Characterization of Ultra-High Molecular Weight Oilfield Polymers for Optimal Chemical Enhanced Oil Recovery Performance and Reuse of Produced Water

超高分子量油田聚合物的表征，以实现最佳化学强化采油性能和采出水的再利用

• 批准号: RGPIN-2015-05581
• 负责人: Trivedi, Japan
• 金额: $ 1.82万
• 依托单位: University of Alberta
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2018
• 资助国家: 加拿大
• 起止时间: 2018-01-01 至 2019-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=667156
• 关键词: Characterization; Ultra; Molecular; Weight; Oilfield

In Canada, chemical flooding is currently being applied to increase recovery from a number of medium to heavy oil pools in southeast Alberta, southwest Saskatchewan and in the Lloydminster region. In cEOR operations, chemicals are injected into wells to increase oil recovery, but different reservoir operating conditions (e.g. pH, temperature, salinity and presence of alkali and/or surfactant) affect polymer structure and size. Changes in polymer structure or size ultimately compromise the incremental oil recovery performance, project economics, and also contribute to difficulties in its accurate detection and characterization in back produced water (and therefore its optimal reuse).***Therefore, various types of ultra-high molar mass polymers used in cEOR require an accurate description of polymer molar mass and hydrodynamic size for their optimal design. The present methods of oilfield polymer characterizations are limited to intrinsic viscosity measurement for molecular weight determination. The techniques, such as light scattering or microscopy, SEC, ultraviolet visible measurements and liquid chromatography, are not capable of accurately investigating these macromolecular complex structures for various reasons. Moreover, screening and selection procedure of polymers for cEOR are mainly relies on bulk rheological properties, while the role of extensional rheology is not well understood. Since polymer solutions can have markedly different shear and extensional behaviours, the limited knowledge of extensional data can lead to a highly misleading selection of chemicals for a given cEOR project.***To overcome these challenges, this work will be focused on following cutting edge research: 1) Injected polymer size and molecular structure characterization under different reservoir environment, 2) Developing method for detection and characterization of back produced cEOR polymers, 3) Measurements of cEOR chemical interaction for development of an optimal ASP slug, 4) Extensional rheological characterization and its role in cEOR performance, 5) Developing a credible database for modelling chemical flow through porous media. The effect of several parameters (e.g. pH, ionic strength, temperature and other reactant mixing ratios) on the molecular sizes, molar masses, molar mass distribution, and the formation of aggregates will be studied. Understanding these effects on polymer structure and size will enable the more efficient design of cEOR process. For the second phase of the research, the capillary breakup extensional rhometer will be used to examine the capillary breakup and elongation properties of various cEOR chemicals for different reservoir environments. The dynamics of the capillary thinning and breakup process for viscoelastic cEOR polymers together with polymer size and structure characterization will be used to find/design the best suitable chemical slug.**

在加拿大，目前正在应用化学洪水，以增加从艾伯塔省东南部，萨斯喀彻温省西南部和劳埃德明斯特地区的许多中型到重油池的恢复。在CEOR的操作中，化学物质被注入井中以增加石油回收率，但不同的储层工作条件（例如pH，温度，盐度和碱和/或表面活性剂的存在）会影响聚合物的结构和尺寸。聚合物结构或尺寸的变化最终会损害渐进的油回收率，项目经济学，并且在背部产生的水中的准确检测和表征上也很难（因此，其最佳的重复使用）。油田聚合物特征的当前方法仅限于确定分子量的固有粘度测量。由于各种原因，这些技术，例如光散射或显微镜，SEC，紫外线可见测量和液相色谱法，无法准确研究这些大分子复合物结构。此外，CEOR聚合物的筛选和选择程序主要依赖于批量流变特性，而扩展流变学的作用却尚不清楚。由于聚合物溶液可以明显不同，因此对特定CEOR项目的延伸数据知识有限会导致高度误导化学物质选择。 CEOR化学相互作用的测量用于开发最佳ASP SLUG，4）扩展流变学表征及其在CEOR性能中的作用，5）开发一个可靠的数据库，用于通过多孔培养基建模化学流。几个参数（例如pH，离子强度，温度和其他反应物混合比）对分子大小，摩尔质量，摩尔质量分布以及聚集体的形成的影响。了解这些对聚合物结构和大小的影响将使CEOR过程的更有效设计。对于研究的第二阶段，毛细管分解的延伸光度将用于检查各种CEOR化学物质在不同储层环境中的毛细血管破裂和伸长特性。粘弹性Ceor聚合物的毛细管变薄和分解过程以及聚合物大小和结构表征的动力学将用于查找/设计最佳合适的化学效果。**