Formation pressure is important information for well planning and operation because it impacts on several things as well control, casing design, drilling fluid program, pore pressure prediction, etc. We will discuss about formation pressure in a basic term for drilling personnel.
During an era of sedimentation and erosion, little grains of sediment are constantly building above each other, usually in an environment of full irrigation. As the sediment thickness of the base layer increases, the sediment grains are packed strongly near to each other, and some water is excluded from the small pore spaces. Though, if the pore spaces through the deposit sediments are connected to the top pressure surface, the fluid at any depth in the sediment will be same as that which would be found in a simple column of fluid.