Michael J Stephens
Michael is a hydrogeologist in the California Water Science Center.
He works on the California Oil, Gas, and Groundwater program, where the goal is to answer questions about the impacts of oil and gas development on water resources in the state. He focuses on using geophysics, geochemistry, and geostatistics to map groundwater salinity in and around oil fields to indentify groundwater resources.
Science and Products
Groundwater elevation data and models in and around select California oil fields
This data release contains groundwater elevation data and the associated model/code used to create groundwater elevation surfaces in and around select oil fields in California. The data and model provided here are intended to supplement interpretative manuscripts. Specific study areas will be added as Child Items found in this data release. Groundwater elevations are usually collected from individ
Idle well fluid measurements for oil and gas wells in California
This dataset consists of 119,494 lines of data consisting of idle well fluid level depth, auxiliary measurements, and well parameters from California oil and gas wells that were reported to the California Department of Conservation, Geologic Energy Management Division (CalGEM). The dataset was provided by CalGEM in March 2018 and includes measurements made from 1976 to 2018. There are 5 sets of op
Geological, geochemical, and geophysical data from the Lost Hills and Belridge oil fields
The U.S. Geological Survey (USGS) in cooperation with the California State Water Resources Control Board compiled and analyzed data for mapping groundwater salinity and characterizing aquifer systems in and near selected oil and gas fields in California. Data for the Lost Hills, North Belridge, and South Belridge oil fields include production and injection volumes, oil show data, formation pressur
Geophysical and geological data for select petroleum wells in North Coles Levee Oil Field, Kern County, California
This dataset includes geological and geophysical data from petroleum wells located in the North Coles Levee Oil Field, Kern County, California. The purpose of this dataset is to describe groundwater salinity trends and the related geological controls. These data are used in an interpretive manuscript that characterizes a salinity inversion (lower-salinities found below higher-salinities) in North
Geophysical, geological, hydrological, and geochemical data for aquifer salinity mapping in the Elk Hills, Buena Vista, and Coles Levee Oil Fields, Kern County, California
The U.S. Geological Survey (USGS) in cooperation with the California State Water Resources Control Board (State Water Board) compiled and analyzed data for mapping groundwater salinity, characterizing aquifer systems, and documenting the effects of oil field water injection in the Elk Hills Elk Hills, Buena Vista, and Coles Levee Oil Fields, San Joaquin Valley, California. Data provided in this da
Geochemical, geological, and geophysical data for wells in the Poso Creek oil and gas field, Kern County, California
The U.S. Geological Survey (USGS) in cooperation with the California State Water Resources Control Board and the U.S. Bureau of Land Management compiled and analyzed data for mapping groundwater salinity and characterizing aquifer systems in and around selected oil and gas fields in California. Data were collected for the Poso Creek oil field area which includes well construction data, production
Mud logs from the Oxnard Oil Field, Ventura County, California
The U.S. Geological Survey (USGS) in cooperation with the California State Water Resources Control Board (SWRCB) compiled and digitized mud logs from oil and gas wells in the Oxnard Oil Field area. Scanned copies of the mud logs were downloaded from the California Geologic Energy Management Division (CalGEM) online data and were digitized. Thirteen available mud logs associated with the Pliocene T
Fluid levels in the Oxnard Oil Field, Ventura County, California
The U.S. Geological Survey (USGS), in cooperation with the California State Water Resources Control Board (SWRCB), compiled Fall 2017 fluid level elevation data from idle oil and gas wells in the Oxnard Oil Field to estimate vertical hydraulic head difference between oil production and overlying groundwater aquifer zones. Fluid elevations came from two sources, measurements in idle oil and gas wel
Geophysical and geochemical data for salinity mapping in the Midway-Sunset oil field area
