California Oil, Gas, and Groundwater Program
Findings
![](https://webapps.usgs.gov/cogg/images/oil_field.jpg)
Jun 17, 2024
Spectral characterization of dissolved organic matter in groundwater to assess mixing with oil-field water near selected oil fields, southern California
Summary of Hansen and others (2023)
![](https://webapps.usgs.gov/cogg/images/net_injection.jpg)
Jun 17, 2024
Fluid Migration Pathways to Groundwater in Mature Oil Fields: Exploring the roles of water injection/production and oil-well integrity, Lost Hills and South Belridge Oil Fields
Summary of McMahon and others (2023).
![](https://webapps.usgs.gov/cogg/images/orcutt_fig1.jpg)
Mar 29, 2023
Occurrence of water and thermogenic gas from oil-bearing formations in groundwater near the Orcutt Oil Field, California, USA
Summary of Anders and others (2022)
![](https://webapps.usgs.gov/cogg/images/montebello_fig1.jpg)
Mar 29, 2023
Groundwater quality near the Montebello Oil Field, Los Angeles County, California
Summary of Stanton and others (2023)
![](https://webapps.usgs.gov/cogg/images/flowers_fig2.jpg)
Mar 28, 2023
Geologic controls on groundwater salinity reversal in North Coles Levee Oil Field, southern San Joaquin Valley, California, USA
Summary of Flowers and others (2022)
![](https://webapps.usgs.gov/cogg/images/poso4.png)
![](https://webapps.usgs.gov/cogg/images/noblegas.jpg)
Dec 30, 2021
Noble Gases Document Where Air has been Injected into the Subsurface
Summary of findings from Karolyte and others, 2021 and Tyne and others, 2021
![](https://webapps.usgs.gov/cogg/images/terry1.png)
Dec 7, 2021
3D Maps of Subsurface Salinity in the Montebello Oil Field, Los Angeles County
Summary of findings from Terry and others, 2021.
![](https://webapps.usgs.gov/cogg/images/relativerisk.jpg)
Sep 1, 2021
Patterns in the Risks to Groundwater Quality in the Vicinity of California Oil Fields
Summary of findings from McMahon and others, 2021
![](https://webapps.usgs.gov/cogg/images/shallow_salinity.png)
Dec 11, 2020
Shallow Groundwater Salinity in the Western San Joaquin Valley
Summary of findings from Ball and others, 2020
![](https://webapps.usgs.gov/cogg/images/es9b02395_0006.gif)
![](https://webapps.usgs.gov/cogg/images/kernmap.png)
Jan 14, 2020
Vertical Profile Data from Wells Document Oil-Field Waters Migrating From Surface Sump Ponds and Injection Sites
Summary of one set of findings from Gillespie and others, 2019
![](https://webapps.usgs.gov/cogg/images/Map-showing-location-and-relative-concentrations-of-methane-in-Los-Angeles-area-groundwater.png)
Oct 31, 2019
Methane in Los Angeles Area Groundwater from Microbial Sources
Manager’s summary of Kulongoski and others, 2018
![](https://webapps.usgs.gov/cogg/images/Fruitvale-and-Rosedale-Ranch-Modeled-Salinity-Cross-Section.png)
Oct 30, 2019
Salinity within Geologic Formations Can Vary Considerably
Manager’s summary of Stephens and others, 2018
![](https://webapps.usgs.gov/cogg/images/TDS-measured-weeks-after-hydraulic-fracturing.png)
![](https://webapps.usgs.gov/cogg/images/oil-field-waters-hydrogren-and-oxygen-isotopes-in-water-column.jpg)
Oct 28, 2019
Geochemical Patterns in Oil Field Fluids Vary Dramatically From Field to Field
Manager’s summary of McMahon and others (2018)
![](https://webapps.usgs.gov/cogg/images/Fraction-of-different-radium-isotopes-in-oil-field-waters.png)
Oct 27, 2019
224Radium Is the Predominant Radium Isotope in California Oil Field Waters
Key Finding in McMahon and others (2018).