新型两性非离子型泡排剂在下古气藏的试验与应用

Test and application of new amphoteric-nonionic foaming agents in Lower Palaeozoic gas reservoir

大牛地气田下古气藏地层水矿化度高、呈偏酸性,多采用井下节流工艺,导致气田广泛使用的两性泡排剂起泡、稳泡性能差,无法满足高效、低成本排水采气的需求。国内外虽已形成几十种泡排剂,但针对大牛地气田下古气藏特性研制的泡排剂未见报道。针对下古气藏流体和工艺特点,考虑高矿化度地层水的影响、对pH的敏感度及泡沫通过节流器时的稳定性等因素,构建一种以磺化AEO3(椰油醇聚氧乙烯(3)醚)与月桂酰胺丙基磷酸甜菜碱为主剂、椰子油脂肪酸单乙醇酰胺为助泡剂、油患子精华素为稳泡剂的新型两性非离子复合型泡排剂。室内评价表明,两性非离子复合型泡排剂在高矿化度、酸性环境下具有较强的起泡、稳泡、二次起泡和携液能力;现场试验应用后,气井排液能力提升、油套压差降低、产气量增加,应用效果和经济效益前景良好。两性非离子复合型泡排剂填补了大牛地气田下古气藏泡排剂的空缺,可改善下古气藏气井携液不足的技术难题,具有推广应用价值。

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 characteristics 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 AEO3and 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, stabilizingfoam, 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.