Preparation and Field Test of Binary Complex Foam Agent COG

The foaming agents applied to the high-temperature and high-salinity wells in South Pingqiao Block prove to be ineffective, a foaming agent readily applicable to this block was thus prepared to address this problem. Cocamidopropyl betaine (CAB), dodecyldimethylamine oxide (OB), and hydroxypropyl guanidine gum (Guar) were adopted as raw materials to prepare a binary composite foaming agent COG. The influences of the mass ratios of CAB, OB, and Guar on the foaming performance of COG were analyzed by the orthogonal test method, and their optimal dosages was determined. The foaming properties, foaming stability, temperature resistance, and salt resistance of the proposed foaming agent COG were evaluated in the laboratory, and its comprehensive performance was significantly better than that of the two foaming agents commonly used in the field at the temperature of 95 ℃ and the salinity of 10 × 10⁴ mg/L. The test results of three wells in South Pingqiao Block showed that the foaming agent COG provided a favorable effect of drainage production stimulation, with the single-well gas production more than 10% higher than that obtained with the previous foaming agents. In research results show that the proposed binary composite foaming agent COG is suitable for the foam drainage of the shale gas wells in South Pingqiao Block, and it has high popularization and application value.