The formation water of Lower Palaeozoic gas reservoir in Daniudi Gas Field is high-salinity and acidity

and downhole throttling technology is mostly used. Thus

the amphoteric foaming agents widely used in gas fields has poor foaming and foam stabilization performance

and this cannot meet the demand for high-efficiency and low-cost drainage gas recovery. Although dozens of foaming agents have been formed internationally

there is no reports about foaming agents developed for the characteristics of Lower Palaeozoic reservoir of Daniudi Gas Field. Considering the fluid and process charact

eristics of Lower Palaeozoic reservoir

and the influence of high-salinity formation water

the sensitivity to pH and the stability of foam passing through the choke

to construct a new type amphoteric-nonionic compound foaming agent with sulfonated AEO

3

and lauramide propyl phosphobetaine as the main agent

coconut oil fatty acid monoethanolamide as the foaming aid

and sapindus extract as the foam stabilizer. The indoor evaluation shows that the amphoteric-nonionic composite foaming agent has strong foaming

stabilizing-foam

secondary foaming and liquid-carrying ability under high-salinity and acidic; after the field test application

the well drainage capacity improved

the pressure difference with tubing to casing decreased

and the gas production increased. It is shown that its application effect and economic benefits prospects are good. The amphoteric-nonionic composite foaming agent fills the void of the foaming agent for Lower Palaeozoic gas reservoir in Daniudi Gas Field

improving the technical problems of insufficient liquid-carrying

and has the value of popularization and application.