Geophysical well /Bore hole logging

Описание: Well logging, also known as borehole logging is the practice of making a detailed record (a well log) of the geologic formations penetrated by a borehole. The log may be based either on visual inspection of samples brought to the surface (geological logs) or on physical measurements made by instruments lowered into the hole (geophysical logs). Some types of geophysical well logs can be done during any phase of a well's history: drilling, completing, producing, or abandoning. Well logging is performed in boreholes drilled for the oil and gas, groundwater, mineral and geothermal exploration, as well as part of environmental and geotechnical studies.

Geophysical logging was carried out in cored boreholes in the Lac du Bonnet granitic batholith in southeastern Manitobs. The core was logged, and the holes were also logged by a downhole television system. Comparison of the lithological and television logs of the borehole with the geophysical logs shows that the latter have detected all significant fractures in the rock mass. Significant reductions in resistivity, as well as negative anomalies on the neutron logs, have been noted at these fractures zones. The sonic and density logs also indicate the fractures. The fluid resistivity logs appeared to indicate variations in groundwater salinity, and the focused-beam resistivity log reflected subtle changes in the lithology. Continuity of fractures was traced from borehole to borehole, using geophysical anomalies as markers.

#Geophysicalwall #Geology #Boreholedrilling