862 



Subsurface Geologic Methods 



scale are basic requirements for all correlation charts. In the event a local 

 correlation compilation is involved, it is good practice to include a re- 

 gional summary correlation chart for comparison. Many well-correlation 

 charts show the electric- and radioactive-log profiles adjacent to the lithic 



SUBSURFACE OIL, GAS, ft 

 WATER SYMBOLS 



WELL SYMBOLS 



O Derrick 



\} Abandoned derrick 



O Drilling well 



"G)" Drilling well suspended 



-Q}" Abandoned drilling well 



-^ Abandoned drilling well with oil show 



Oil producer 



Shut in or suspended oil producer 



-^ Abandoned oil producer 



Well with gas show 



-0^ Gas producer 



{[} Shut in or suspended gas producer 



-ffi- Abandoned gas producer 



-ffi- Abandoned gas well with gas show 



-jp^ Oil and gas producer 



-•- Abandoned oil and gas producer 



Figure 434. Symbols commonly used on well maps and logs. It is common practice 

 to place subsurface symbols either to right or left of log column. 



O GaSj small amounts 

 OO Gas, strong showing 

 Oil smell, faint 



Oil smell, pronounced 

 Slight oil show 

 Good oil show 

 Oil a gas show 

 Fresh water 

 Salt water 

 Flowing fresh water 

 Q] Flowing salt water 

 [3 Producing oil sand 

 OS Producing gas sand 



00 



+ 

 D 



column. Title blocks should include a short balanced title, the date, the 

 author's name, and a revision-date column. 



Some workers in compiling correlation information prefer to present 

 data in tabulated block form. This type of representation is permissible 

 when numerous formations are treated in regional studies. 



In recent years, many writers have reverted to isometric panel draw- 

 ings. This method of illustration introduces the third-dimensional con- 

 cept of stratigraphic relationships. Such drawings are of exceptional 

 value in that they are easily and readily interpreted (figs. 462, 463). 



