Well logging is performed in oil and gas exploration wells to obtain the physical characteristics of underground formations. Thereafter. these wells are cased. Through-casing logging is important in mature fields and for wells that are cased without logging due to borehole stability issues. https://www.roneverhart.com/Seagate-Exos-7E2-ST1000NM0008-1TB-7-2K-RPM-SATA-6Gb-s-512n-128MB-3-5-Hard-Drive/