Mud logging, also known as surface logging, is the creation of a detailed record of a borehole by examining the bits of rock or sediment brought to the surface by the circulating drilling medium (most commonly Drilling Fluids “Mud”). Mud logging is usually performed by a third-party mud logging company such as “Baker, ECS, Petro-Services”. This provides well owners and producers with information about the lithology and fluid content of the borehole while drilling as well as all drilling parameters & downhole problems. Historically it is the earliest type of well log instead of the Open Hole Logging (OHL) &/ Logging While Drilling “LWD”.