新型页岩气储层保护剂SDME-2的制备及特性

Preparation and Performance of Novel Reservoir Protection Agent SDME-2 Used for Shale Gas Reservoirs

页岩气钻探开采过程中,钻井液滤液侵入页岩储层易导致严重的水敏损害和液相圈闭,严重影响了页岩气地层钻井安全及页岩气产能。针对页岩气储层特性及储层损害主要因素,基于纳米乳液制备理论及页岩储层保护基本原理,利用Gemini季铵盐型表面活性剂GTN、Tween80、正戊醇和正辛烷作为主要原料,制备出了纳米乳液储层保护剂SDME-2。性能评价结果表明,SDME-2具有超低的界面张力,可使页岩表面由水湿转变成中性润湿,显著降低岩心残余水饱和度,提高超低渗页岩岩心渗透率恢复值,降低储层水锁伤害;可显著降低页岩对甲烷的吸附量,有利于甲烷分子的低压解吸。以纳米乳液SDME-2作为储层保护剂,构建了页岩气储层保护水基钻井液。性能评价结果表明,该钻井液流变性良好,抑制性强,具有优良的储层保护性能。

Water sensitive damage and liquid trap caused by water-based drilling fluid invasion are very prominent problems in the process of shale gas drilling and exploitation,which seriously affect drilling safety and production of shale gas well.According to the shale gas reservoir characterization and reservoir damage factor,based on nanoemulsion theory and basic reservoir protection principle,a novel nanoemulsion agents named SDME-2 were developed by employing Gemini hyamine surfactant GTN,plus Tween 80,n-amyl alcohol and n-octane as major raw materials.The results showed that the novel nanoemulsion agent could effectively reduce the surface tension of external fluid,increase contact angle,decrease water saturation in core,and increase recovery of low permeability reservoir permeability.The novel nanoemulsion agent was also conducive to shale gas desorption.Taking the newly developed shale gas reservoir protection agent as one of primary treatment agents,a new type of water-based drilling fluid for shale gas reservoir protection was developed and its performance was good.