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DIPMETER 

 SURVEYS 



E. F. Stratton 



and 



R. G. Hamilton 



The SP (spontaneous-potential) dipmeter was described in 1943 by H. G. 

 Doll as a means for determining the direction and magnitude of formation dip 

 in situ. This instrument was designed to record simultaneously three SP curves 

 of known orientation, 120° apart along three generatrices of a well bore. Each 

 curve fixes thus one point on a bedding surface and the position of the surface 

 can be determined (fig. 19-1) by the displacement between the curves. 



It was thought desirable in some areas to record 3 resistivity curves instead 

 of 3 SP curves. Accordingly, the design and development of a resistivity dip- 

 meter was undertaken. The availability of a resistivity dipmeter, in addition to 

 the SP dipmeter, has extended appreciably the application of the procedure. 

 Some 6 or 7 thousand dipmeter levels, SP and resistivity, now have been 

 recorded in wells throughout most of the major oil provinces in the country and 

 in many foreign fields. It seems advisable to analyze these data and to describe 

 their application to some of the problems that have been encountered in ex- 

 ploration and development work. 



The hole assembly, about 25 feet long, consists of a mandril to which are 

 attached three hard-rubber arms spaced 120° apart; in the center of each arm 

 and positioned on the same plane at right angles to the axis of the instrument is 

 one of the three recording electrodes. Attached to the electrode unit is a photo- 

 clinometer, which determines photographically the orientation of each of the 



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