Geophysical Well Logging in Order to Reduce Operating Costs in Mineral Exploration

Abstract

The geophysical well logging is the practice of making a detailed record of the geological formations penetrated by a well. The record can be based on visual inspection of samples brought to the surface (geological records) or physical measurements made by instruments lowered into the hole (geophysical records). Some types of logs can be made during any phase of a well's history: drilling, completion, production, or abandonment. The logs are carried out in drilled holes for the exploration of oil and gas, underground, mineral, and geothermal water, in addition to part of environmental and geotechnical studies. In the case of mineral exploration, the main interest in using well logs is to seek on compositional and textural variations caused by changes in moisture and hardness of the rocks. Thus, the technic is satisfactory to detect the presence of clay and hydrated bodies, as well as the transition between friable and compact minerals. Therefore, the results open possibilities to changes exploratory drilling meshes with partial replacement of core sampling by rotary percussive boreholes. This allows to do a mineral exploration with lower costs using a faster and cheaper technique, but always using well logs to support the geological interpretation in subsurface.