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与陆地油田相比较,海上平台空间狭小,对聚合物配注设备工艺和聚合物溶解速度提出了更高要求。依据海上油田矿场实际需求,本文针对渤海主要油田油藏地质和流体条件,对“速溶”聚合物产品的溶解性及其聚合物溶液和Cr3+凝胶黏度特性、流变性、黏弹性、分子线团尺寸和渗流特性进行了研究。实验结果表明,在渤海主要油田油藏温度和溶剂水矿化度条件下,“速溶”聚合物溶解性优于“高分”聚合物,同时表现出较强的增黏性、流变性和黏弹性。与聚合物溶液中“线性支链状”聚集体相比较,Cr3+聚合物凝胶内聚合物分子以“局部网状”聚集体为主,柔性变差,刚性增强,渗流阻力增加。在后续水驱过程中,注入水稀释作用导致滞留岩心孔隙内Cr3+聚合物凝胶分子线团尺寸Dh增加,其增加的渗流阻力大于因部分滞留聚合物离开岩心而减小的渗流阻力,这导致Cr3+聚合物凝胶注入压力升高,残余阻力系数大于阻力系数,表现出与聚合物溶液不同的渗流特性。
Compared with the onshore oilfields, the space on the offshore platform is small, which puts higher demands on polymer dispensing equipment technology and polymer dissolution rate. According to the actual needs of offshore oilfield mines, this paper aims at the geophysical and fluid conditions of major oilfields in the Bohai Sea, the solubility of “instant ” polymer products, the viscosity characteristics of polymer solution and Cr3 + gel, rheological properties, viscoelasticity, Molecular coil size and seepage characteristics were studied. The experimental results show that under the conditions of reservoir temperature and solvent water salinity in the major oilfields of Bohai Sea, “instant ” polymer has better solubility than “high score ” polymer and exhibits strong viscosity increase, Rheology and viscoelasticity. Compared with the “linear branched” aggregates in the polymer solution, the polymer molecules in the Cr3 + polymer gel are dominated by “local reticular ” aggregates with poor flexibility, increased rigidity and increased resistance to seepage . During subsequent waterflooding, dilution of injected water leads to an increase in the molecular size Dh of Cr3 + polymer gel molecules in the retained core pores, which increases the seepage resistance greater than the reduced seepage resistance resulting from the partially retained polymer exiting the core, Cr3 + polymer gel injection pressure increases, the residual resistance coefficient greater than the resistance coefficient, showing the seepage characteristics and polymer solution.