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EXAMINATION OF 

 WELL CUTTINGS 



Julian W. Low 



INTRODUCTION A few years ago the principal work of the 



oil geologist consisted in finding and map- 

 ping a surface geologic structure by means of the plane table and measuring 

 a surface stratigraphic section. If wells had been drilled in the immediate 

 vicinity, samples were examined in a cursory fashion for the purpose of estimat- 

 ing the depths to objective horizons. Many of the wells were drilled without 

 benefit of geologic appraisal of the area, and no representative samples were 

 saved for later study. Little or no thought was given to subsurface work as a 

 principal tool of exploration. 



Today, the petroleum geologists of most regions are concerned primarily 

 with subsurface geology and the main source of subsurface geologic data — well 

 samples and cores. The quality of well cuttings has steadily improved as a result 

 of better drilling practices, and this development has encouraged a greater 

 emphasis on subsurface methods. The geomicroscopist now occupies a foremost 

 position in the search for new oil fields. Surface field geology still maintains an 

 important position, but it is now often used as a supplement to the more highly 

 regarded subsurface geology. 



The man working with well samples is constantly confronted with two 

 problems which largely govern his daily activities. They are quality of work 

 and quantity of production. In petroleum geology these two factors must be 



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