There are varying degrees of oils in and on the skin. Oils are produced by certain special glands in the skin. Some individuals have more glands than others. Some individuals have thicker oils than others. The oil if thin makes the skin feels oily. If the oils are thick, the skin feels greasy.
Oily skin is usually associated with large pores. Pores are the opening of tubes. These tubes connect the glands and the skin and
can become plugged with oils, especially if they re thick. Bacteria then populate the backed up pores. In some cases, various forms of acne can occur.