Experiments on Blocking Ability of Nitrogen Foam and Its Application in Anti-Water-Coning

Abstract

Foams have been used successfully in oilfields as a diverting agent to decrease mobility of the gas phase and to control channeling of the water phase in heterogeneous porous media. A series of experiments and numerical simulations focused on foam blocking ability and anti-water-coning technology. The experiments were carried out to measure foaming ability in order to optimize foaming agents. This article discusses the results from several experiments in which factors such as foaming agent concentration, permeability, oil saturation, and gas–liquid ratio were varied systematically to evaluate foam blocking ability. The mechanics of nitrogen foam anti-water-coning are analyzed according to the results of experiments. In order to quantitatively evaluate the production performance by nitrogen foam anti-water-coning, a numerical simulation method was employed to determine the optimal nitrogen injection time, shutting-in time, daily fluid production, nitrogen foam injection method, and nitrogen foam injection occasion. The results of numerical simulations show that nitrogen foam can effectively repress water-coning and allow incremental oil production in a bottom water reservoir.