Application of an integrated approach based on multi‐objective preference in the design and performance evaluation of efficient defoamers

Abstract A probability‐based approach for multi‐objective optimization is employed to develop efficient defoamers, addressing the challenges of drilling fluid foaming and the complex task of synergistically optimizing multiple performance indices of existing defoamers. An L 16 (4 3 ) orthogonal array (comprising 16 experimental runs with 3 factors at 4 levels each) is selected for the optimization process. The evaluation factors include the ratio of polyoxyethylene polyoxypropylene glycerol polyether (GPE) to polypropylene glycol (PPG), reaction temperature, and reaction time. The evaluation indicators encompass the stationary defoaming time and density recovery of freshwater and saline slurries at both room and elevated temperatures. Each performance indicator is classified as either favourable or unfavourable. Partial and total preference probabilities are calculated for each attribute. The optimal preparation plan is identified through screening, yielding a GPE:PPG ratio of 1:1, a reaction temperature of 80°C, and a reaction time of 2 h. Experimental results demonstrate that the defoamer effectively eliminates foam in drilling fluids at dosages ranging from 0.2% to 0.3%, outperforming typical commercially available defoamers. The defoamer achieves a density recovery rate exceeding 81% for both freshwater and saline slurries at room and high temperatures. Characterization via infrared spectroscopy, thermal stability assessments, and fluorescence testing confirms that the defoamer retains excellent performance under the complex working conditions encountered in drilling fluids, showcasing strong adaptability.