The U.S. Geological Survey (USGS) and California State University-Sacramento, in cooperation with the California State Water Resources Control Board and U.S. Bureau of Land Management, compiled and analyzed data for mapping groundwater salinity in selected oil and gas fields in California. The data for the Midway-Sunset (MWSS) oil field includes digitized borehole geophysical data, geochemical ana
Geochemical and geophysical data for wells in the Fruitvale and Rosedale Ranch oil and gas fields, Kern County, California, USA
The U.S. Geological Survey (USGS) in cooperation with the California State Water Resources Control Board compiled and analyzed data for the purpose of mapping groundwater salinity in selected oil and gas fields in California. The data for the Fruitvale and Rosedale Ranch oil fields include well construction data, digitized borehole geophysical data, geochemical analyses of water samples from oil a
Multiple-well monitoring site within the Poso Creek Oil Field, Kern County, California
IntroductionThe Poso Creek Oil Field is one of the many fields selected for regional groundwater mapping and monitoring by the California State Water Resources Control Board as part of the Oil and Gas Regional Monitoring Program (RMP; California State Water Resources Control Board, 2015, 2022b; U.S. Geological Survey, 2022a). The U.S. Geological Survey (USGS), in cooperation with the California St
Authors
Rhett R. Everett, Peter B. McMahon, Michael J. Stephens, Janice M. Gillespie, Mackenzie M. Shepherd, Nicole C. Fenton
Geologic controls on groundwater salinity reversal in North Coles Levee Oil Field, southern San Joaquin Valley, California, USA
This paper documents a reversal in the groundwater salinity depth gradient in the North Coles Levee Oil Field in the San Joaquin Valley, California. Salinity, measured in mg/L, was mapped with water quality data from groundwater and oil and gas wells and salinity estimated from oil and gas well borehole geophysical logs using Archie's equation. The resulting three-dimensional salinity volume shows
Authors
Michael D Flowers, David H. Shimabukuro, Michael J. Stephens, John G. Warden, Janice M. Gillespie, Will Chang
Airborne electromagnetic survey results near the Poso Creek oil field, San Joaquin Valley, California, fall 2016
An airborne electromagnetic survey west of the Poso Creek oil field, located in the southeastern San Joaquin Valley, California, was flown in October 2016 to improve understanding of the hydrogeologic setting and the distribution of groundwater salinity in the area. The airborne electromagnetic data were used to develop resistivity models of the subsurface, where the mean depth of investigation is
Authors
Katrina D. Zamudio, Lyndsay B. Ball, Michael J. Stephens
Mapping aquifer salinity gradients and effects of oil field produced water disposal using geophysical logs: Elk Hills, Buena Vista and Coles Levee Oil Fields, San Joaquin Valley, California
The effects of oil and gas production on adjacent groundwater quality are becoming a concern in many areas of the United States. As a result, it has become increasingly important to identify which aquifers require monitoring and protection. In this study, we map the extent of groundwater with less than 10,000 mg/L TDS both laterally and vertically near the Elk Hills, Buena Vista and Coles Levee Oi
Authors
Janice M. Gillespie, Michael J. Stephens, Will Chang, John G. Warden
Stratigraphic and structural controls on groundwater salinity variations in the Poso Creek Oil Field, Kern County, California, USA
Groundwater total dissolved solids (TDS) distribution was mapped with a three-dimensional (3D) model, and it was found that TDS variability is largely controlled by stratigraphy and geologic structure. General TDS patterns in the San Joaquin Valley of California (USA) are attributed to predominantly connate water composition and large-scale recharge from the adjacent Sierra Nevada. However, in sma
Authors
Michael J. Stephens, David H. Shimabukuro, Will Chang, Janice M. Gillespie, Zack Levinson
Groundwater quality of aquifers overlying the Oxnard Oil Field, Ventura County, California
Groundwater samples collected from irrigation, monitoring, and municipal supply wells near the Oxnard Oil Field were analyzed for chemical and isotopic tracers to evaluate if thermogenic gas or water from hydrocarbon-bearing formations have mixed with surrounding groundwater. New and historical data show no evidence of water from hydrocarbon-bearing formations in groundwater overlying the field. H
Authors
Celia Z. Rosecrans, Matthew K. Landon, Katherine Marie Ransom, Janice M. Gillespie, Justin T. Kulongoski, Michael J. Stephens, Andrew G. Hunt, David H. Shimabukuro, Tracy Davis
