High energy foaming technique on horizontal wells in Yulin gas field

In order to extend the flowing duration and increase the efficiency of natural gas extraction of horizontal gas wells, high-energy foaming technique including authigenic N₂ compounds is developed in this paper. By comparative analysis, indoor testing and on-site testing, the optimized formulation of high-energy agent is screened and high effectiveness is proved by the on-site experiment. The results demonstrate that the N₂-type self-generated gas exhibits optimal properties in terms of aqueous solubility, pH, and foaming capacity among commonly used self-generated gases. Furthermore, the highly exothermic nature of the N₂-generating reactions and their by-products lead to significant alterations in the water quality of the experimental gas wells. Based on a comparison of the foaming properties of various agents, Gemini surfactant is selected as foaming agent. This high-energy foaming technique is applied to the on-site experiment and the gas production of the experiment horizontal gas well is significantly increased, better than the existing drainage technologies in the Yulin gas field. The experimental results show the daily average gas production is 4.71×10⁴ m³, and cumulative gas production is 37.60×10⁴ m³.