一种基于阳离子稠化剂的高抗盐压裂液研究及应用

摘要

针对目前压裂作业向着高温油气藏措施改造、节约用水,利用海水、地层高矿化度水配液等非常规领域的拓展,通过对疏水缔合聚合物压裂液增黏机理研究,基于阴阳离子电吸引原理,开发研制了自缔合高抗盐压裂液体系,并对其进行了性能评价和现场应用.研究表明,在阳离子聚合物溶液中加入阴离子表面活性剂十二烷基苯磺酸钠,可以使聚合物分子通过静电吸引作用进行自缔合交联,并通过在分子中引入球状胶束及钙镁离子稳定剂,大幅度增强压裂液的抗温抗盐性能.该压裂液体系黏度可以达到331 mPa·s,耐盐达60 000 mg·L-1,有良好的抗钙镁性能,岩心伤害性低,在130℃、170 s-1剪切lh后黏度保持在50 mPa·s以上,可以满足60～130℃水温配液和压裂施工的要求;并且该压裂液在剪切速率上升时黏度降低,剪切速率下降时黏度又会恢复,可以有效降低摩阻.该体系在华北油田二连地区阿尔3-26井现场应用,采用矿化度达到9 104 mg·L-1的邻井地层水直接进行配液,提高了施工效率,增油效果显著.体系原料易得、成本价格低,抗盐性明显优于其他压裂液体系,具有良好的应用前景.%In view of the current fracturing operations toward high-temperature oil and gas reservoir measures,water saving,mixmg fracturing fluid by seawater or high salinity water,and other unconventional areas of development based on the study of the mechanism of hydrophobic associative polymer fracturing fluid,a self-association high salt-resistant fracturing fluid system was developed using the principle of anion and cation suction.Performance evaluation and field application of this kind of fracturing fluid system were carried out.Results show that addition of the anionic surfactant named dodecylbenzenesulfonic acid to the cationic polymer solution made the polymer molecules occur self associative reaction of electrostatic attraction;the addition of spherical micelles,calcium and magnesium ion stabilizer,enhanced the anti-temperature and salt resistance performance of the fracturing fluid.The fracturing fluid system viscosity can reach 331 mPa.s,it's salt resistant to 60,000 mg·L-1 and it has good resistance to calcium and magnesium,the core damage is lower than other fracturing,and the viscosity can be maintained above 50 mPa·s at 130 ℃and 170 s1 shear 1h,which can meet the requirements of water temperature distribution and fracturing construction at the temperature of 60-130 ℃.Moreover,the viscosity of the fracturing fluid decreases with the increase of shear rate and the viscosity will be restored when the shear rate decreases,this shows that it can effectively reduce the friction resistance.The system is applied in the field of 3-26 well in the Erlian of North China oil field,It uses the mineralization degree of 9,104 mg.L-1 of the formation of water directly to the liquid,which can improve the construction efficiency and increase the oil effect obviously.This system is easy to get raw materials,low cost,salt resistance is better than other fracturing fluid system,so it has a good application prospect.