Figure 25-15. Possible intersections of double cones of bedding plane normals in non- 

 parallel boreholes (Phillips). 



represent respectively two, three, and four possible answers to the problem of 

 two nonparallel boreholes. 



Selection of the correct dip and strike may sometimes be made from 

 general knowledge of the area, but if a third borehole is available, the un- 

 certainty is usually removed. For this procedure refer to Phillips, 1954. 



Determination of Correct- Dip by Use of Third NonparaiieS Drillhole (12) 



In the above example, we shall assume a third hole C, plunging 35 degrees 

 on azimuth 160 degrees. The measured dip in the core is 16 degrees. 



549 