A novel method for the extraction, purification and characterization of noble gases in produced fluids
Hydrocarbon systems with declining or viscous oil production are often stimulated using enhanced oil recovery (EOR) techniques, such as the injection of water, steam and CO2, in order to increase oil and gas production. As EOR and other methods of enhancing production such as hydraulic fracturing have become more prevalent, environmental concerns about the impact of both new and historical hydroca
Authors
Rebecca L. Tyne, Peter H Barry, D J Hillegonds, Andrew Hunt, Justin T. Kulongoski, Michael J. Stephens, D.J. Byrne, C. J. Ballentine
Groundwater salinity and the effects of produced water disposal in the Lost Hills-Belridge oilfields, Kern County, California
Increased oil and gas production in many areas has led to concerns over the effects these activities may be having on nearby groundwater quality. In this study we determine the lateral and vertical extent of groundwater with less than 10,000 milligrams per liter (mg/l) total dissolved solids (TDS) near the Lost Hills-Belridge oilfields in northwestern Kern County, California and document evidence
Authors
Janice M. Gillespie, Tracy Davis, Michael J. Stephens, Lyndsay B. Ball, Matthew K. Landon
Groundwater salinity mapping using geophysical log analysis within the Fruitvale and Rosedale Ranch oil fields, Kern County, California, USA
A method is presented for deriving a volume model of groundwater total dissolved solids (TDS) from borehole geophysical and aqueous geochemical measurements. While previous TDS mapping techniques have proved useful in the hydrogeologic setting in which they were developed, they may yield poor results in settings with lithological heterogeneity, complex water chemistry, or limited data. Problems ar
Authors
Michael J. Stephens, David H. Shimabukuro, Janice M. Gillespie, Will Chang
Tracing enhanced oil recovery signatures in casing gases from the Lost Hills oil field using noble gases
Enhanced oil recovery (EOR) and hydraulic fracturing practices are commonly used methods to improve hydrocarbon extraction efficiency; however the environmental impacts of such practices remain poorly understood. EOR is particularly prevalent in oil fields throughout California where water resources are in high demand and disposal of high volumes of produced water may affect groundwater quality. C
Authors
Peter H. Barry, Justin T. Kulongoski, Matthew K. Landon, R. L. Tyne, Janice M. Gillespie, Michael J. Stephens, D.J. Hillegonds, D.J. Byrne, C.J. Ballentine
Science and Products
- Data
Groundwater elevation data and models in and around select California oil fields
This data release contains groundwater elevation data and the associated model/code used to create groundwater elevation surfaces in and around select oil fields in California. The data and model provided here are intended to supplement interpretative manuscripts. Specific study areas will be added as Child Items found in this data release. Groundwater elevations are usually collected from individIdle well fluid measurements for oil and gas wells in California
This dataset consists of 119,494 lines of data consisting of idle well fluid level depth, auxiliary measurements, and well parameters from California oil and gas wells that were reported to the California Department of Conservation, Geologic Energy Management Division (CalGEM). The dataset was provided by CalGEM in March 2018 and includes measurements made from 1976 to 2018. There are 5 sets of opGeological, geochemical, and geophysical data from the Lost Hills and Belridge oil fields
The U.S. Geological Survey (USGS) in cooperation with the California State Water Resources Control Board compiled and analyzed data for mapping groundwater salinity and characterizing aquifer systems in and near selected oil and gas fields in California. Data for the Lost Hills, North Belridge, and South Belridge oil fields include production and injection volumes, oil show data, formation pressurGeophysical and geological data for select petroleum wells in North Coles Levee Oil Field, Kern County, California
This dataset includes geological and geophysical data from petroleum wells located in the North Coles Levee Oil Field, Kern County, California. The purpose of this dataset is to describe groundwater salinity trends and the related geological controls. These data are used in an interpretive manuscript that characterizes a salinity inversion (lower-salinities found below higher-salinities) in NorthGeophysical, geological, hydrological, and geochemical data for aquifer salinity mapping in the Elk Hills, Buena Vista, and Coles Levee Oil Fields, Kern County, California
