104-11 Investigating Exploratory Dry Holes as Fluid Migration Pathways Using Geophysical Logs in Kern County, California

Session: A Showcase of Undergraduate Research in Hydrogeology (Posters)

Presenting Author:

Authors:

Abstract:

Across California, more than 11,000 oil and gas wells, classified as “dry holes” due to their failure to yield commercially viable hydrocarbons, have been drilled outside the defined boundaries of oil and gas fields. Many of these wells were quickly abandoned, often without casing. In some instances, abandonment plugs were installed across critical intervals, such as the base of freshwater zones: however, large sections of open, uncased boreholes remain. These unsealed vertical pathways may facilitate the upward migration of fluids, creating potential hydraulic connections between deep saline zones and overlying, usable freshwater aquifers. The risk of this upward flow is heightened in areas experiencing declines in shallow groundwater levels due to intensive pumping, which alters local groundwater head gradients. 

Previous work has focused on collecting drilling, casing, and plug data for dry holes outside of oil and gas fields in Kern County (n=1,297) compared to the completed depths of water wells nearby. Those results showed that these wells often have long extents of open boreholes between plugged intervals. These open boreholes extend above the deepest perforation of nearby water wells, creating potential vertical fluid migration pathways.

To build upon the previous work focusing on well construction, we digitized spontaneous potential (sp) and resistivity tracks from publicly available geophysical logs, to investigate the lithology and groundwater salinity from wells included in the previous study to determine the potential for lateral fluid migration and connectivity between deep and shallow groundwater. Logs were plotted along cross sections throughout Kern County to illustrate the spatial relationship between groundwater, exploratory dry holes with open boreholes, and permeable sandss in the subsurface. Salinity (as total dissolved solids) was estimated for sands to better understand the groundwater quality along these cross sections.

Geological Society of America Abstracts with Program. Vol. 57, No. 6, 2025

doi: 10.1130/abs/2025AM-10908

© Copyright 2025 The Geological Society of America (GSA), all rights reserved.