Thus, the fluid generated is called "supercritical fluid".

The first fluid is the sheath fluid.

A fluid reservoir (14) is fluidically coupled to the fluid input.

The treating fluid may be a fracturing fluid under or an acidizing fluid.

A fluid source is configured to join with the fluid connector and supply a fluid to the fluid channels.

The housing comprises a fluid inlet, a fluid outlet, a closed fluid treatment zone disposed between the fluid inlet and the fluid outlet.

The apparatus further includes a test fluid container in fluid communication with the fluid inlet, and a collection container in fluid communication with the fluid outlet.

The secondary fluid circuit has a secondary fluid separate from the primary fluid circulating therein.

Criterion 3 — Refrigerant and secondary refrigerant

The base fluid may be, but is not limited to a drilling fluid, a completion fluid, a production fluid, and/or a stimulation fluid.

A pad fluid may first be introduced into the formation, the pad fluid containing a gaseous fluid and, optionally, an aqueous fluid.

The fluid flow channel extends between the fluid inlet and the fluid outlet.

The fluid reservoir includes the suction fluid.

The second fluid channel operatively intersects (26) the first fluid channel for introduction of the second fluid into the first fluid channel.

The second fluid circuit cools the first fluid using the free-cooled second fluid.