10 



Subsurface Geologic Methods 



1927 1928 1929 1930 1931 1933 1934 1935 I93S 1944 1945 1946 1947 1948 



16.2<»S 16,655 16,6 



17,823 17,696 



Figure 4. Drilling-depth records from 1927 to 1949. (Modified from World Oil.) 



services of a geologist who has the ability to coordinate and evaluate sub- 

 surface data. 



1927 Chansler-Canfield-Midway Oil Company's Olinda 96, Olinda, California. 



1928 Texon Oil and Land Company's University 1-B, Big Lake, west Texas. 



1929 Shell Oil Company's Nesa 1, Long Beach, California. 



1930 Standard Oil Company of California's Mascot 1, Midway, California. 



1931 Penn-Mex Fuel Company's Jardin 35, State of Vera Cruz, Mexico. 



1933 North Kettleman Oil & Gas Company's (later taken over by Union Oil Com- 

 pany) Lillis-Welch 1, Kettleman Hills, Kern County, California. 



1934 General Petroleum Corporation's Berry 1, Belridge, Kern County, California. 



1935 Gulf Oil Corporation's McElroy 103, Gulf-McElroy, Upton County, west Texas. 

 1938 Continental Oil Company's KCLA-2, Wasco, Kern County, California. 



1944 Standard Oil Company of California's KCL 20-13, South Coles Levee, Kern 

 County, California. 



1945 Phillips Petroleum Company's Schoeps 3, wildcat, Brazos County, Gulf Coast, 

 Texas. 



1946 Pacific Western Oil Corporation's National Royalties 1, Miramonte area, Kern 

 County, California. 



1947 Superior Oil Company of California's Weller 51-11, wildcat, Caddo County, 

 Oklahoma. 



1948 Standard Oil Company of California's Maxwell 1, Ventura County, California. 



1949 Superior Oil Company's Pacific Creek Unit 1, Sublette County, Wyoming. 



Comparative Use of Some Subsurface Techniques 



At present, lithologic- and electric-logging methods are most exten- 

 sively used in correlating the substrata. Radioactive and drill-time logging 

 are becoming increasingly important and will play a greater role in future 

 subsurface evaluations. Radioactive logging (gamma and neutron) has 

 proved its dependability in limestone and dolomite sections by its ability 

 to indicate porous strata which indirectly reflect possible petroliferous 

 zones. Controlled mechanical means of recording penetration rates have 

 greatly enhanced the value of the drill-time log and have placed data of 

 this category on a firm basis. 



Of the micropaleontologic criteria employed in correlating the sub- 



