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Groundwater Quality Near the Placerita Oil Field, California, 2018

Scientific Investigations Report 2024-5042
Prepared in cooperation with the California State Water Resources Control Board
By: , , , , , , , , and 
https://doi.org/10.3133/sir20245042

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Abstract

Groundwater-quality data and potential fluid-migration pathways near the Placerita Oil Field in Los Angeles County, California, were examined by the U.S. Geological Survey to determine if oil-field fluids (water and gas from oil-producing and non-producing zones) have mixed with groundwater resources. Six of the 13 new groundwater samples collected for this study contained petroleum hydrocarbons, thermogenic gas, inorganic chemical signatures, and (or) isotopic values consistent with potential mixing with fluids from hydrocarbon-bearing formations.

For historical groundwater samples, benzene was the most detected petroleum hydrocarbon. The historical groundwater samples with a benzene concentration greater than 0.5 micrograms per liter were from environmental monitoring wells at industrial or commercial facilities unrelated to oil and gas development that, in many cases, have identified soil or groundwater contamination and were not typically analyzed for other constituents that could provide additional lines of evidence for potential mixing with oil-field fluids. Methane was not detected in any of the 12 historical samples with a reported measurement.

Reviewing historical data revealed factors that could potentially adversely affect groundwater quality in the study area. These factors include modified hydraulic gradients caused by large volumes of water extracted from the main production area and reinjected downgradient into nonproducing zones, well-barrier failures in wells constructed in the northern part of the oil field before the 1970s, well-barrier failures in produced-water disposal wells downgradient from the main production area, and naturally occurring hydrocarbons at shallow intervals. The groundwater samples most geochemically similar to samples from hydrocarbon-bearing formations were in areas where hydrocarbons are naturally occurring at shallow intervals and where oil development is at shallow depths. Additional data for hydraulic heads, water quality, and formation temperatures at multiple depths in areas with large injection volumes and well-integrity issues are needed to evaluate whether those factors have contributed to mixing between fluids from oil-producing or injection formations and groundwater resources.

Suggested Citation

Stanton, J.S., Landon, M.K., Shimabukuro, D.H., Kulongoski, J.T., Hunt, A.G., McMahon, P.B., Cozzarelli, I.M., Anders, R., and Sowers, T.A., 2024, Groundwater quality near the Placerita Oil Field, California, 2018: U.S. Geological Survey Scientific Investigations Report 2024–5042, 65 p., https://doi.org/10.3133/sir20245042.

ISSN: 2328-0328 (online)

Study Area

Table of Contents

  • Acknowledgments
  • Abstract
  • Introduction
  • Groundwater Quality
  • Potential Fluid-Migration Pathways
  • Relation of Groundwater Quality to Pathways
  • Study Limitations
  • Summary
  • References Cited
  • Appendix 1. Glossary
  • Appendix 2. Supplemental Tables for the Placerita Oil Field Study Area, California, 2018
  • Appendix 3. Quality of Groundwater Samples Collected for the Placerita Oil Field Study Area, California, 2018
  • Appendix 4. Noble Gas Compositions of Groundwater and Produced Water in the Placerita Oil Field Study Area, California, 2018
Publication type Report
Publication Subtype USGS Numbered Series
Title Groundwater quality near the Placerita Oil Field, California, 2018
Series title Scientific Investigations Report
Series number 2024-5042
DOI 10.3133/sir20245042
Year Published 2024
Language English
Publisher U.S. Geological Survey
Publisher location Reston, VA
Contributing office(s) California Water Science Center
Description Report: ix, 65 p.; 2 Data Releases; 7 Tables
Country United States
State California
Other Geospatial Placerita Oil Field
Online Only (Y/N) Y
Additional Online Files (Y/N) Y
Google Analytic Metrics Metrics page
Additional publication details