California Oil, Gas, and Groundwater Program
Salinity within Geologic Formations Can Vary Considerably
Manager’s summary of Stephens and others, 2018
This study models subsurface salinity in the vicinity of Fruitvale and Rosedale Ranch oil fields.
Some key findings:
- Thickness and depth of fresh and brackish groundwater varies across these oil fields.
- Salinities vary within the Chanac formation from 5,000 to about 30,000 ppm TDS.
- This variation is systematic.
- Variation is caused by (1) clay layer thickness, (2) distance from a major freshwater recharge source, and (3) faults.