8 Subsurface Geologic Methods 



with the basic lithologic varieties and logging methods, should be assigned 

 a well section to log. This work involves the examination and plotting of 

 a lithologic log from ditch cuttings and cores. The lithology should first 

 be plotted on a percentage basis, and subsequently the lithic boundaries 

 should be adjusted and an interpretive log prepared. Color symbols 

 should be used to represent lithologies (pi. 11). In addition to interpret- 

 ing and recording the lithologic sequence of a well, each student should 

 have available an electric-log profile with which to make comparisons. 

 Upon completion of the log a final report of the well should be required. 



Contouring: Several electric-log series from oil fields should be 

 studied and correlated, and subsurface structural and isopachous maps 

 prepared. Cross sections should also be incorporated. In addition to this 

 problem, a number of theoretical contour problems should periodically 

 be submitted to the class to improve structural interpretation. 



Correlation: Paired electric, radioactive, and lithologic logs from 

 various fields should be correlated in detail, and the results carefully 

 drafted and discussed. 



Principles of Stratigraphy and Correlation: The fundamental con- 

 cepts of stratigraphy and correlation should be treated and should include 

 such topics as facies changes, unconformities, onlaps and offlaps, and any 

 other criteria that control the correlation of strata. 



Laboratory Methods: The various techniques followed in subsurface 

 or stratigraphic laboratories should be broadly outlined and reviewed and 

 should include such topics as detrital mineralogy, insoluble residues, stain 

 tests, micropaleontology, and thin-section, screen, and sedimentation an- 

 alyses. 



Miscellaneous Topics: Such topics as directional drilling, acidizing, 

 cementing, secondary recovery, formation testing, and coring should be 

 briefly reviewed with emphasis placed on the geologic aspects. 



In the graduate school more specialized subsurface problems should 

 be emphasized. The subject matter should include structure contouring, 

 fault problems, correlation interpretation, paleogeologic and lithofacies 

 mapping, isopachous studies, and the preparation of subsurface geologic 

 reports. These courses should be presented with the intention of intro- 

 ducing to the student the "work pressure" factor that prevails in eco- 

 nomic programs. 



Those students having a geologic-engineering background are fa- 

 vorably adapted for subsurface geologic investigation. This does not 

 imply that such training is essential to develop good subsurface person- 

 nel; it cannot be denied, however, that the basic sciences of mathematics, 

 physics, chemistry, hydraulics, thermodynamics, and descriptive geometry 

 provide favorable attributes. 



To train an individual for subsurface geology as applied today in 

 the petroleum industry should require at least eight years after termina- 

 tion of hia advanced academic work. A minimum of two. years in surface 



