255] F. Reeves 57 



ORIGIN OF THE NATURAL BRINES OF OIL FIELDS 



By FRANK BEEVES 



The origin of the concentrated brines so universally found 

 in oil-bearing strata and other porous, unmetamorphosed 

 rocks lying at depths below the zone of active circulating 

 ground water has never been definitely established. By some 

 these waters are thought to be of meteoric or surface origin, 

 t. e., they are rain waters which have in passing downward 

 through the strata dissolved out of the rock material the salts 

 which they now hold in solution. Others consider them to be 

 the sea water which has remained in the pores of the strata 

 ever since their deposition. 



A study of the occurrence and chemical nature of the brines 

 found in the oil sands of southwestern Pennsylvania and West 

 Virginia furnishes data which indicate that the waters in this 

 area are connate or of ocean origin. This conclusion is based 

 on the following lines of evidence : 



(1) The distribution of the water suggests that it is not of 

 meteoric origin. 



(2) There are no adequate explanations of how the water 

 of deposition has been removed from the strata. 



(3) The association of the dry sands and "red beds 5 ' of 

 the area indicate that the water present accumulated with the 

 sediments as they were being deposited. 



(4) The chemical nature of the brine points to it being of 

 connate origin. 



THE DISTRIBUTION" OF WATER 



In order to consider this phase of the evidence it will be 

 necessary to describe briefly the structural and stratigraphic 

 features of the area under discussion. 



Structure of the Area. The brines occur in the Car- 

 boniferous and Devonian strata of the Appalachian coal basin. 



