientation of the curves, their displace- 



Figure 328. Typical dipmeter computation sheet. 



ment, and the drift and azimuth of the well bore have been determined 

 over the interval of a level, the magnitude and direction of the dip are 

 obtained quickly by mechanical means. 



A typical computation sheet is shown in figure 328. The first column 

 designates the level; Al, for example, is the original run, A2 the check 

 run, etc. The second column gives the depth interval of the level. The 

 third column shows the azimuth of the well in degrees from magnetic 

 north; the fourth column the drift angle. The fifth column is the position 

 of the No. 1 recording electrode in degrees from magnetic north. The 

 sixth and seventh columns indicate the displacement in inches of curves 



