Today I followed a fellow petroleum engineer commencing open hole logging using Schlumberger’s supercombo tool. It’s basically a combination of gamma ray tool for sand/clay detecting, electric resistivity tool for water/oil detecting, and neutron emitting tool for porosity detecting, accompanied by caliper for borehole width measurement and a corelation tool.
What the supercombo do is basically helping geologist and engineer on getting the characteristic of the borehole, feet by feet as it goes deeper. They can determine, based on the tool reading, where is the clay formation and where is the sand formation of the borehole. After they found the sand formations, they will determine, based on the tool reading, whether the sand holds up oil or water or a combination of both. After that, they will determine whether the porosity of the sand formation will hinder the flow of the formation or not.
All of these determinations, will in the end decide where the well will be perforated, and thus produced from. It’s also an important data to determine the relations of this well to its neighbouring (offset) wells.
Data is important, anywhere in the world.