BASE GEOPHYSICS

There are many different geophysical investigation techniques, However when there is a need in exploring detailed information about the subsurface, we have to drill the hole and make a detailed collection of subsurface data, this is termed Borehole geophysics . This procedure involves the depth wise sequential record of physical parameters such as resistivity , density, temperature. It is sometimes known as Geophysical Logging or Geophysical well logging. There are many different geophysical logging however this post will let you know about electrical logging which is commonly includes the resistivity log and self-potential (SP) log . geologic log vs geophysical log G eological Log: This displays variation of subsurface geology ( lithology/rock types ) with depth. Such as from dry sand (top) to sand (middle) to clay (bottom). Geophysical Log: This displays variation of subsurface physical parameters with depth. The term well log is more general that includes both geological and ge...

Most surface geophysical techniques provide vast information about subsurfaces. However when it comes to trace detailed information about subsurface in a certain cross section- area, it is highly recommended to deploy these techniques in a drilled hole. This is termed as Borehole geophysics .  What is Borehole Geophysics? Borehole geophysics involves the depth wise sequential record of physical parameters such as resistivity, density, temperature, porosity, etc. It may sometimes be known as Geophysical Logging . Borehole : Is the narrow hole drilled into ground for the purpose either of obtaining subsurface information or extracting fluids such as water, gas, oil, contaminants. It is the same as a well, but they may differ due to the fact that the borehole is drilled at great depth and has small diameter compared to traditional wells. The basic geophysical borehole system is made up of these parts,  Downhole probe : It consists of sensing instruments/equipment that are lower...

There are many different geophysical investigation techniques, However when it comes to exploring detailed information about the subsurface, we need to drill the hole and make a detailed collection of subsurface data related to physical properties of the subsurface materials, this is termed as Borehole or downhole geophysics . Borehole geophysics involves the depth wise sequential record of physical parameters such as resistivity, density, temperature. It may sometimes be known as Geophysical logging . There are many different geophysical logging techniques however this post is going to describe briefly about electrical borehole logging . Electrical Borehole logging What is electrical borehole logging? Electrical borehole logging measures the flow of electric current in and adjacent to a well, using the same principles as various surface electrical methods. Types of Electrical Borehole Logging 1. resistivity logging 1.1 Single-Point Resistance logging This measures the resistance in o...