聚合物及聚合物/表面活性剂二元复合驱油体系在超长岩心中运移规律

Migration Rule for Polymer and Polymer/Surfactant Binary Compound Flooding System in Long Core

为了获得聚合物及聚合物/表面活性剂二元复合驱油体系在油层中真实的运移规律,采用J油田油砂建立15 m超长岩心物理驱油实验模型,利用现场在用聚合物3640(丙烯酰胺、丙烯酸共聚物,相对分子质量2000万,水解度20%,浓度1200 mg/L)和表面活性剂HDS(由α-烯烃磺酸盐与APG等表面活性剂按比例复配而成,浓度2000 mg/L)配制二元复合驱体系和聚合物体系,在油藏温度57℃条件下研究了二元复合体系和聚合物驱油体系的运移情况。研究结果表明:两种体系中聚合物浓度和黏度均随着运移距离的增大而降低,聚合物溶液的黏度损失程度比浓度更严重。二元复合驱与聚合物驱相比注入压力低,采收率提高4.94%,较低的界面张力(10^(-2)m N/m数量级)仅可维持约1/2井距的距离,最终界面张力值与聚合物溶液相近。二元复合体系与原油在岩心内可形成稳定的乳状液,随着运移距离增大,表面活性剂的吸附损失会导致乳状液发生破乳、聚并。

In order to probe the real migration role of the polymer and polymer/surfactant binary compound flooding system,two15 meter core models with oil sand of J oilfield were established,and the binary compound flooding system,composed of 1200 mg/L polymer 3640,a acrylamide/acroleic acid copolyler with relative molecular weight of 2000×10~4 and hydration degree of 20%,and1200 mg/L surfactant HDS,a complex of sodium alpha-olefin sulfonate and surfactant APG,and polymer flooding（1200 mg/L polymer 3640） displacing experiments were carried out under the condition of 57℃ and monitored by measurement of the concentration and viscosity of the samples obtained during displacing process at different pressure monitoring nodes. The results showed that polymer concentration and viscosity of two systems reduced with migration distance increasing and the viscosity lost more. Compared with polymer flooding,the binary compound flooding system had lower injection pressure and the enhanced oil recovery was 4.94% higher. Lower interfacial tension between the binary compound flooding system and the simulated oil maintained half of the distance,and finally it was close to that of polymer flooding. The binary compound system could form the stable emulsion with the simulated oil,when injected into the core. With the increase of migration distance,the adsorption loss of surfactant would lead to demulsification and coalescence of the emulsion. The migration rule based on the super-long core would provide effective parameters to guide the following scheme optimization and adjustment.