Summary Polymer flooding is a mature chemical enhanced oil recovery (EOR) technology with more than 40 years of laboratory- and field-scale applications. Nevertheless, polymers exhibit poor performance in carbonates owing to their complex nature of mixed-to-oil wettability, high temperature, high salinity, and heterogeneity with low permeability. The main objective of this study is to experimentally evaluate the performance of a potential biopolymer (scleroglucan) in carbonates under harsh conditions of high temperature and high salinity. This experimental investigation includes polymer rheological studies as well as polymer injectivity tests. Rheological studies were performed on the biopolymer samples to measure the polymer viscosity as a function of concentration, shear rate, salinity, and temperature. Injectivity characteristics of this biopolymer were also examined through single-phase corefloods using high permeability carbonate outcrops. The injectivity tests consisted of two stages of water preflush and polymer injection. These tests were conducted using high salinity formation water [167,000 ppm total dissolved solids (TDS)] and seawater (43,000 ppm TDS) at both room (25°C) and high temperature (90°C) conditions. The rheological tests showed that the biopolymer has a high viscosifying power, and it exhibits a shear-thinning behavior that is more prevalent at higher polymer concentrations. Also, a pronounced effect was observed for water salinity on both polymer filterability and injectivity. Moreover, the biopolymer exhibited better filterability at the high temperature as opposed to the room temperature. From the injectivity tests, the shear-thinning behavior of this biopolymer in the porous media was confirmed as the resistance factor (RF) decreased with increasing the flow rate applied. The potential biopolymer showed good injectivity at both the room and the high temperatures. A limited number of studies have evaluated the rheological and injectivity performance of this newly developed EOR grade scleroglucan biopolymer in carbonates under harsh conditions of high salinity and high temperature. Most of the previous studies were performed in sandstones under relatively mild salinity and temperature conditions. Hence, this study provides further insight into the performance of this biopolymer and encourages application in carbonates under harsh salinity and temperature conditions.

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硬葡聚糖生物聚合物在苛刻条件下的流变学和注入性研究

总结 聚合物驱是一种成熟的化学强化采油 (EOR) 技术，在实验室和现场规模的应用中已有 40 多年的历史。然而，聚合物在碳酸盐中表现出较差的性能，因为它们具有混合油润湿性、高温、高盐度和低渗透率的非均质性等复杂性质。本研究的主要目的是通过实验评估一种潜在的生物聚合物（硬葡聚糖）在高温和高盐度的苛​​刻条件下在碳酸盐中的性能。该实验研究包括聚合物流变学研究以及聚合物注入测试。对生物聚合物样品进行了流变学研究，以测量聚合物粘度随浓度、剪切速率、盐度和温度的变化。这种生物聚合物的注入特性也通过使用高渗透性碳酸盐露头的单相岩心驱替进行了检查。注入性测试包括水预冲洗和聚合物注入两个阶段。这些测试是在室温 (25°C) 和高温 (90°C) 条件下使用高盐度地层水 [167,000 ppm 总溶解固体 (TDS)] 和海水 (43,000 ppm TDS) 进行的。流变测试表明，该生物聚合物具有较高的增粘能力，并且在较高的聚合物浓度下表现出更普遍的剪切变稀行为。此外，观察到水盐度对聚合物过滤性和注入性的显着影响。此外，与室温相比，生物聚合物在高温下表现出更好的过滤性。通过注入性测试，这种生物聚合物在多孔介质中的剪切稀化行为被证实为阻力因子 (RF) 随着应用流速的增加而降低。潜在的生物聚合物在室温和高温下均表现出良好的注入性。有限数量的研究评估了这种新开发的 EOR 级硬葡聚糖生物聚合物在高盐度和高温的苛刻条件下在碳酸盐中的流变性和注入性能。大多数先前的研究是在相对温和的盐度和温度条件下在砂岩中进行的。因此，这项研究进一步深入了解了这种生物聚合物的性能，并鼓励在苛刻的盐度和温度条件下应用于碳酸盐。这种生物聚合物在多孔介质中的剪切稀化行为被证实为阻力因子 (RF) 随着应用流速的增加而降低。潜在的生物聚合物在室温和高温下均表现出良好的注入性。有限数量的研究评估了这种新开发的 EOR 级硬葡聚糖生物聚合物在高盐度和高温的苛刻条件下在碳酸盐中的流变性和注入性能。大多数先前的研究是在相对温和的盐度和温度条件下在砂岩中进行的。因此，这项研究进一步深入了解了这种生物聚合物的性能，并鼓励在苛刻的盐度和温度条件下应用于碳酸盐。这种生物聚合物在多孔介质中的剪切稀化行为被证实为阻力因子 (RF) 随着应用流速的增加而降低。潜在的生物聚合物在室温和高温下均表现出良好的注入性。有限数量的研究评估了这种新开发的 EOR 级硬葡聚糖生物聚合物在高盐度和高温的苛刻条件下在碳酸盐中的流变性和注入性能。大多数先前的研究是在相对温和的盐度和温度条件下在砂岩中进行的。因此，这项研究进一步深入了解了这种生物聚合物的性能，并鼓励在苛刻的盐度和温度条件下应用于碳酸盐。