Design/Installation of Deep Groundwater Monitoring Wells in an Arid Region
WHITE, ALAN E., Uribe & Associates, Bakersfield, CA
Oil field drilling and completion techniques were successfully applied to the installation of deep piezometer/monitoring wells in an arid region of California. Previously, standard water well installation and completion techniques had not been effective in this area.
Three boreholes were continuously cored to depths of approximately 1000 ft. Two methods of coring were used, wireline retrieval and conventional coring. Core recovery was difficult because most of the sediments were poorly consolidated, and the unsaturated zone extended to over 650 ft.
Clean completion techniques enabled successful sampling in a low-yield water formation. These techniques included cementing casing at the top of the desired sampling interval, under-reaming the completion interval, and installing a screen and gravel pack using water-circulating tools. This system provided an advantage over tremie pipe techniques normally used to install gravel and to seal protective casings in monitoring wells.
AAPG Search and Discovery Article #91009©1991 AAPG-SEPM-SEG-SPWLA Pacific Section Annual Meeting, Bakersfield, California, March 6-8, 1991 (2009)