摘要
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实验研究。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。
Abstract
Compared with onshore oilfield, the platform space of offshore oilfiled is limited，which require higher demands for polymer injection device process and dissolution time. According to the actual demands of offshore oilfields, the performance evaluation of "soluble instant" polymer solution and Cr3+ polymer gel was carried out under the LD10-1 oilfield geological and fluid conditions from aspects of production solubility, viscosity, rheology, viscoelasticity, molecular clew dimension, and flow characteristics. The results showed that "soluble instant" polymer was better in solubility than "high molar mass" polymer, and possessed excellent viscosity, rheology and viscoelasticity properties under the Bohai main oilfield conditions. Compared with the "linear branched" structure of polymer configuration, polymer molecules in Cr3+ polymer gel mainly aggregate with a "local reticular" structure which was less flexible and more rigid, making the flow resistance be enlarged. In the succeeding water-flooding, the dilution effect of injection water leaded to the molecular clew dimension of Cr3+ polymer gel detained in core pore increase and the increment of flow resistance was larger than the decrement caused by the outflow of polymer retained in pore core, which made the higher injection pressure of Cr3+ polymer gel and the residual resistance coefficient larger than the resistance coefficient, showing peculiar permeability characteristics from common polymer solution.
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