Multiple completion:

An arrangement for producing a well in which one wellbore penetrates two or more petroleum-bearing formations.

In one type, multiple tubing strings are suspended side by side in the production casing string, each a different length and each packed to prevent the commingling of different reservoir fluids.

Each reservoir is then produced through its own tubing string.

Alternatively, a small-diameter production casing string may be provided for each reservoir, as in multiple miniaturized or multiple tubingless completions.