Mud logs from the Oxnard Oil Field, Ventura County, California

Dates

Publication Date: 2021-01-28
Start Date: 2007-08-04
End Date: 2013-09-05

Citation

Stephens, M.J., Sowers, T.A., Courser, H.N., Bunch, J.D., and Rosecrans, C.Z., 2021, Mud logs from the Oxnard Oil Field, Ventura County, California: U.S. Geological Survey data release, https://doi.org/10.5066/P913QDD5.

Summary

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 Tar Sand pool code (Vaca Tar Sand) were digitized. Mud-logging technology (mud logs) allows for identification and relative concentration measurement in parts per million by volume (ppmv) of light hydrocarbon gases (methane through pentane) occurring in drilling mud returned to the surface throughout the drilling process as well as estimates [...]

Summary

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 Tar Sand pool code (Vaca Tar Sand) were digitized. Mud-logging technology (mud logs) allows for identification and relative concentration measurement in parts per million by volume (ppmv) of light hydrocarbon gases (methane through pentane) occurring in drilling mud returned to the surface throughout the drilling process as well as estimates of percent oil in mud log cuttings (oil shows). The data provided here are apparent concentrations of hydrocarbon gas (methane, ethane, propane, butane, and pentane) and percent oil shows with depth. Apparent concentrations do not equal actual concentrations or presence of the compound at a given depth. Apparent concentrations reflect a digitized position on a mud log and positive values may not indicate presence of the compound; these values are reported as “mud log RAW.csv” values in this data release (see process step 1 and 2 for further description). Estimates of apparent concentration compared to other depths should be estimated by calculating the deviation with depth from the baseline or minimum value. In the larger work, the reported apparent concentrations represent a relative apparent concentration calculated from the raw digitized data for each mud log and each respective gas component (methane, ethane, propane, butane, and pentane); these value are reported as “mud log PROCESSED.csv” (see process step 3 for further description). A baseline concentration was estimated for each processed mud log and represents the minimum apparent relative gas concentration considered for evaluating the presence of the gas components (see process step 4 for further details). Values above baseline or minimum at a single discrete depth should be regarded with caution. Apparent concentration values should not be compared between sites, as minimum or baseline values result from differences in the digitizing process between sites. These data were analyzed in an accompanying manuscript as part of the SWRCB oil and gas Regional Monitoring Program and the USGS California Oil, Gas, and Groundwater (COGG) program to assess regional groundwater quality overlying and adjacent to the Oxnard Oil Field.

Contacts

Point of Contact :: Matthew K Landon
Originator :: Michael J Stephens, Theron A Sowers, Haley N Courser, Justin D Bunch, Celia Z Rosecrans
Metadata Contact :: Michael J Stephens
Publisher :: U.S. Geological Survey
Distributor :: U.S. Geological Survey - ScienceBase
SDC Data Owner :: California Water Science Center
USGS Mission Area :: Water Resources

Attached Files

Click on title to download individual files attached to this item.

Baseline concentrations.csv “Baseline concentrations”		187 Bytes	text/csv
mud-logs-LAS-RAW.zip “Oxnard mud logs LAS RAW”		823.28 KB	application/zip
mud-logs-CSV-RAW.zip “Oxnard mud logs CSV RAW”		711.04 KB	application/zip
mud-logs-CSV-PROCESSED.zip “Oxnard mud logs CSV PROCESSED”		826.75 KB	application/zip
Oxnard mud logs data release metadata.xml “Oxnard mud logs metadata” Original FGDC Metadata	View	35.14 KB	application/fgdc+xml

Related External Resources

Type: Related Primary Publication

Rosecrans, C.Z., Landon, M.K., McMahon, P.B., Gillespie, J.M., Kulongoski, J.T., Stephens, M.J., Hunt, A.G., Shimabukuro, D.H., and Davis, T.A., 2021, Groundwater quality of aquifers overlying the Oxnard Oil Field, Ventura County, California: Science of the Total Environment. https://doi.org/10.1016/j.scitotenv.2020.144822	https://doi.org/10.1016/j.scitotenv.2020.144822

Type: Related Data Release

Metzger, L.F., and Herrera, P.J., 2020, Historical produced water chemistry data compiled for the Orcutt and Oxnard oil fields, Santa Barbara and Ventura Counties, southern California: U.S. Geological Survey data release. https://doi.org/10.5066/P9AYRXBD	https://doi.org/10.5066/P9AYRXBD
Rosecrans, C.Z., Rodriguez, O., Davis, T.A., Teunis, J.A., Johnson, J., McCarlson, A., and Qi, S.L., 2021, Water chemistry data for samples collected at groundwater sites near the Oxnard oil field, June 2017–August 2018, Ventura County, California: U.S. Geologic Survey data release. https://doi.org/10.5066/P99EHQ8H	https://doi.org/10.5066/P99EHQ8H
Stephens, M.J., Shimabukuro, D.H., Rosecrans, C.Z., and Watson, E., 2021, Fluid levels in the Oxnard Oil Field, Ventura County, California: U.S. Geological Survey data release. https://doi.org/10.5066/P9UG4BP3	https://doi.org/10.5066/P9UG4BP3

Type: Citation

Crain, E.R., 2010, Crain’s Petrophysical Handbook, Mud Logging and Mud Gas Logging webpage version, accessed September 29, 2019. https://www.spec2000.net/08-mud.htm	https://www.spec2000.net/08-mud.htm
Crangle, R.D., Jr., 2007, Log ASCII Standard (LAS) files for geophysical wire line well logs and their application to geologic cross sections through the central Appalachian basin: U.S. Geological Survey Open File Report 2007-1142, 14 p. https://pubs.usgs.gov/of/2007/1142/	https://pubs.usgs.gov/of/2007/1142/
Swanson, R.G., 1981, Sample Examination Manual: American Association of Petroleum Geologists, 54 p. https://doi.org/10.1306/Mth1413	https://doi.org/10.1306/Mth1413

Purpose

The purpose of this data release is to provide the digitized mud log data that were compiled to be used in analyzing regional groundwater quality in areas of oil and gas production activity in the Oxnard Oil Field.

Mud logs from the Oxnard Oil Field, Ventura County, California

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