Abstract: A method of tracking material in a well comprises the steps of: (a) creating in a computer a model of the structure of the well, including defining a first plurality of sets of data to define sectors of a flow path in the well; (b) creating in the computer a first model of the material in the well, including defining a second plurality of sets of data to define initial conditions of material within the sectors; and (c) creating in the computer, in response to the first plurality of sets of data and the second plurality of sets of data, a second model of the material in the well, including defining a third plurality of sets of data of current conditions of material within the sectors.

Abstract: A system is provided for mixing of concentrated liquid gelling agent and water to form a fracturing fluid for fracturing of a subterranean formation. High shear rotary mixers are utilized in a blender tub to provide efficient hydration of the concentrated liquid gelling agent and water mixture.

Abstract: A mixing apparatus is provided for mixing slurries, particularly high density, high viscosity fracturing fluid slurries containing a large proportion of proppant material. A mixing tub has a generally round horizontal cross-sectional shape. A relatively large, low-speed rotating agitator is utilized to mix the slurry. The design of the agitator is such that a radially inwardly rolling toroidal shaped slurry flow zone is created adjacent the upper surface of the slurry within the tub. A stream of clean fracturing fluid is introduced into the tub near the center of the toroidal shaped flow zone. Dry proppant material is introduced into the tub and carried by the radially inwardly rolling flow into contact with the clean fracturing fluid. Foraminous baffles, preferably constructed from expanded metal sheets, are radially oriented within the tub to reduce rotational motion of the slurry within the tub without causing dropout of proppant from the slurry.

Abstract: A mixing apparatus is provided for mixing slurries, particularly high density, high viscosity fracturing fluid slurries containing a large proportion of proppant material. A mixing tub has a generally round horizontal cross-sectional shape. A relatively large, low-speed rotating agitator is utilized to mix the slurry. The design of the agitator is such that a radially inwardly rolling toroidal shaped slurry flow zone is created adjacent the upper surface of the slurry within the tub. A stream of clean fracturing fluid is introduced into the tub near the center of the toroidal shaped flow zone. Dry proppant material is introduced into the tube and carried by the radially inwardly rolling flow into contact with the clean fracturing fluid. Foraminous baffles, preferably constructed from expanded metal sheets, are radially oriented within the tub to reduce rotational motion of the slurry within the tub without causing dropout of proppant from the slurry.

Abstract: An apparatus for mixing a fluid includes a mixing tub having a substantially circular horizontal cross-sectional shape, and an agitator assembly associated with the mixing tub. The agitator assembly includes a drive shaft having upper and lower agitators attached thereto. The drive shaft is located within the tub and has a substantially vertically oriented axis of rotation. The lower agitator moves fluid generally downward through a radially inner cross-sectional area defined within a first radius swept by the lower agitator. The upper agitator moves fluid within the first radius generally radially outward as that fluid is moved generally downward by the lower agitator, and moves fluid outside the first radius generally upward. A plurality of foraminous baffles are mounted within the tub for reducing rotational motion of the slurry within the tub about the generally vertical axis of the agitator shaft.

Abstract: A mixing apparatus is provided for mixing slurries, particularly high density, high viscosity fracturing fluid slurries containing a large proportion of proppant material. A mixing tub has a generally round horizontal cross-sectional shape. A relatively large, low-speed rotating agitator is utilized to mix the slurry. The design of the agitator is such that a radially inwardly rolling toroidal shaped slurry flow zone is created adjacent the upper surface of the slurry within the tub. A stream of clean fracturing fluid is introduced into the tub near the center of the toroidal shaped flow zone. Dry proppant material is introduced into the tub and carried by the radially inwardly rolling flow into contact with the clean fracturing fluid. Foraminous baffles, preferably constructed from expanded metal sheets, are radially oriented within the tub to reduce rotational motion of the slurry within the tub without causing dropout of proppant from the slurry.

Abstract: A method and apparatus for generating foam in a well bore, the apparatus being a foam generator comprising a tubular body having a plurality of apertures circumferentially spaced about the wall thereof, the tubular body containing a choke therein disposed above said apertures as the foam generator is positioned in the well bore. The foam generator is located in a tubing string in the well bore, preferably with at least one stand of tubing between it and the area of the well bore to be treated with the foam. The liquid component of the foam, which may or may not carry solid particles such as fracturing proppants, is pumped down the well bore annulus, while the gaseous component of the foam is introduced through the tubing string.

Abstract: The present invention relates to a method of fracturing subterranean formations and placing proppant material in the created fracture utilizing carbon dioxide or nitrogen containing fluid. An aqueous liquid-liquid carbon dioxide emulsion fluid is prepared having an internal phase ratio in the range of from about 50 to in excess of about 96 percent and introduced into the subterranean formation to be fractured. The emulsion is heated by the formation to a temperature above the critical temperature of carbon dioxide and the carbon dioxide is caused to be converted to a vapor whereupon the emulsion becomes a foam. The volume of liquid carbon dioxide is adjusted as the volume of proppant material varies to at least substantially maintain a constant internal phase ratio in the treatment fluid. When nitrogen is utilized, a foam is produced on the surface by admixing gaseous nitrogen with the gelled fluid. The formation is fractured by the treatment fluid and the proppant is placed in the created fracture.