Commingled is to mix fluids from more than one source. Commingling can be the mixing of production from different reserviors in the same well or production from different wells.
Commingled well is a well that produces from two or more different producing reservoirs. The gas or oil is mixed as it is brought up the well in a single string of tubing. A commingled well is in contrast to a multiple completion well in which the oil or gas from the different producing reservoirs is not mixed as it is brought up the well in separate strings of tubing and stored in separate tanks.