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: An apparatus for placing a filter screen and for packing gravel around the filter screen adjacent a well formation. The apparatus includes a body having a packer portion and a valve portion. The body defines a central passageway therethrough. The valve portion includes a valve mandrel with a valve sleeve slidably positioned therein, and transverse openings in the valve sleeve and valve mandrel are aligned to form a transverse passageway therethrough when the valve is in an open position. A stinger is positionable in the body for closing the central passageway and actuating the valve sleeve between the open and closed positions thereof. When in the open position, the transverse openings in the valve mandrel and valve sleeve are aligned with a transverse opening in the stinger such that fluid communication is provided between a well annulus below the packer portion and the tool string above the apparatus. Collet fingers engage the stinger so that when the stinger is moved from the body, the valve is closed.

Abstract: A method of mixing fluids in a well bore employing a tubing string with a mixing valve disposed thereon. The well bore is sealed below the mixing valve, a first fluid then being pumped down the tubing string and a second fluid being pumped down the well bore annulus. By varying pressures and through the optional use of a circulating valve in conjunction with the mixing valve, the fluids may be mixed in the well bore or in the tubing string.

Abstract: A mixing valve for use in cementing, fracturing or other treatment of a well. The valve, which may be mounted in a pipe string, comprises a center mandrel surrounded by a coaxial housing having circumferentially spaced apertures therethrough. A packer cup surrounds the center mandrel below the apertures in the housing, and seals the annulus between the mandrel and housing when the pressure of fluid through the bore of the mandrel exceeds that on the outside of the chamber. When mixing fluids, it is only necessary to pressure the fluid outside the housing to collapse the packer cup against the mandrel, the fluid from the outside then entering the stream flowing from the mandrel bore. A method of mixing fluids utilizing the valve of the present invention is also disclosed.

Abstract: A seal system for a wellhead isolation tool diffuser utilizing elastomeric cup-shaped seals installed on the exterior of the diffuser, which is inserted into the production tubing at the wellhead. After insertion of the diffuser, the production tubing is pressurized, and the seals are set against the interior of the production tubing by the pressure in the well, effecting a tight seal.