近井地带润湿调控型清洗体系的构筑与性能评价研究

Construction and performance evaluation of wetting regulated cleaning system in near-well zone

针对致密砂岩油藏在水相圈闭、残留工作液、胶质沥青质沉积及油膜黏附等造成的近井壁污染问题,以脂肪醇聚氧乙烯醚和马来酸酐合成了一种新型润湿调控剂(GX),通过红外光谱仪、核磁共振仪对GX进行结构表征,并探究了其在亲油岩石的表面活性及吸附行为。以GX为核心构筑了润湿调控型清洗体系,对该体系的油膜剥离性能、降黏性能、解除水相圈闭伤害性能及储层保护性能进行了综合评价。结果表明,GX将油水界面张力降为0.11 mN/m,水滴接触角由130.45°降至70.01°,说明GX可将亲油/疏水的岩石表面调控为弱亲水/水下疏油状态。清洗体系可以有效促使油膜脱落。

A new wetting regulator(GX)is synthesized from fatty alcohol polyoxyethylene ether and maleic anhydride in laboratory to solve the pollution problems caused by water phase trapping damage,residual working fluid,colloidal asphaltene deposition and oil film adhesion in tight sandstone reservoir.The structure of GX is characterized by means of FT-IR and1H NMR,and its surface activity and adsorption behavior on oil-wet rocks are also investigated.A wetting-controlled cleaning system is constructed with GX as the core,and the system is evaluated comprehensively,including oil film stripping performance,viscosity reduction performance,water phase trapping removal performance and reservoir protection performance.The results show that GX reduces the interfacial tension between oil and water to 0.11 mN·m^(-1),and the contact angle of water droplets from 130.45°to 70.01°,indicating that GX can control the lipophilic/hydrophobic rock surface to a weak hydrophilic/hydrophobic state.The cleaning system effectively promotes the oil film to fall off.