Foamed-Cement Characterization Under Downhole Conditions and Its Impact on Job Design

This paper reports on the engineering properties of foamed-cement slurries that were studied in detail with an original methodology based on new equipment. With this laboratory equipment, foamed cement can be mixed and characterized at pressures and temperatures representative of field conditions and at densities as low as 400 kg/m{sup 3}. The pressure and shear field under which a foam is generated are found to have a strong effect on bubble-size distribution (BSD), permeability, and to a lesser extent, compressive strength. Data on thickening time, fluid loss, and the effect of temperature on foam properties are also presented. A better understanding of foamed-cement properties allows optimization of job design so that prescribed pressure and density profiles in the column are achieved both during circulation and after placement. Critical design parameters are identified and their relative influence is shown through a case study.