The U.S. Geological Survey (USGS) in cooperation with the California State Water Resources Control Board (State Water Board) compiled and analyzed data for mapping groundwater salinity, characterizing aquifer systems, and documenting the effects of oil field water injection in the Elk Hills Elk Hills, Buena Vista, and Coles Levee Oil Fields, San Joaquin Valley, California. Data provided in this daGeochemical, geological, and geophysical data for wells in the Poso Creek oil and gas field, Kern County, California
The U.S. Geological Survey (USGS) in cooperation with the California State Water Resources Control Board and the U.S. Bureau of Land Management compiled and analyzed data for mapping groundwater salinity and characterizing aquifer systems in and around selected oil and gas fields in California. Data were collected for the Poso Creek oil field area which includes well construction data, productionMud logs from the Oxnard Oil Field, Ventura County, California
The U.S. Geological Survey (USGS) in cooperation with the California State Water Resources Control Board (SWRCB) compiled and digitized mud logs from oil and gas wells in the Oxnard Oil Field area. Scanned copies of the mud logs were downloaded from the California Geologic Energy Management Division (CalGEM) online data and were digitized. Thirteen available mud logs associated with the Pliocene TFluid levels in the Oxnard Oil Field, Ventura County, California
The U.S. Geological Survey (USGS), in cooperation with the California State Water Resources Control Board (SWRCB), compiled Fall 2017 fluid level elevation data from idle oil and gas wells in the Oxnard Oil Field to estimate vertical hydraulic head difference between oil production and overlying groundwater aquifer zones. Fluid elevations came from two sources, measurements in idle oil and gas welGeophysical and geochemical data for salinity mapping in the Midway-Sunset oil field area
The U.S. Geological Survey (USGS) and California State University-Sacramento, in cooperation with the California State Water Resources Control Board and U.S. Bureau of Land Management, compiled and analyzed data for mapping groundwater salinity in selected oil and gas fields in California. The data for the Midway-Sunset (MWSS) oil field includes digitized borehole geophysical data, geochemical anaGeochemical and geophysical data for wells in the Fruitvale and Rosedale Ranch oil and gas fields, Kern County, California, USA
The U.S. Geological Survey (USGS) in cooperation with the California State Water Resources Control Board compiled and analyzed data for the purpose of mapping groundwater salinity in selected oil and gas fields in California. The data for the Fruitvale and Rosedale Ranch oil fields include well construction data, digitized borehole geophysical data, geochemical analyses of water samples from oil a - Publications
Multiple-well monitoring site within the Poso Creek Oil Field, Kern County, California
IntroductionThe Poso Creek Oil Field is one of the many fields selected for regional groundwater mapping and monitoring by the California State Water Resources Control Board as part of the Oil and Gas Regional Monitoring Program (RMP; California State Water Resources Control Board, 2015, 2022b; U.S. Geological Survey, 2022a). The U.S. Geological Survey (USGS), in cooperation with the California StAuthorsRhett R. Everett, Peter B. McMahon, Michael J. Stephens, Janice M. Gillespie, Mackenzie M. Shepherd, Nicole C. FentonGeologic controls on groundwater salinity reversal in North Coles Levee Oil Field, southern San Joaquin Valley, California, USA
This paper documents a reversal in the groundwater salinity depth gradient in the North Coles Levee Oil Field in the San Joaquin Valley, California. Salinity, measured in mg/L, was mapped with water quality data from groundwater and oil and gas wells and salinity estimated from oil and gas well borehole geophysical logs using Archie's equation. The resulting three-dimensional salinity volume showsAuthorsMichael D Flowers, David H. Shimabukuro, Michael J. Stephens, John G. Warden, Janice M. Gillespie, Will ChangAirborne electromagnetic survey results near the Poso Creek oil field, San Joaquin Valley, California, fall 2016
An airborne electromagnetic survey west of the Poso Creek oil field, located in the southeastern San Joaquin Valley, California, was flown in October 2016 to improve understanding of the hydrogeologic setting and the distribution of groundwater salinity in the area. The airborne electromagnetic data were used to develop resistivity models of the subsurface, where the mean depth of investigation isAuthorsKatrina D. Zamudio, Lyndsay B. Ball, Michael J. StephensMapping aquifer salinity gradients and effects of oil field produced water disposal using geophysical logs: Elk Hills, Buena Vista and Coles Levee Oil Fields, San Joaquin Valley, California
