CORRELATION OF ISOGEOTHERMAL SURFACES 41 
an important factor. As shown in Fig. 4, the isothermal surfaces are excep- 
tionally smooth and uniform and follow the top of the upper oil producing 

Q 8 A) [s) 
bs) Q 9 
8 Q 9 S x S 
~ + es a r) ¢ 
DEPTH-FEET 
Fig. 6. Depth-temperatme curve, deep well No. 2, Tucker and 
Johnson lease, Long Beach, California. 
strata, the Lower Brown Zone, with marvelous precision. That uniformity in 
these surfaces was to be expected is suggested by the depth-temperature. 
I/O deg. Fobr| 
A, 
a aa Be 
ae 
oe 
a0 Peg-fehe)  40f 
at 

Fig. 7. Longitudinal section of Long Beach oil field. (See 4, first reference.) 
curve of deep well No. 2, Fig. 6. This curve like many others in the Long 
Beach field, shows a slight rise in temperature at a depth of about 1000 feet, 
185 
