1. n. [Enhanced Oil Recovery]

A laboratory device used to indicate miscibility between reservoir oil and injection gas. A gas bubble is injected into an oil-filled visual cell at a given temperature and test pressure. The change in shape of the rising bubble indicates its miscibility with the oil at those conditions. Below the minimum miscibility pressure (MMP), the bubble holds its shape as it rises. Above the MMP, the bubble shape changes as it rises; it may disintegrate, dissolve or disappear into the oil. Testing at several pressures helps determine the MMP between the gas and oil. The rising-bubble test represents a forward-contacting miscibility process and therefore may not accurately estimate the MMP for a backward or combined contact mechanism.

See: backward multiple-contact test,  forward multiple-contact test,  minimum miscibility pressure,  slim-tube test