Downhole foam generator

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. The pressure drop across the choke and increase in gas velocity immediately therebelow in the body creates a low pressure area, into which the liquid in the annulus is drawn through the apertures in the foam generator, the resulting turbulence creating a substantially homogeneous fine-textured foam which continues down the tubing string to exit in the vicinity of the well bore to be treated.

Dependencies are inferred from the claim text.