Miscellaneous Subsurface Methods 



771 



The early results of soil-gas analysis obtained by the Russians indi- 

 cated a high value over the accumulation. American geochemists have ob- 

 served, except for a few minor exceptions, a ring or halo of high values 

 surrounding commercial production. 



Figure 409 shows the results of a survey in which a group of organic 

 constituents were removed from the soil samples by a highly selective sol- 



Figure 411. Geochemical well log of Godwin B-5 well, Friendswood field, 

 Harris County, Texas. (After Horvitz.) 



vent thought to have a unique origin in the surface as a result of subsurface 

 petroleum. The anomalous area has since been drilled with the discovery 

 of a Pennsylvanian reef trap. Seismograph and gravity work was also 

 done across the area, and the combined data was instrumental in the drill- 

 ing of the exploratory well. 



Figure 410 is the result of a survey in Jones County, Texas, in which 

 determinations were made of a group of trace-elements in the soil. Two 

 rather well-defined concentric halos were found in the distribution of the 

 diagnostic elements. This condition was predicted to be the result of mul- 



