Scratching devices as casing scratchers are external devices designed to remove immobile mud from the wellbore and mud cake from the wellbore wall (Fig. 1). These devices are categorized by how aggressive they are. Casing Scratchers Types The basic springloaded bristle scratcher is more aggressive than the cable scratcher (also known as a wellbore wiper). … Continue reading Casing Scratchers Overview In Wells Cementing