Numerous other uses have been made of temperature records in both cased 

 and uncased holes. As gas enters a well, either through a hole in the casing or 

 into a bore hole on an uncased well, it expands and cools. This characteristic 

 has been used to find oiL-gas contacts or a hole in the casing. However, any use 

 of a temperature log presupposes that the temperature anomalies being measured 

 are of a greater magnitude than four of five degrees, these being the order of 

 formation thermal differences. 



Reprinted from Subsurface Geologic Methods, 1951, p. 439-449. 



355 



