Abstract: A composite fracturing fluid consisting of a mixture of carbon dioxide liquid, nitrogen gas and an aqueous media. Nitrogen is present in the mixture in an amount from about 1.25 to about 15 parts by volume to about 1 part by volume carbon dioxide, and nitrogen and carbon dioxide are present in the mixture from about 1 to about 24 parts by volume to about 1 part by volume water at bottom hole conditions in a subterranean formation. Thickening agents, gelling agents, foaming agents, surfactants, cross-linking agents, proppants, and other additives may be mixed with the fluid to achieve fluid properties desired for various types of subterranean formations.

Abstract: An air lift diffuser for use in the aeration of a body of water including an air lift tube and a gas diffuser located a distance below the open bottom end of the air lift tube. The distance in question is sufficiently large that there is substantially no obstruction to the passage of water from the space surrounding the air lift diffuser into the space between the air lift tube and the diffuser, but at the same time is not so large that rising air bubbles are likely to escape and flow outside the air lift tube. In one embodiment, a cylindrical return tube is provided around the air lift tube that directs the water stream and gas bubbles entrained therein downward, after they have risen in the air lift tube, so as to return the aerated water to the lower levels of the body of water being aerated.

Abstract: A diffuser for dispersing gas into a body of liquid that may contain suspended solids. Under ordinary clogging conditions, the diffuser will remain operative over an indefinite period of time by reason of large gas outlet openings at the bottom of the gas plenum chamber. In addition, it can be employed for a good portion of that time to disperse a substantial flow of coarse bubbles and fine bubbles, in a desired combination, simultaneously from a single gas plenum. Careful selection of the permeability and area of a top porous wall of a gas plenum chamber, together with proper selection of the level, size and number of coarse bubble gas outlet openings in the side walls of the plenum chamber, achieve the second feature.

Abstract: A fluid diffuser for dispersing a gas or liquid into a body of receiving liquid in which it is immersed. The diffuser includes a rotatable shaft, a thin disk-like member mounted for rotation on the shaft, and an annular ring positioned adjacent the outer perimeter of the disk-like member. At least one of the top and bottom walls of the annular ring is porous. These top and bottom walls define a fluid plenum, into which gas or liquid under pressure is introduced to be emitted from the plenum as small, nascent fluid spheroids on the surface of the annular ring. The boundary layer flow from rotation of the disk-like member within the body of receiving liquid shears fine gas bubbles or liquid particles from the foraminous surface or surfaces of the annular ring. The annular ring may be fixed, or rotatable in the opposite annular direction from the rotation of the disk. Impeller blades may be mounted on the top and/or bottom surfaces of the rotatable disk.

Abstract: A mixer for mixing a body of receiving liquid with solids, liquids or gases introduced therein. The mixer includes a rotatable shaft, a thin disk-like member mounted for rotation on the shaft, and at least one thin annular ring mounted on the disk-like member spaced from, parallel to and concentric with it. The flow of liquid perpendicular to the annular ring through the inner opening thereof, when the mixer is immersed and rotating in the body of receiving liquid, is unimpeded by any structural member. The annular ring may be mounted on either side of the disk, and a plurality of annular rings may be employed. The annular ring or rings may be mounted on the disk-like member by at least three elongated support posts spaced equally around the outer perimeter of the disk, the transverse cross-section of each post being curvilinear, preferably circular, in shape. The mixer is disclosed for use in a tank.