The effects of oil and gas production on adjacent groundwater quality are becoming a concern in many areas of the United States. As a result, it has become increasingly important to identify which aquifers require monitoring and protection. In this study, we map the extent of groundwater with less than 10,000 mg/L TDS both laterally and vertically near the Elk Hills, Buena Vista and Coles Levee OiAuthorsJanice M. Gillespie, Michael J. Stephens, Will Chang, John G. WardenStratigraphic and structural controls on groundwater salinity variations in the Poso Creek Oil Field, Kern County, California, USA
Groundwater total dissolved solids (TDS) distribution was mapped with a three-dimensional (3D) model, and it was found that TDS variability is largely controlled by stratigraphy and geologic structure. General TDS patterns in the San Joaquin Valley of California (USA) are attributed to predominantly connate water composition and large-scale recharge from the adjacent Sierra Nevada. However, in smaAuthorsMichael J. Stephens, David H. Shimabukuro, Will Chang, Janice M. Gillespie, Zack LevinsonGroundwater quality of aquifers overlying the Oxnard Oil Field, Ventura County, California
Groundwater samples collected from irrigation, monitoring, and municipal supply wells near the Oxnard Oil Field were analyzed for chemical and isotopic tracers to evaluate if thermogenic gas or water from hydrocarbon-bearing formations have mixed with surrounding groundwater. New and historical data show no evidence of water from hydrocarbon-bearing formations in groundwater overlying the field. HAuthorsCelia Z. Rosecrans, Matthew K. Landon, Katherine Marie Ransom, Janice M. Gillespie, Justin T. Kulongoski, Michael J. Stephens, Andrew G. Hunt, David H. Shimabukuro, Tracy DavisA novel method for the extraction, purification and characterization of noble gases in produced fluids
Hydrocarbon systems with declining or viscous oil production are often stimulated using enhanced oil recovery (EOR) techniques, such as the injection of water, steam and CO2, in order to increase oil and gas production. As EOR and other methods of enhancing production such as hydraulic fracturing have become more prevalent, environmental concerns about the impact of both new and historical hydrocaAuthorsRebecca L. Tyne, Peter H Barry, D J Hillegonds, Andrew Hunt, Justin T. Kulongoski, Michael J. Stephens, D.J. Byrne, C. J. BallentineGroundwater salinity and the effects of produced water disposal in the Lost Hills-Belridge oilfields, Kern County, California
Increased oil and gas production in many areas has led to concerns over the effects these activities may be having on nearby groundwater quality. In this study we determine the lateral and vertical extent of groundwater with less than 10,000 milligrams per liter (mg/l) total dissolved solids (TDS) near the Lost Hills-Belridge oilfields in northwestern Kern County, California and document evidenceAuthorsJanice M. Gillespie, Tracy Davis, Michael J. Stephens, Lyndsay B. Ball, Matthew K. LandonGroundwater salinity mapping using geophysical log analysis within the Fruitvale and Rosedale Ranch oil fields, Kern County, California, USA
A method is presented for deriving a volume model of groundwater total dissolved solids (TDS) from borehole geophysical and aqueous geochemical measurements. While previous TDS mapping techniques have proved useful in the hydrogeologic setting in which they were developed, they may yield poor results in settings with lithological heterogeneity, complex water chemistry, or limited data. Problems arAuthorsMichael J. Stephens, David H. Shimabukuro, Janice M. Gillespie, Will ChangTracing enhanced oil recovery signatures in casing gases from the Lost Hills oil field using noble gases
Enhanced oil recovery (EOR) and hydraulic fracturing practices are commonly used methods to improve hydrocarbon extraction efficiency; however the environmental impacts of such practices remain poorly understood. EOR is particularly prevalent in oil fields throughout California where water resources are in high demand and disposal of high volumes of produced water may affect groundwater quality. CAuthorsPeter H. Barry, Justin T. Kulongoski, Matthew K. Landon, R. L. Tyne, Janice M. Gillespie, Michael J. Stephens, D.J. Hillegonds, D.J. Byrne, C.J. Ballentine