Dirty cargoes comprise crude oil or heavy, viscous petroleum products (heavy fuel oil, for example, which coats the sides of the cargo tanks). Those petroleum products which leave significant amounts of residue in tanks. Generally applies to crude oil and residual fuel oil. Vessels carrying dirty cargoes may be referred to as dirty vessels
Sedimentary rock with clay minerals in pores, even small quantities of which can reduce porosity and permeability
A logging method that records deviation from the vertical
A wellbore intentionally drilled at an angle from the vertical
Intentional deviation of a wellbore from the vertical. Although wellbores are normally drilled vertically, it is sometimes necessary or advantageous to drill at an angle from the vertical. Controlled directional drilling makes it possible to reach subsurface areas laterally remote from the point where the bit enters the earth
