What Does Core Diameter Mean?
Core diameter is the diameter of the core barrel that retains rock or soil core samples obtained during the drilling operation. There are different types of core barrels but the standard one used is the double core tube barrel that is capable of isolating the sample from the drilling fluid stream.
Core samples are very important for sampling and conducting soil investigation in order to select appropriate boring methods for laying pipelines.
Trenchlesspedia Explains Core Diameter
Trenchless methods such as horizontal directional drilling (HDD), horizontal auger boring (HAB), microtunneling and pipe jacking use different types of drill bits and cutters to bore through soil or rock. Since the boring process is carried out underground and out of sight, it is very essential to understand the soil characteristics that exist in the bore path.
Boring blindly can cause damage to the equipment and even lead to failure of the pipeline project. Core barrels are used to bring up rock samples from the drilling operation. Single tube core barrel is the least expensive and most sturdy one with a head section, core recovery tube, a reamer shell and cutting bit.
The standard and most preferred is the double tube core barrel in which the outer barrel rotates with the cutting bit while the inner barrel retains the core sample and is either fixed or swivels on bearings. The core diameters range from 21-85 mm.