At present,the deterioration mechanism of foam drilling fluids has been widely studied at normal temperature and pressure, while there are few researches at high temperature. This paper described the stabilization mechanisms of LAS series surfactants at high temperature. The impact of surfactant structure,surface visco-elastic behavior and interfacial film distribution on foam high temperature property were conducted using molecular simulating and foam core plugging method. And the results were compared with that at low temperature. The results showed that the stability is mainly dependent on the hydrophilic head of surfactant when the temperature is lower than 100 ℃. The stability is mainly dependent on the twisting degree and hydrophobic tail of surfactant when the temperature is higher than 100 ℃. The foam is more stabilized with the higher degree of hydrophobic chain curl because the tail chain intertwined more complexly. The higher the temperature, the wider the surfactant head group distributes. The foam is more unstable because the interconnection up and down is more obvious. This is the reason the stability of foam is becoming worse with the increase of temperature.%目前,对泡沫钻井流体在常温常压条件下的衰变机理研究较多,但对其高温稳定性的研究较少.通过试验研究了头基相同的LAS系列表面活性剂泡沫的高温稳定机理.采用分子模拟和泡沫岩心封堵法,从表面活性剂结构、表面黏弹性、界面膜的分子排布等方面对泡沫的高温性质进行了深入研究,并与其低温性质进行了对比.研究发现,当温度低于100℃时,泡沫稳定性主要受表面活性剂极性头的影响；当温度高于100℃时,泡沫稳定性主要取决于表面活性剂的疏水尾及其缠绕程度,其疏水链卷曲程度越高,尾链相互缠绕交错越复杂,泡沫稳定性越强；温度升高,表面活性剂头基分布变宽,上下交错现象明显,界面变得粗糙,泡沫膜越容易破裂,这是温度升高泡沫稳定性变差的原因之一.
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