蒸汽驱用耐高温发泡剂研究

A Study on high-temperature resistant Foaming agent Used for Steam flooding

泡沫辅助蒸汽驱可提高稠油的采收率,关键在于研发具有优良高温稳定性和高温发泡性能的专用表面活性剂。本文研制了一种耐高温发泡剂DQS体系,考察了作为蒸汽驱用耐高温发泡剂的性能及其在蒸汽/泡沫驱油双管模拟实验的应用效果。该体系由99.7%妥尔油脂肪酸钠盐和0.3%疏水缔合聚丙烯酰胺EPS30R组成,在250～300℃范围内的高温半衰期可达223 min,降解率仅为6.17%,适宜的使用浓度为12 g/L。在250℃和300℃高温下,向3.8 cm×60 cm的填砂管(气测渗透率4μm2)中以5 mL/min的流量注入3.5 g/L DQS溶液时,封堵压差可稳定在2.0 MPa以上;地层含油饱和度<10%、岩心渗透率高于13μm2时,DQS体系(12 g/L)的封堵效果较好;该体系(5 g/L)在储层岩石表面上的吸附损失量较少,仅为26%。蒸汽/泡沫驱油双管模型实验表明,在非均质孔隙介质中,该体系可封堵高渗区域内的蒸汽窜流通道,使高渗区域内蒸汽因渗流阻力增加而转向进入低渗区域,从而明显提高低渗区域的驱油效率。

It is critical to research special surfactant with good thermal stability and foaming property for Steam-foam flooding.In this paper,a kind of high-temperature resistant foaming agent DQS was prepared,composed of 99.7% tall oil fatty acid sodium and 0.3% hydrophobically polyacrylamide（EPS30R）.The results of experimental evaluation of performance properties were presented.Within the temperature of 250～300℃,its high-temperature half life was 223 min,degradation rate was 6.17%,and the appropriate application concentration was 12 g/L.When 3.5 g/L DQS solution was injected into φ3.8 cm×60 cm sand pack of gas permeability 4 μm2 at 5 mL/min flow rate,plug pressure difference of DQS system under 250℃～300℃was steady up to 2.0 MPa.The plugging effect of 12 g/L DQS system was good when formation oil saturation was below 10% and core permeability was above 13 μm2.The mass loss of DQS adsorption by reservoir rock surface was as low as 26%.The double parallel tube model test for steam/foam flooding confirmed that injected steam was diverted by foam from high permeability area to low permeability area,therefore,oil displacement efficiency in low permeability area was improved significantly.