One of the more common applications of geophysical logging for COLOG’s Arizona office is “The Water Well Suite”.
The WATER WELL suite
Consulting companies hired by water municipalities to drill and construct water supply wells will typically drill a pilot borehole and request a geophysical suite consisting of: Electric Resistivity and Natural Gamma Ray for identification of water-bearing sands versus clays, Full Waveform Sonic for P and S-wave evaluation for correlating lithology, 3-Arm Caliper or 4-Arm X-Y Caliper for borehole rugosity and Guard Resistivity for thin-bed resolution and lithology in poor water-quality environs. In complex lithologic environments the consulting company will additionally request Compensated Density and Compensated Neutron to assist with the lithologic characterization.
Typically the pilot borehole is subsequently reamed to a larger diameter and COLOG is asked to log a Ream Caliper and calculate borehole volume with depth to help the drillers with the final well construction. The last phase of this type of application is to come back after the well is constructed and conduct a Video Inspection Survey of the casing and screen downhole and perform a gyroscopic verticality survey to confirm the well casing is within deviation specifications.
