Casing and tubing are both Oil Country Tubular Goods, but they do different jobs in a well. Casing is the larger-diameter pipe that lines the drilled wellbore, cemented in place to hold the hole open, seal off formations, and protect groundwater. Tubing is the smaller-diameter pipe run inside the casing, through which oil or gas flows to the surface. A single well uses several casing strings of decreasing diameter as it gets deeper, then a tubing string for production.
For shipping, the distinction matters because of size and weight. Casing joints are heavier and wider, often moving as breakbulk or on flat racks, while tubing can sometimes consolidate into standard or open-top containers. Both ship with thread protectors and corrosion coating intact. Texas International Freight handles OCTG of every string and grade.
