Sedimentary facies interpretation of Gamma Ray (GR) log as basic well logs in Central and Lower Indus Basin of Pakistan

Rocks and most type of soils emit Gamma Ray (GR) in varying amount. The emitting elements of primary gamma radiations include potassium 40, uranium, and thorium which are associated with rocks forming minerals in variable amount. GR log is used to predict the varying lithology in borehole by measuring the spontaneous emission of GR radiation from rocks. Role of GR logs in the identification of subsurface facies is the main focused research theme of this manuscript including with objective of brief introduction of GR log and its applications in the identification of facies in the field of Petroleum Geosciences by analyzing the examples of GR log(s) from wells, Lower Indus Basin, Pakistan.